SLCP Research Digest
(June & July 2014)
The SLCP Research Digest is a bi-monthly publication aimed at compiling the top research in fields related to short-lived
climate pollutants. While the Digest draws from a wide list of scientific research publications it is not meant to be a fully
exhaustive compilation of the relevant published research. Suggestions for published research to be included in future
Digests should be emailed to ccac_secretariat@unep.org, with the subject line 'For SLCP Research Digest' we particularly
welcome published research from non-English sources.
1
Note - To jump directly to a particular article or section, simply hold ctrl and left click on the title of the article or section
you wish to read.
Table of Contents
Methane ................................................................................................................................................................. 5
CH4 continuous measurements in the upper Spanish plateau ....................................................................................................... 5
Demonstration of an Ethane Spectrometer for Methane Source Identification ........................................................................ 5
Black Carbon ......................................................................................................................................................... 5
A review on black carbon emissions, worldwide and in China ..................................................................................................... 5
Relationship between black carbon and associated optical, physical and radiative properties of aerosols over two
contrasting environments..................................................................................................................................................................... 6
Atmospheric black carbon and warming effects influenced by the source and absorption enhancement in Central
Europe..................................................................................................................................................................................................... 6
Trend in Global Black Carbon Emissions from 1960 to 2007 ...................................................................................................... 7
Forty-seven years of weekly atmospheric black carbon measurements in the Finnish Arctic: Decrease in black
carbon with declining emissions ......................................................................................................................................................... 7
Cloud condensation nuclei (CCN) concentration in the Brazilian northeast semi-arid region: the influence of local
circulation ............................................................................................................................................................................................... 7
An Overview of the Studies on Black Carbon and Mineral Dust Deposition in Snow and Ice Cores in East Asia ............ 8
Climatology of aerosol optical properties and black carbon mass absorption cross section at a remote high-altitude
site in the western Mediterranean Basin ............................................................................................................................................ 8
Quantifying black carbon from biomass burning by means of levoglucosan – a one-year time series at the Arctic
observatory Zeppelin ............................................................................................................................................................................ 9
Historical trends of atmospheric black carbon on Sanjiang Plain as reconstructed from a 150-year peat record ................ 9
Effect of Solar Radiation on the Optical Properties and Molecular Composition of Laboratory Proxies of
Atmospheric Brown Carbon ............................................................................................................................................................. 10
Hydrofluorocarbons & Alternatives...................................................................................................................... 10
Experimental Assessment of residential split type air-conditioning systems using alternative refrigerants to R-22 at
high ambient temperatures ................................................................................................................................................................ 10
Theoretical comparison of low GWP alternatives for different refrigeration configurations taking R404A as baseline ... 11
Comparative Analysis of Various CO2 Configurations in Supermarket Refrigeration Systems ............................................ 11
Comparative thermodynamic analysis of a hybrid refrigeration system for promotion of cleaner technologies ................ 11
Visualization on Flow Patterns during Condensation of R410A in a Vertical Rectangular Channel .................................... 12
Investigation of Environmental and Heat Transfer Analysis of Air Conditioner Using Hydrocarbon Mixture
Compared to R-22............................................................................................................................................................................... 12
Performance Investigation of Some Hydro-Fluorocarbon Refrigerants with Low Global Warming as Substitutes to
R134a in Refrigeration Systems ........................................................................................................................................................ 12
Analysis of the Performance of the Evaporator of Automotive Air Conditioning System .................................................... 12
Exergy analysis of a domestic refrigerator using eco-friendly R290/R600a refrigerant mixture as an alternative to
R134a ..................................................................................................................................................................................................... 13
Tropospheric Ozone ............................................................................................................................................. 13
Ozone pollution: What can we see from space? A case study ..................................................................................................... 13
2
Threat to future global food security from climate change and ozone air pollution ............................................................... 14
Aerosol Air Pollution ............................................................................................................................................. 14
Personal and Indoor PM2.5 Exposure from Burning Solid Fuels in Vented and Unvented Stoves in a Rural Region
of China with a High Incidence of Lung Cancer ........................................................................................................................... 14
Variation in black carbon mass concentration over an urban site in the eastern coastal plains of the Indian subcontinent ............................................................................................................................................................................................... 15
Aerosols: The colour of smoke ......................................................................................................................................................... 15
Characterization of carbonaceous aerosols over Delhi in Ganga basin: seasonal variability and possible sources ............ 15
The effect of aerosol optical depth on rainfall with reference to meteorology over metro cities in India ........................... 15
Aerosol effects on cirrus through ice nucleation in the Community Atmosphere Model CAM5 with a statistical
cirrus scheme........................................................................................................................................................................................ 16
Decreased monsoon precipitation in the Northern Hemisphere due to anthropogenic aerosols ......................................... 16
Observational evidence of fire-driven reduction of cloud fraction in tropical Africa ............................................................. 17
Climate impacts of changing aerosol emissions since 1996 ......................................................................................................... 17
Remote sensing of aerosols in the Arctic for an evaluation of global climate model simulations ......................................... 17
Air Pollution & Health .......................................................................................................................................... 18
Short-term effects of air pollution on a range of cardiovascular events in England and Wales: case-crossover
analysis of the MINAP database, hospital admissions and mortality ......................................................................................... 18
PM2.5 Constituents and Hospital Emergency-Room Visits in Shanghai, China ..................................................................... 18
Burning in agricultural landscapes: an emerging natural and human issue in China ................................................................ 18
Ambient Air Pollution and Type 2 Diabetes Mellitus: A Systematic Review of Epidemiologic Research........................... 19
Particulate Matter Air Pollution Exposure, Distance to Road, and Incident Lung Cancer in the Nurses’ Health
Study Cohort ........................................................................................................................................................................................ 19
Agriculture ............................................................................................................................................................ 19
Invited Review: Enteric methane in dairy cattle production: Quantifying the opportunities and impact of reducing
emissions ............................................................................................................................................................................................... 20
Archaeal abundance in post-mortem ruminal digesta may help predict methane emissions from beef cattle ......................... 20
Simulation of biomass burning aerosols mass distributions and their direct and semi-direct effects over South
Africa using a regional climate model .............................................................................................................................................. 20
Sealing Rice Field Boundaries in Bangladesh: A Pilot Study Demonstrating Reductions in Water Use, Arsenic
Loading to Field Soils, and Methane Emissions from Irrigation Water..................................................................................... 21
Biomass Burning & Cooking and Heating .......................................................................................................... 21
Overuse of wood-based bioenergy in selected sub-Saharan Africa countries: review of unconstructive challenges
and suggestions .................................................................................................................................................................................... 21
Design and performance assessment of a rice husk fueled stove for household cooking in a typical sub-Saharan
setting .................................................................................................................................................................................................... 22
Effect of gradients in biomass burning aerosol on shallow cumulus convective circulations ................................................ 22
Soot superaggregates from flaming wildfires and their direct radiative forcing ........................................................................ 22
Brownness of organics in aerosols from biomass burning linked to their black carbon content .......................................... 22
Effects of biomass burning on climate, accounting for heat and moisture fluxes, black and brown carbon, and
cloud absorption effects ..................................................................................................................................................................... 23
Waste ..................................................................................................................................................................... 23
3
Global Emissions of Trace Gases, Particulate Matter, and Hazardous Air Pollutants from Open Burning of
Domestic Waste................................................................................................................................................................................... 23
Transport & Industry ............................................................................................................................................ 24
Analysis of greenhouse gas emissions of freight transport sector in China............................................................................... 24
Fossil Fuels ........................................................................................................................................................... 24
Global Bottom-Up Fossil Fuel Fugitive Methane and Ethane Emissions Inventory for Atmospheric Modeling ............. 24
Assessment and risk analysis of casing and cement impairment in oil and gas wells in Pennsylvania, 2000–2012 ............ 24
Natural Gas Fugitive Emissions Rates Constrained by Global Atmospheric Methane and Ethane..................................... 25
Methane Destruction Efficiency of Natural Gas Flares Associated with Shale Formation Wells ......................................... 25
Cross Cutting & Emerging SLCP Source Sectors ................................................................................................ 25
Pediatric burns in military hospitals of China from 2001 to 2007: A retrospective study ...................................................... 25
Global Methane Emissions from Pit Latrines ................................................................................................................................ 26
4
Click Here to Return to the Table of Contents
METHANE
CH4 continuous measurements in the upper Spanish plateau
Abstract: Continuous methane, CH4, concentrations were measured in a rural area of the upper Spanish plateau from June
2010 to May 2012 by cavity ringdown spectroscopy technique. The results obtained have proven the local impact of
anthropogenic nearby sources on CH4 concentrations, and evidence a significant influence on the overall mean, averaged
daily and seasonal patterns recorded at the measuring site. The positive anomalies in CH 4 concentrations, statistically
significant at 95 %, in the southeast sector, defined here as ESE, SE, SSE and S sectors, have been attributed to the
contribution of the Valladolid urban plume and the urban landfill. Based on this finding, CH 4 background levels were
associated to the concentrations recorded in the remaining un-disturbed sectors. CH4 means of the overall data set, the
southeast sector and background sectors yielded average means of 1,894.1, 1,927.9 and 1,887.1 ppb, respectively. The diurnal
and seasonal patterns of the overall data set and background concentrations have shown that CH4 concentrations are mainly
dominated by its reaction with OH radicals. Maximum hourly concentrations were reached during night-time and early
morning, 5–7 h, whereas minimum concentrations were recorded at 16 h. Maximum and minimum monthly means were
recorded in January and July, respectively. The diurnal and seasonal amplitudes, namely, peak-to-peak means, of background
concentrations were 25.1 and 48.1 ppb, respectively. These values were significantly lower than those obtained for the overall
data set, 42.9 and 58.1 ppb, revealing the significant role of local influences on CH4 concentrations despite the low frequency
of southeast winds recorded at the measuring site, 16.9 %.
Sánchez M. L., M. Á. García, I. A. Pérez, & N. Pardo (2014) CH4 continuous measurements in the upper Spanish plateau, ENVIRON.
MONIT. ASSES. 186:2823-2834.
Demonstration of an Ethane Spectrometer for Methane Source Identification
Abstract - Methane is an important greenhouse gas and tropospheric ozone precursor. Simultaneous observation of ethane
with methane can help identify specific methane source types. Aerodyne Ethane-Mini spectrometers, employing recently
available mid-infrared distributed feedback tunable diode lasers (DFB-TDL), provide 1 s ethane measurements with sub-ppb
precision. In this work, an Ethane-Mini spectrometer has been integrated into two mobile sampling platforms, a ground
vehicle and a small airplane, and used to measure ethane/methane enhancement ratios downwind of methane sources.
Methane emissions with precisely known sources are shown to have ethane/methane enhancement ratios that differ greatly
depending on the source type. Large differences between biogenic and thermogenic sources are observed. Variation within
thermogenic sources are detected and tabulated. Methane emitters are classified by their expected ethane content. Categories
include the following: biogenic (<0.2%), dry gas (1−6%), wet gas (>6%), pipeline grade natural gas (<15%), and processed
natural gas liquids (>30%). Regional scale observations in the Dallas/Fort Worth area of Texas show two distinct
ethane/methane enhancement ratios bridged by a transitional region. These results demonstrate the usefulness of continuous
and fast ethane measurements in experimental studies of methane emissions, particularly in the oil and natural gas sector.
Yacovitch, T. I., S. C. Herndon, J. R. Roscioli, C. Floerchinger, R. M. McGovern, M. Agnese, G. Petron, ́J. Kofler, C.
Sweeney, A. Karion, S. A. Conley, E. A. Kort, L. Nahle, M. Fischer, L. Hildebrandt, J. Koeth, J. B. McManus, D. D. Nelson,
M. S. Zahniser, & C. E. Kolb (2014) Demonstration of an Ethane Spectrometer for Methane Source Identification, ENVIRONMENTAL
SCIENCE & TECHNOLOGY.
Click Here to Return to the Table of Contents
BLACK CARBON
A review on black carbon emissions, worldwide and in China
Abstract - Black carbon (BC) produced from open burning (OB) and controlled combustion (CC) is a range of
carbonaceous products of incomplete combustion of biomass and fossil fuel, and is deemed as one of the major contributors
to impact global environment and human health. BC has a strong relationship with POPs, in waste combustion, BC
promotes the formation of POPs, and then the transport of POPs in the environment is highly influenced by BC. However
5
less is known about BC formation, measurement and emissions estimation especially in developing countries such as China.
Different forms of BC are produced both in CC and OB. BC emission characteristics and combustion parameters which
determine BC emissions from CC and OB are discussed. Recent studies showed a lack of common methodology and the
resulting data for describing the mechanisms related to BC formation during combustion processes. Because BC is a
continuum carbonaceous combustion product, different sampling and measuring methods are used for measuring their
emissions with great quantitative uncertainty. We discuss the commonly used BC sampling and measuring methods along
with the causes for uncertainty and measures to minimizing the uncertainty. Then, we discuss the estimations of BC emission
factors and emission inventory for CC and OB sources. The total emissions of BC from CC and OB in China are also
estimated and compared with previous BC emission inventories in this review and we find the inventories tend to be
overestimated. As China becomes the largest contributor to global BC emissions, studies for characterizing BC emissions
from OB and CC sources are absent in China. Finally, we comment on the current state of BC emission research and
identify major deficiencies that need to overcome. Moreover, the advancement in research tools, measuring technique in
particular, as discussed in this review is critical for researchers in developing countries to improve their capability to study
BC emissions for addressing the growing climate change and public health concerns.
Ni, M., J. Huang, S. Lu, X. Li, J. Yan, & K. Cen (2014) A review on black carbon emissions, worldwide and in China, CHEMOSPHERE
107:83-93.
Relationship between black carbon and associated optical, physical and radiative properties of aerosols
over two contrasting environments
Abstract - The first simultaneous aethalometer and solar radiometer measurements of black carbon (BC) mass
concentration (surface-level) and aerosol optical, microphysical and radiative parameters (columnar) have been made during
2005–2011 over two contrasting experimental sites, one representing background rural environment (Sinhagad) and the
other surrounded by urban environment (Pune) in the south-west India. The long-term diurnal cycle of BC aerosols over
both sites exhibited a strong peak during daytime and a weaker plateau around evening–midnight hours, implying the
influence of anthropogenic emissions as well as changes in planetary boundary layer (PBL). The multi-year seasonal mean
variation in BC concentration shows the highest during winter and lowest during monsoon seasons, which is found to be
inversely related to the variations in single scattering albedo (SSA). Moreover, the BC variations were found to be strongly
associated with greater values of Angstrom exponent (α), indicating that the observed BC involves abundance of fine-mode
aerosol fraction. The higher concentrations of BC during winter and lower concentrations during pre-monsoon over both
Pune and Sinhagad are noticed to be closely linked with aerosol optical depth, revealing significant contribution of BC to the
composite aerosol over both the regions. The columnar AOD and Angstrom exponent also showed relatively greater optical
depth and α values during winter as compared to pre-monsoon season over both sites.
Safai, P.D., P.C.S. Devara, M.P. Raju, K. Vijayakumar, P.S.P. Rao (2014) Relationship between black carbon and associated optical,
physical and radiative properties of aerosols over two contrasting environments, ATMOSPHERIC RESEARCH 149:292-299.
Atmospheric black carbon and warming effects influenced by the source and absorption enhancement in
Central Europe
Abstract - Particles containing black carbon (BC), a strong absorbing substance, exert a rather uncertain direct and indirect
radiative forcing in the atmosphere. To investigate the mass concentration and absorption properties of BC particles over
Central Europe, the model WRF-Chem was used at a resolution of 12 km in conjunction with a high resolution BC emission
inventory (EUCAARI 42-Pan-European Carbonaceous Aerosol Inventory; 1/8° × 1/16°). The model simulation was
evaluated using measurements of equivalent soot carbon, absorption coefficients and particle number concentrations at 7
sites within the German Ultrafine Aerosol Network, PM10 mass concentrations from the dense measurement network of the
German Federal Environmental Agency at 392 monitoring stations, and aerosol optical depth from MODIS and
AERONET. A distinct time period (25 March to 10 April 2009) was chosen, during which the clean marine air mass
prevailed in the first week and afterwards the polluted continental air mass mainly from south-east dominated with elevated
daily average BC concentration up to 4 μg m−3. The simulated PM10 mass concentration, aerosol number concentration and
optical depth were in a good agreement with the observations, while the modelled BC mass concentrations were found to be
a factor of 2 lower than the observations. Together with backtrajectories, detailed model bias analyses suggested that the
current BC emission in countries to the east and south of Germany might be underestimated by a factor of 5, at least for the
simulation period. Running the model with upscaled BC emissions in these regions led to a smaller model bias and a better
correlation between model and measurement. On the contrary, the particle absorption coefficient was positively biased by
6
about 20% even when the BC mass concentration was underestimated by around 50%. This indicates that the internal
mixture treatment of BC in the WRF-Chem optical calculation is unrealistic in our case, which over amplifies the light
absorption by BC containing particles. By adjusting the modeled mass absorption cross-section towards the measured values,
the simulation of particle light absorption of BC was improved as well. Finally, the positive direct radiative forcing of BC
particles at top of the atmosphere was estimated to be in the range of 0 to +4 W m−2 over Germany for the model run with
improved BC mass concentration and adjusted BC light absorption cross-section. This treatment lowered the positive
forcing of BC by up to 70%, compared with the internal mixing treatment of BC in the model simulation.
Nordmann, S., Y. F. Cheng, G. R. Carmichael, M. Yu, H. A. C. Denier van der Gon, Q. Zhang, P. E. Saide, U. Pöschl, H.
Su, W. Birmili, & A. Wiedensohler1 (2014) Atmospheric black carbon and warming effects influenced by the source and absorption
enhancement in Central Europe, ATMOS. CHEM. PHYS. DISCUSS. 14:14637-14682.
Trend in Global Black Carbon Emissions from 1960 to 2007
Abstract - Black carbon (BC) plays an important role in both climate change and health impact. Still, BC emissions as well as
the historical trends are associated with high uncertainties in existing inventories. In the present study, global BC emissions
from 1960 to 2007 were estimated for 64 sources, by using recompiled fuel consumption and emission factor data sets.
Annual BC emissions had increased from 5.3 (3.4−8.5 as an interquartile range) to 9.1 (5.6−14.4) teragrams during this
period. Our estimations are 11−16% higher than those in previous inventories. Over the period, we found that the BC
emission intensity, defined as the amount of BC emitted per unit of energy production, had decreased for all the regions,
especially China and India. Improvements in combustion technology and changes in fuel composition had led to an increase
in energy use efficiency, and subsequently a decline of BC emission intensities in power plants, the residential sector, and
transportation. On the other hand, the BC emission intensities had increased in the industrial and agricultural sectors, mainly
due to an expansion of low-efficiency industry (coke and brick production) in developing countries and to an increasing
usage of diesel in agriculture in developed countries.
Wang, R., S. Tao, H. Shen, Y. Huang, H. Chen, Y. Balkanski, O. Boucher, P. Ciais, G. Shen, W. Li, Y. Zhang, Y. Chen, N.
Lin, S. Su, B. Li, J. Liu, & W. Liu (2014) Trend in Global Black Carbon Emissions from 1960 to 2007, ENVIRON. SCI. TECHNOL.
LETT. 48(12)6780-6787.
Forty-seven years of weekly atmospheric black carbon measurements in the Finnish Arctic: Decrease in black
carbon with declining emissions
Abstract - Concentrations of atmospheric black carbon, [BC], were determined from filter samples collected weekly at Kevo,
Finland (69°45′N, 27°02′E), from 1964 to 2010 using optical and thermal optical methods. The data provide the longest
record of directly measured [BC] in the Arctic. The mean winter, spring, summer, and autumn [BC] based on the entire data
set were 339, 199, 127, and 213 ng m−3, respectively. Annual mean [BC] decreased from ~300 in ~1970 to 82 ng m−3 in 2010.
[BC] data sets from other Arctic sites show similar trends, but concentrations at Kevo are generally higher. From ~1970 to
2010 the [BC] decreased by ~1.8% yr−1. However, [BC] did not decrease monotonically. Instead, cyclical peaks occurred
around 1976–1977, 1985–1987, and 1999. During such periods, nickel concentrations were well correlated with [BC]. This
suggests that emissions from extensive ore smelting on the Kola Peninsula were significant contributors of particulate matter
observed at Kevo. Simulations of [BC] at Kevo using the OsloCTM3 model using different emission inventories and
meteorological data sets were performed. Modeled concentrations were lower than observed by a factor of 4. The results
indicated that circulation changes can explain year to year variability, but the downward trend in the observations is mostly
explained by emissions. Emission inventories in Europe, Russia, and the former Soviet Union are poorly constrained and
appear to need revision in order to match observed trends in BC atmospheric concentrations.
Dutkiewicz, V. A., Anthony M. DeJulio, Tanveer Ahmed, James Laing, Philip K. Hopke, Ragnhild B. Skeie, Yrjö Viisanen,
Jussi Paatero, & Liaquat Husain (2014) Forty-seven years of weekly atmospheric black carbon measurements in the Finnish Arctic: Decrease
in black carbon with declining emissions, JOURNAL OF GEOPHYSICAL RESEARCH: ATMOSPHERES (Early View).
Cloud condensation nuclei (CCN) concentration in the Brazilian northeast semi-arid region: the influence
of local circulation
Abstract - Ground-based aerosol instrumentation covering particle size diameters from 25 nm to 32 lm was deployed to
determine aerosol concentration and cloud condensation nuclei (CCN)-activation properties at water vapor supersaturations
in the range of S = 0.20–1.50 % in the remote Brazilian northeast semi-arid region (NEB) in coastal (maritime) and
7
continental (inland) regimes. The instruments measured aerosol number concentration and activation spectra for CCN and
revealed that aerosol properties are sensitive with respect to the sources as a function of the local wind circulation system.
The observations show that coastal aerosol total number concentrations are above 3,000 cm -3 on average, exhibiting
concentration peaks depending on the time of the day in a consistent daily pattern. The variation on aerosol concentration
has also influences on the fraction of particles active as CCN. At 1.0 % water vapor supersaturation, the fraction can reach as
high as 80 %. Inland aerosol total concentrations were about 1,800–1,900 cm-3 and did not show much diurnal variation. The
fraction of particles active as CCN observed inland depend on the history of the air masses, and was much higher when air
masses were originated over the sea. It was found that (NH4)2SO4 and NaCl are the major soluble inorganic fraction of the
aerosols at the coast. The major fraction of NaCl was present in the coarse mode, while ammonium sulfate dominates the
inorganic fraction at the submicron range, with about 10 % of the total aerosol mass at 0.32 lm. Inorganic compounds are
almost absent in particles with sizes around 0.1 lm. The study suggests that the air masses with high concentration of CCN
originate at the sea. The feasible explanation lies in the fact that the NEB’s beaches have a particular morphology that
produces a wide surf zone and creates a large load of aerosols when combined with strong and permanent winds of the
region.
Almeida, G. P., S. Borrmann, J. B. V. Leal Jr. (2014) Cloud condensation nuclei (CCN) concentration in the Brazilian northeast semi-arid
region: the influence of local circulation, METEOROL. ATMOS. PHYS. 125:159-176.
An Overview of the Studies on Black Carbon and Mineral Dust Deposition in Snow and Ice Cores in East
Asia
Abstract - Black carbon (BC) is the most effective insoluble light-absorbing particulate (ILAP), which can strongly absorb
solar radiation at visible wavelengths. Once BC is deposited in snow via dry or wet process, even a small amount of BC
could significantly decrease snow albedo, enhance absorption of solar radiation, accelerate snow melting, and cause climate
feedback. BC is considered the second most important component next to CO2 in terms of global warming. Similarly,
mineral dust (MD) is another type of ILAP. So far, little attention has been paid to quantitative measurements of BC and
MD deposition on snow surface in the midlatitudes of East Asia, especially over northern China. In this paper, we focus on
reviewing several experiments performed for collecting and measuring scavenging BC and MD in the high Asian glaciers
over the mountain range (such as the Himalayas) and in seasonal snow over northern China. Results from the surveyed
literature indicate that the absorption of ILAP in seasonal snow is dominated by MD in the Qilian Mountains and by local
soil dust in the Inner Mongolian region close to dust sources. The detection of BC in snow and ice cores using modern
techniques has a large bias and uncertainty when the snow sample is mixed with MD. Evidence also indicates that the
reduction of snow albedo by BC and MD perturbations can significantly increase the net surface solar radiation, cause
surface air temperature to rise, reduce snow accumulation, and accelerate snow melting.
Xin, W., X. Baiqing, & M. Jing (2014) An Overview of the Studies on Black Carbon and Mineral Dust Deposition in Snow and Ice Cores
in East Asia, J. OF METEOROLOGICAL RES. 28(3):354-370.
Climatology of aerosol optical properties and black carbon mass absorption cross section at a remote
high-altitude site in the western Mediterranean Basin
Abstract - Aerosol light scattering (_sp), backscattering (_bsp) and absorption (_ap) were measured at Montsec (MSC;
42_30 N, 0_440 E, 1570ma.s.l.), a remote highaltitude site in the western Mediterranean Basin. Mean (±SD) _sp, _bsp and
_ap were 18.9±20.8, 2.6±2.8 and 1.5±1.4Mm−1, respectively at 635 nm during the period under study (June 2011–June
2013). Mean values of singlescattering albedo (SSA, 635 nm), the scattering Ångström exponent (SAE, 450–635 nm),
backscatter-to-scatter ratio (B /S, 635 nm), asymmetry parameter (g, 635 nm), black carbon mass absorption cross section
(MAC, 637 nm) and PM2.5 mass scattering cross section (MSCS, 635 nm) were 0.92±0.03, 1.56±0.88, 0.16±0.09, 0.53±0.16,
10.9±3.5m2 g−1 and 2.5±1.3m2 g−1, respectively. The scattering measurements performed at MSC were in the
medium/upper range of values reported by Andrews et al. (2011) for other mountaintop sites in Europe due to the frequent
regional recirculation scenarios (SREG) and Saharan dust episodes (NAF) occurring mostly in spring/summer and causing
the presence of polluted layers at the MSC altitude. However, the development of upslope winds and the possible presence
of planetary boundary layer air at MSC altitude in summer may also have contributed to the high scattering observed. Under
these summer conditions no clear diurnal cycles were observed for the measured extensive aerosol optical properties (_sp,
_bsp and _ap). Conversely, low _sp and _ap at MSC were measured during Atlantic advections (AA) and winter regional
anticyclonic episodes (WREG) typically observed during the cold season in the western Mediterranean. Therefore, a seasondependent decrease in the magnitude of aerosol extensive properties was observed when MSC was in the free troposphere,
8
with the highest free-troposphere vs. all-data difference observed in winter and the lowest in spring/summer. The location
of MSC station allowed for a reliable characterization of aerosols as a function of the main synoptic meteorological patterns.
The SAE was the lowest during NAF and showed an inverse correlation with the outbreak intensity, indicating a progressive
shift toward larger particles. Moreover, the strength of NAF episodes in the region led to a slope of the scattering vs.
absorption relationship among the lowest reported for other mountaintop sites worldwide, indicating that MSC was
dominated by dust aerosols at high aerosol loading. As a consequence, SSA showed a nearly monotonic increase with
increasing particle concentration and scattering. The SAE was the highest during SREG, indicating the presence of polluted
layers dominated by smaller particles. Correspondingly, the asymmetry parameter was lower under SREG compared with
NAF. The MAC and MSCS were significantly higher during NAF and SREG compared to AA and WREG, indicating an
increase of absorption and scattering efficiencies associated with the summer polluted scenarios. The optical measurements
performed at the MSC remote site were compared with those simultaneously performed at a regional background station in
the western Mediterranean Basin located at around 700ma.s.l. upstream of the MSC station.
Pandolfi, M., A. Ripoll, X. Querol, & A. Alastuey (2014) Climatology of aerosol optical properties and black carbon mass absorption cross
section at a remote high-altitude site in the western Mediterranean Basin, ATMOS. CHEM. PHYS. 14:6443–6460.
Quantifying black carbon from biomass burning by means of levoglucosan – a one-year time series at the
Arctic observatory Zeppelin
Abstract - matter from biomass burning, has been used to study the influence of residential wood burning, agricultural waste
burning and Boreal forest fire emissions on the Arctic atmosphere black carbon (BC) concentration. A one-year time series
from March 2008 to March 2009 of levoglucosan has been established at the Zeppelin observatory in the European Arctic.
Elevated concentrations of levoglucosan in winter (mean: 1.02 ngm−3) compared to summer (mean: 0.13 ngm−3) were
observed, resembling the seasonal variation seen for e.g. sulfate and BC. The mean concentration in the winter period was 2–
3 orders of magnitude lower than typical values reported for European urban areas in winter, and 1–2 orders of magnitude
lower than European rural background concentrations. Episodes of elevated levoglucosan concentration lasting from 1 to 6
days were more frequent in winter than in summer and peak values were higher, exceeding 10 ngm−3 at the most.
Concentrations of elemental carbon from biomass burning (ECbb) were obtained by combining measured concentrations of
levoglucosan and emission ratios of levoglucosan and EC for wildfires/agricultural fires and for residential wood burning.
Neglecting chemical degradation by OH provides minimum levoglucosan concentrations, corresponding to a mean ECbb
concentration of 3.7±1.2 ngm−3 in winter (October–April) and 0.8±0.3 ngm−3 in summer (May– September), or 8.8±4.5%
of the measured equivalent black carbon (EBC) concentration in winter and 6.1±3.4% in summer. When accounting for
chemical degradation of levoglucosan by OH, an upper estimate of 31–45% of EBC could be attributed to EC_bb (ECbb
adjusted for chemical degradation) in winter, whereas no reliable (<100 %) upper estimate could be provided for summer for
the degradation rates applied. Hence, fossil fuel sources appear to dominate the European Arctic BC concentrations in
winter, whereas the very wide range obtained for summer does not allow us to conclude upon this for the warm season.
Calculations using the Lagrangian particle dispersion model FLEXPART show that the seasonal variation of the modeled
ECbb (ECbb,m) concentration compared relatively well with observationally derived ECbb from agricultural fires/wildfires
during summer, and residential wood burning in winter. The model overestimates by a factor of 2.2 in winter and 4.4 in
summer when compared to the observationally derived mean ECbb concentration, which provides the minimum estimate,
whereas it underestimates by a factor of 2.3–3.3 in winter and a factor of 4.5 in summer when compared to EC_bb, which
provides the upper estimate. There are indications of too-low emissions of residential wood burning in northern Russia, a
region of great importance with respect to observed concentrations of BC in the European Arctic.
Yttri K. E., C. L. Myhre, S. Eckhardt, M. Fiebig, C. Dye, D. Hirdman, J. Ström, Z. Klimont, & A. Stohl (2014) Quantifying
black carbon from biomass burning by means of levoglucosan – a one-year time series at the Arctic observatory Zeppelin, ATMOS. CHEM.
PHYS., 14, 6427–6442.
Historical trends of atmospheric black carbon on Sanjiang Plain as reconstructed from a 150-year peat
record
Abstract - Black carbon (BC), one of the major components of atmosphere aerosol, could be the second dominant driver of
climate change. We reconstructed historical trend of BC fluxes in Sanjiang Plain (Northeast China) through peat record to
better understand its long-term trend and relationship of this atmosphere aerosol with intensity of human activities. The BC
fluxes in peatland were higher than other sedimentary archives. Although global biomass burning decreased in last 150 years,
9
regional large scale reclaiming caused BC fluxes of the Sanjiang Plain increased dramatically between 1950s' and 1980s', most
likely resulting from using fire to clearing dense pastures and forests for reclaiming. The BC fluxes have increased since
1900s with increasing of the population and the area of farmland; the increase trend has been more clearly since 1980s.
Based on Generalized additive models (GAM), the proportional influence of regional anthropogenic impacts have increased
and became dominant factors on BC deposition.
Gao, C., Q. Lin, S. Zhang, J. He, X. Lu, & G. Wang (2014) Historical trends of atmospheric black carbon on Sanjiang Plain as
reconstructed from a 150-year peat record, SCIENTIFIC REPORTS 4(5723).
Effect of Solar Radiation on the Optical Properties and Molecular Composition of Laboratory Proxies of
Atmospheric Brown Carbon
Abstract - Sources, optical properties, and chemical composition of atmospheric brown carbon (BrC) aerosol are uncertain,
making it challenging to estimate its contribution to radiative forcing. Furthermore, optical properties of BrC may change
significantly during its atmospheric aging. We examined the effect of photolysis on the molecular composition, mass
absorption coefficient, and fluorescence of secondary organic aerosol (SOA) prepared by high-NOx photooxidation of
naphthalene (NAP SOA). Our experiments were designed to model photolysis processes of NAP SOA compounds
dissolved in cloud or fog droplets. Aqueous solutions of NAP SOA were observed to photobleach (i.e., lose their ability to
absorb visible radiation) with an effective halflife of ∼15 h (with sun in its zenith) for the loss of near-UV (300-400 nm)
absorbance. The molecular composition of NAP SOA was significantly modified by photolysis, with the average SOA
formula changing from C14.1H14.5O5.1N0.085 to C11.8H14.9O4.5N0.023 after 4 h of irradiation. However, the average
O/C ratio did not change significantly, suggesting that it is not a good metric for assessing the extent of photolysis-driven
aging in NAP SOA (and in BrC in general). In contrast to NAP SOA, the photobleaching of BrC material produced by the
reaction of limonene + ozone SOA with ammonia vapor (aged LIM/O3 SOA) was much faster, but it did not result in a
significant change in molecular composition. The characteristic absorbance of the aged LIM/O3 SOA in the 450-600 nm
range decayed with an effective half-life of < 0.5 h. This result emphasizes the highly variable and dynamic nature of
different types of atmospheric BrC.
Lee, H. J., P. Aiona, A. Laskin, J. Laskin, & S. A. Nizkorodov (2014) Effect of Solar Radiation on the Optical Properties and
Molecular Composition of Laboratory Proxies of Atmospheric Brown Carbon, ENVIRON. SCI. TECHNOL. (Accepted Manuscript).
Click Here to Return to the Table of Contents
HYDROFLUOROCARBONS & ALTERNATIVES
Experimental Assessment of residential split type air-conditioning systems using alternative refrigerants to
R-22 at high ambient temperatures
Abstract - Steady state performance of residential air conditioning systems using R22 and alternatives R290, R407C, R410A,
at high ambient temperatures, have been investigated experimentally. System performance parameters such as optimum
refrigerant charge, coefficient of performance, cooling capacity, power consumption, pressure ratio, power per ton of
refrigeration and TEWI environmental factor have been determined. All refrigerants were tested in the cooling mode
operation under high ambient air temperatures, up to 55 _C, to determine their suitability. Two split type air conditioner of 1
and 2 TR capacities were used. A psychrometric test facility was constructed consisting of a conditioned cool compartment
and an environmental duct serving the condenser. Air inside the conditioned compartment was maintained at 25 _C dry bulb
and 19 _C wet bulb for all tests. In the environmental duct, the ambient air temperature was varied from 35 _C to 55 _C in 5
_C increments. The study showed that R290 is the better candidate to replace R22 under high ambient air temperatures. It
has lower TEWI values and a better coefficient of performance than the other refrigerants tested. It is suitable as a drop-in
refrigerant. R407C has the closest performance to R22, followed by R410A.
Joudi, K. A., Q. R. Al-Amir (2014) Experimental Assessment of residential split type air-conditioning systems using
alternative refrigerants to R-22 at high ambient temperatures, Energy Conversion & Management 86:496-506.
10
Theoretical comparison of low GWP alternatives for different refrigeration configurations taking R404A as
baseline
Abstract - Six refrigerants are evaluated as low GWP replacements for R404A using different configurations, including twostage system architectures. These refrigerants are selected according to similar characteristics to R404A, and they are the midterm alternatives R407A and R407F, and the long-term alternatives: L40 and DR-7 (with very low GWP and low
flammability), N40 and DR-33 (with low GWP and no flammability). In order to have a complete comparison range, various
operating conditions are considered, covering low and medium evaporator temperatures and two levels of condensation
temperatures. Configurations selected are presented and the equations used to simulate the expected performance are shown.
From a given cooling capacity, volumetric flow rate and COP are compared, taking R404A as baseline. The most efficient
alternatives are the low-flammable refrigerants, L40 and DR-7, and when no flammability is acceptable, N40 and DR-33 are
also very good options.
Mota-Babiloni, A., J. Navarro-Esbrı´, A. Barraga´n, F. Mole´s, B. Peris (2014) Theoretical comparison of low GWP alternatives for
different refrigeration configurations taking R404A as baseline, INTERNATIONAL JOURNAL OF REFRIGERATION 44:81-90.
Comparative Analysis of Various CO2 Configurations in Supermarket Refrigeration Systems
Abstract - This paper presents an analysis of various CO2 transcritical and cascade/secondary loop refrigeration systems
that are becoming popular in supermarket applications with the objective of optimizing the operating parameters of these
systems. In addition, the performance of selected CO2-based refrigeration systems is compared to the baseline R404A
multiplex direct expansion system using bin analyses in the eight climate zones of the United States. For the refrigeration
systems investigated, it was found that the Transcritical Booster System with Bypass Compressor (TBS-BC) had the lowest
energy consumption for ambient temperatures (Tamb) less than 8°C, and for higher ambient temperatures the R404A direct
expansion system was found to have the lowest energy consumption. Also, the TBS-BC performs equivalent to or better
than the R404A direct expansion system in the northern two-thirds of the US. For the southern portion of the US, the
R404A multiplex DX system performs better than CO2 systems
Sharma, V., B. Fricke, P. Bansal (2014) Comparative Analysis of Various CO2 Configurations in Supermarket Refrigeration Systems,
INTERNATIONAL JOURNAL OF REFRIGERATION (accepted manuscript).
Comparative thermodynamic analysis of a hybrid refrigeration system for promotion of cleaner
technologies
Abstract - This article presents a comparative thermodynamic analysis based on numerical methods for a hybrid
refrigeration system suitable to operate as vapour absorption system (VA), vapour compression–absorption system (VCA)
and vapour compression system (VC). The working fluid employed for the first two systems is ammonia–water and it is pure
ammonia in case of the third system. The system is being powered by waste energy and conventional energy depending on
the mode of operation. The effect on performance parameters like COP and exergy efficiency during all modes of operation
has been evaluated by keeping the uniform parametric conditions like condenser temperature (40ºC) and evaporator
temperature (5ºC) for all the modes of operation. The effect of ambient temperature on the exergy loss in each component
of the different modes of operation have also been evaluated and discussed. The results obtained indicate that COP and
exergy efficiency for VCA mode initially increases and then decreases whereas for VA and VC mode the COP and exergy
efficiency decreases with condenser temperature. The analysis also reveals that with the variation in evaporator temperature
the COP and exergy efficiency for VC mode increases whilst for VA and VCA mode the COP shows a slight increase
whereas exergy efficiency decreases. The variation of exergy efficiency and exergy loss in different components with
condenser and evaporator temperature shows that exergy efficiency is found to be the highest in VC mode whereas the
lowest in VCA mode for both the temperature variations. The variation of compressor work and exergy loss in compressors
with evaporator and condenser temperature shows that compressor work and exergy loss is lesser for VCA mode when
compared to VC mode.
Anand, S., A. Gupta, & S. K. Tyagi (2014) Comparative thermodynamic analysis of a hybrid refrigeration system for promotion of cleaner
technologies, J. THERM. ANAL. CALORIM.
11
Visualization on Flow Patterns during Condensation of R410A in a Vertical Rectangular Channel
Abstract - The visualization experiments on HFC R410A condensation in a vertical rectangular channel (14.34mm hydraulic
diameter, 160mm length) were investigated. The flow patterns and heat transfer coefficients of condensation in the inlet
region were presented in this paper. Better heat transfer performance can be obtained in the inlet region, and flow regime
transition in other regions of the channel was also observed. Condensation experiments were carried out at different mass
fluxes ( from 1.6 kg/h to 5.2 kg/h) and at saturation temperature 28ºC. It was found that the flow patterns were mainly
dominated by gravity at low mass fluxes. The effects of interfacial shear stress on condensate fluctuation are significant for
the film condensation at higher mass flux in vertical flow, and consequently, the condensation heat transfer coefficient
increases with the mass flux in the experimental conditions. The drop formation and growth process of condensation were
also observed at considerably low refrigerant vapor flow rate.
Wenyun X., & J. Li (2014) Comparative thermodynamic analysis of a hybrid refrigeration system for promotion of cleaner technologies, J. OF
THERMAL SCIENCE 23(3):269-274.
Investigation of Environmental and Heat Transfer Analysis of Air Conditioner Using Hydrocarbon
Mixture Compared to R-22
Abstract - Hydrocarbons are natural fluids which create less environmental effect in nature and cause less emission also.
This paper emphasizes the heat-transfer performances and global warming potential of the existing refrigerant, R-22, and
compares it with some hydrocarbon mixtures for the domestic air conditioner. Propane with different proportions is taken
for comparison. R-134a and R-407C are also used as refrigerants in the refrigerators and in commercial or large scale air
conditioners, respectively. Two mixtures of R-290 with R-22 having proportions 25:75 and 50:50 by mass are used for
comparison. Global warming potential of R-22 is flammable refrigerant. Mixing of R-290 with R-22 reduces the
globalwarming potential, and also reduces the flammability issue. This mixture finds better heat transfer enhancement
compared to that of R-22. Thus, the heat transfer coefficient for the mixture increases up to 20–30 % compared to that of
R-22. Indirectly it causes to reduce the requirement of refrigerant charges, and hence, the emission in the environment will
also be reduced.
Ahamed, J. U., R. Saidur, & H. H. Masjuki (2014) Investigation of Environmental and Heat Transfer Analysis of Air Conditioner Using
Hydrocarbon Mixture Compared to R-22, ARAB. J. SCI. ENG. 39:4141-4150.
Performance Investigation of Some Hydro-Fluorocarbon Refrigerants with Low Global Warming as
Substitutes to R134a in Refrigeration Systems
Abstract - In this study, the performances of R152a, R161, and R1234yf with very low global warming potential were
investigated theoretically as alternatives to R134a in vapor compression refrigeration systems. The results obtained showed
that the saturation vapor pressures for R152a and R1234yf are very close to that of R134a, which indicates similar properties,
while that of R161, between the temperature range of −30 to 40◦C, deviated significantly by 49.2%. R152a emerged as the
most energy efficient of the investigated refrigerants with average power per ton of refrigeration (PPTR) of 30.5% less than
that of R134a. R152a and R161 exhibited a higher volumetric refrigerating capacity (VRC) and coefficient of performance
(COP) than R134a. The highest COP was obtained using R152a in the system with an average value of 43.5% higher than
that of R134a, while the average COPs for R161 and R1234yf are 4.8% higher and 7.1% lower, respectively. Generally,
R152a performed better than the other two alternatives as R134a substitute in that it has similar saturation pressure as R134a,
exhibited lowest PPTR, very high VRC, and highest COP. Major system redesign will be required before R161 can be
employed as R134a substitute. Also, low performance of R1234yf in terms of PPTR, VRC and COP will increase its indirect
contributions to global warming.
Bolaji, B.O. & Z. Huan (2014) Performance Investigation of Some Hydro-Fluorocarbon Refrigerants with Low Global Warming as
Substitutes to R134a in Refrigeration Systems, J. OF ENGINEERING THERMOPHYSICS 23(2).
Analysis of the Performance of the Evaporator of Automotive Air Conditioning System
Abstract - The purpose of this research was to establish a theoretical model for the evaporator of automotive air
conditioning system and conducting simulations to evaluate the effect of operation parameters, environmental conditions,
and design parameters on the performance of evaporator. An automotive air conditioning system primarily consists of four
components: the compressor, the condenser, the refrigerant controller, and the evaporator. The refrigerant flow in the
evaporator can be divided into two regions: the evaporating region and the superheat region. The refrigerant in the first
12
region is a two-phase flow, while the refrigerant in the latter region is in the state of superheated vapor. The air flowing
through the interior of the evaporator can also be divided into two zones: the unsaturated zone and the saturated zone.
Water vapor is condensed in the saturated zone while in the unsaturated zone, no water condenses. Because the refrigerant
flow and the airflow are perpendicular to each other, the distribution of refrigerant in the evaporating region and the
superheat region does not coincide with the distribution of air in the unsaturated zone and the saturated zone. This study
examines the effects of different design parameters, environmental conditions and operating parameters on the cooling
capacity and superheat of an air conditioning system. Design parameters include the length of the refrigerant channel, the
length of the air channel, and the thickness of the fins. Environmental conditions include the air inlet temperature and
absolute humidity. Operation conditions include the refrigerant inlet enthalpy, inlet air flow rate, and refrigerant mass flow
rate. Results of simulation demonstrated that fins with 50 micron meters width has the greatest cooling capacity for identical
outer dimensions; thicker or thinner fins only decreased cooling capacity. Under different outer dimensions, longer
refrigerant tubes and air channels created a greater cooling capacity. However, the increase in cooling capacity becomes less
and less if the refrigerant flow was fixed because the heat transfer capability of the gaseous refrigerant was limited. In this
study, an increase of 19% in cooling capacity can be reached as the length of refrigerant channels was increased, and the
increased length of the air channels can promote the cooling capacity by 22%. Besides, it was found in this study that a
decrease in the refrigerant inlet enthalpy, the inlet air flow rate, the air inlet temperature, and the inlet absolute humidity, or
an increase in the refrigerant mass flow rate, would extend the superheat region and decrease the refrigerant’s superheat. It
was also found that the cooling capacity of air conditioners is extremely sensitive to changes in the refrigerant mass flow rate
and the inlet enthalpy, and variations more than 50% were found in the operating ranges examined in this study. However,
changes in the inlet temperature, absolute humidity, and inlet air flow rate only resulted in variations between 10% and 20%
in the examined ranges of conditions. Finally, a correlation among these variables and the simulated cooling capacity was
obtained in this study, enabling the relevant researchers to evaluate automotive air conditioning performance under different
environmental conditions and operation parameters more easily.
Shen, C.C., & J.H. Lu (2014) Analysis of the Performance of the Evaporator of Automotive Air Conditioning System, INTERNATIONAL J.
OF AUTOMOTIVE TECHNOLOGY 15(1):19-38.
Exergy analysis of a domestic refrigerator using eco-friendly R290/R600a refrigerant mixture as an
alternative to R134a
Abstract - The aim of the present work is to bring out an exergy analysis of the hydrocarbon refrigerant mixture of
R290/R600a as an alternative to R134a on the performance of a domestic refrigerator which is originally designed to work
with R134a. The performance of both refrigerants was evaluated using an exergy analysis. The effects of evaporator
temperature on the coefficient of performance (COP), exergy loss, exergic efficiency, and efficiency defect in the four major
components of the system for R134a and R290/R600a mixture were experimentally investigated. The results obtained
showed that the COP of R290/R600a mixture was improved up to 28.5 % than that of R134a. The highest average exergic
efficiency of the system (42.1 %) was obtained using R290/R600a mixture at an evaporator temperature of 263 K (-10 C).
The overall efficiency defect in the refrigeration cycle working with R290/R600a mixture was consistently better than R134a.
Saravanakumar, R., & V. Selladurai (2014) Exergy analysis of a domestic refrigerator using eco-friendly R290/R600a refrigerant mixture
as an alternative to R134a, J. THERM. ANAL. CALORIM. 115:933-940.
Click Here to Return to the Table of Contents
TROPOSPHERIC OZONE
Ozone pollution: What can we see from space? A case study
Abstract - Due to its impact on environment, tropospheric ozone received particular attention since several decades.
Ground-based networks associated with regional chemical transport models are used to monitor and forecast surface ozone
concentrations, but coverage, representativeness, and accuracy issues remain important. Recent satellite observations have
demonstrated the capacity to probe tropospheric ozone, but there has been no explicit attempt to quantify their ability to
measure ozone pollution near ground. We propose here to assess the ability of ozone sounders to detect a photochemical
ozone pollution event that is supposed to be a favorable situation for satellite detection. We have chosen ozone pollution
event over Europe associated with a warm conveyor belt that efficiently transports photochemically produced ozone
13
upward. Ozone satellite products from Global Ozone Monitoring Experiment-2, Infrared Atmospheric Sounding
Interferometer (IASI), and Ozone Monitoring Instrument are analyzed here for their capacity to capture such an event. Also,
in situ observations and regional chemical-transport models show increasing ozone concentrations in the continental and
Mediterranean boundary layer and further transport to central Europe and Scandinavia associated with upward transport.
Satellite observations do not detect high ozone concentrations within the boundary layer due the weak sensitivity near the
surface. Nevertheless, we have shown that the IR sounder IASI was able to detect, qualitatively and quantitatively, the ozone
plume transported upward by the warm conveyor belt, suggesting that a quantification of upward transport of ozone
pollution could be possible using current satellite observations. This should encourage us to further explore approaches
more sensitive to surface ozone (such as the multispectral approach) and to prepare the next generation of still more
sensitive spaceborne instruments.
Foret, G., M. Eremenko, J. Cuesta, P. Sellitto, J. Barré, B. Gaubert, A. Coman, G. Dufour, X. Liu, M. Joly, C. Doche, & M.
Beekmann (2014) Ozone pollution: What can we see from space? A case study, JOURNAL OF GEOPHYSICAL RESEARCH:
ATMOSPHERES 119(13):8476-8499
Threat to future global food security from climate change and ozone air pollution
Abstract - Future food production is highly vulnerable to both climate change and air pollution with implications for global
food security. Climate change adaptation and ozone regulation have been identified as important strategies to safeguard food
production, but little is known about how climate and ozone pollution interact to affect agriculture, nor the relative
effectiveness of these two strategies for different crops and regions. Here we present an integrated analysis of the individual
and combined effects of 2000–2050 climate change and ozone trends on the production of four major crops (wheat, rice,
maize and soybean) worldwide based on historical observations and model projections, specifically accounting for ozone–
temperature co-variation. The projections exclude the effect of rising CO2, which has complex and potentially offsetting
impacts on global food supply. We show that warming reduces global crop production by >10% by 2050 with a potential to
substantially worsen global malnutrition in all scenarios considered. Ozone trends either exacerbate or offset a substantial
fraction of climate impacts depending on the scenario, suggesting the importance of air quality management in agricultural
planning. Furthermore, we find that depending on region some crops are primarily sensitive to either ozone (for example,
wheat) or heat (for example, maize) alone, providing a measure of relative benefits of climate adaptation versus ozone
regulation for food security in different regions.
Tai, A. P. K., M. Val Martin, & C. L. Heald (2014) Threat to future global food security from climate change and ozone air pollution,
NATURE CLIMATE CHANGE.
Click Here to Return to the Table of Contents
AEROSOL AIR POLLUTION
Personal and Indoor PM2.5 Exposure from Burning Solid Fuels in Vented and Unvented Stoves in a Rural
Region of China with a High Incidence of Lung Cancer
Abstract - The combustion of biomass and coal is the dominant source of household air pollution (HAP) in China, and
contributes significantly to the total burden of disease in the Chinese population. To characterize HAP exposure related to
solid fuel use and ventilation patterns, an exposure assessment study of 163 nonsmoking female heads of households
enrolled from 30 villages was conducted in Xuanwei and Fuyuan, two neighboring rural counties with high incidence of lung
cancer due to the burning of smoky coal (a bituminous coal, which in health evaluations is usually compared to smokeless
coal an anthracite coal available in some parts of the area). Personal and indoor 24-h PM2.5 samples were collected over two
consecutive days in each household, with approximately one-third of measurements retaken in a second season. The overall
geometric means (GM) of personal PM2.5 concentrations in Xuanwei and Fuyuan were 166 [Geometric Standard Deviation
(GSD):2.0] and 146 (GSD:1.9) μg/m3 , respectively, which were similar to the indoor PM2.5 air concentrations
[GM(GSD):162 (2.1) and 136 (2.0) μg/m3 , respectively]. Personal PM2.5 was moderately highly correlated with indoor
PM2.5 (Spearman r = 0.70, p < 0.0001). Burning wood or plant materials (tobacco stems, corncobs etc.) resulted in the
highest personal PM2.5 concentrations (GM:289 and 225 μg/m3 , respectively), followed by smoky coal, and smokeless coal
(GM:148 and 115 μg/m3, respectively). PM2.5 levels of vented stoves were 34−80% lower than unvented stoves and firepits
14
across fuel types. Mixed effect models indicated that fuel type, ventilation, number of windows, season, and burning time per
stove were the main factors related to personal PM2.5 exposure. Lower PM2.5 among vented stoves compared with
unvented stoves and firepits is of interest as it parallels the observation of reduced risks of malignant and nonmalignant lung
diseases in the region.
Hu, W., G. S. Downward, B. Reiss, J. Xu, B. A. Bassig, H. D. Hosgood, III, L. Zhang, W. J. Seow, G. Wu, R. S. Chapman, L.
Tian, F. Wei, R. Vermeulen, & Q. Lan (2014) Personal and Indoor PM2.5 Exposure from Burning Solid Fuels in Vented and Unvented
Stoves in a Rural Region of China with a High Incidence of Lung Cancer, ENVIRONMENTAL SCIENCE & TECHNOLOGY.
Variation in black carbon mass concentration over an urban site in the eastern coastal plains of the Indian
sub-continent
Abstract - Black carbon (BC) mass concentration variation has been studied, over a period of 2 years (June 2010–May 2012)
at Bhubaneswar. Daily, monthly and seasonal measurements revealed a clear winter maxima (5.6 μg/m3) of BC followed by
post-monsoon (4.05 μg/m3), monsoon (3.02 μg/m3) and premonsoon (2.46 μg/m3). Nighttime BC mass concentrations
have been found to be distinctly higher during winter followed by post-monsoon and monsoon. Investigations reveal that
the winter maxima are due to a stable atmospheric condition and long-range transport over the Indo-Gangetic Plain and
Western Asia. Local boundary layer dynamics and anthropogenic activities have been assumed to have a pronounced effect
on the diurnal cycle seasonally. Statistical analysis suggests significant variation of BC during the months and non-significant
during the days. The study also gives an insight into importance of BC study from health angle and suggests an assessment
and management framework. Source apportionment study suggests that BC mass concentration observed at Bhubaneswar is
generally dominated by fossil fuel combustion.
Mahapatra, P. S., S. Panda, N. Das, S. Rath, & T. Das (2014) Variation in black carbon mass concentration over an urban site in the
eastern coastal plains of the Indian sub-continent, THEOR APPL. CLIMATOL. 117:133-147.
Aerosols: The colour of smoke
Abstract - Particles of smoke from natural and human-made fires absorb sunlight and contribute to global warming.
Laboratory experiments suggest that smoke is often more absorbing than current numerical models of global climate assume.
Bellouin N. (2014) Aerosols: The colour of smoke, NATURE GEOSCIENCE
Characterization of carbonaceous aerosols over Delhi in Ganga basin: seasonal variability and possible
sources
Abstract - The mass concentration of carbonaceous species, organic carbon (OC), and elemental carbon (EC) using a
semicontinuous thermo-optical EC-OC analyzer, and black carbon (BC) using an Aethalometer were measured
simultaneously at an urban mega city Delhi in Ganga basin from January 2011 to May 2012. The concentrations of OC, EC,
and BC exhibit seasonal variability, and their concentrations were ∼2 times higher during winter (OC 38.1±17.9 μg m−3, EC
15.8±7.3 μgm−3, and BC 10.1±5.3 μgm−3) compared to those in summer (OC 14.1±4.3 μg m−3, EC 7.5±1.5 μg m−3, and
BC 4.9±1.5 μg m−3). A significant correlation between OC and EC (R=0.95, n=232) indicate their common emission
sources with relatively lower OC/EC ratio (range 1.0–3.6, mean 2.2±0.5) suggests fossil fuel emission as a major source of
carbonaceous aerosols over the station. On average, mass concentration of EC was found to be ∼38 % higher than BC
during the study period. The measured absorption coefficient (babs) was significantly correlatedwith EC, suggesting EC as a
major absorbing species in ambient aerosols at Delhi. Furthermore, the estimated mass absorption efficiency (σabs) values
are similar during winter (5.0±1.5 m2 g−1) and summer (4.8± 2.8 m2 g−1). Significantly high aerosol loading of
carbonaceous species emphasize an urgent need to focus on air quality management and proper impact assessment on health
perspective in these regions.
Srivastava, A. K., D. S. Bisht, K. Ram, S. Tiwari, & Manoj K. Srivastava (2014) Characterization of carbonaceous aerosols over Delhi
in Ganga basin: seasonal variability and possible sources, ENVIRON. SCI. POLLUT. RES. 21:8610-8619.
The effect of aerosol optical depth on rainfall with reference to meteorology over metro cities in India
Abstract - Rainfall is a key link in the global water cycle and a proxy for changing climate; therefore, proper assessment of
the urban environment’s impact on rainfall will be increasingly important in ongoing climate diagnostics and prediction.
Aerosol optical depth (AOD) measurements on the monsoon seasons of the years 2008 to 2010 were made over four metro
15
regional hotspots in India. The highest average of AOD was in the months of June and July for the four cities during 3 years
and lowest was in September. Comparing the four regions, Kolkata was in the peak of aerosol contamination and Chennai
was in least. Pearson correlation was made between AOD with climatic parameters. Some changes in the parameters were
found during drought year. Temperature, cloud parameters, and humidity play an important role for the drought conditions.
The role of aerosols, meteorological parameters, and their impacts towards the precipitation during the monsoon was
studied.
Gunaseelan I., B. V. Bhaskar, & K. Muthuchelian (2014) The effect of aerosol optical depth on rainfall with reference to meteorology over
metro cities in India, ENVIRON. SCI. POLLUT. RES. 21:8188-8197.
Aerosol effects on cirrus through ice nucleation in the Community Atmosphere Model CAM5 with a
statistical cirrus scheme
Abstract - A statistical cirrus scheme that tracks ice saturation ratio in the clear-sky and cloudy portion of a grid box
separately has been implemented into the Community Atmosphere Model CAM5 to provide a consistent treatment of ice
nucleation and cloud formation. Simulated ice supersaturation and ice crystal number concentrations strongly depend on the
number concentrations of heterogeneous ice nuclei (IN), subgrid temperature formulas, and the number concentration of
sulfate particles participating in homogeneous freezing, while simulated ice water content is insensitive to these
perturbations. Allowing 1–10% of dust particles to serve as heterogeneous IN is found to produce ice supersaturation in
better agreement with observations. Introducing a subgrid temperature perturbation based on long-term aircraft observations
produces a better hemispheric contrast in ice supersaturation compared to observations. Heterogeneous IN from dust
particles alter the net radiative fluxes at the top of atmosphere (TOA) (−0.24 to −1.59 W m−2) with a significant clear-sky
longwave component (0.01 to −0.55 W m−2). Different cirrus treatments significantly perturb the net TOA anthropogenic
aerosol forcing from −1.21 W m−2 to −1.54 W m−2, with a standard deviation of 0.10 W m−2. Aerosol effects on cirrus
exert an even larger impact on the atmospheric component of the radiative fluxes (2 or 3 times the changes in the TOA
radiative fluxes) and therefore through the fast atmosphere response on the hydrological cycle. This points to the urgent
need to quantify aerosol effects on cirrus through ice nucleation and how these further affect the hydrological cycle.
Wang, M., X. Liu, K. Zhang, & J. M. Comstock (2014) Aerosol effects on cirrus through ice nucleation in the Community Atmosphere
Model CAM5 with a statistical cirrus scheme, JOURNAL OF ADVANCED IN MODELING EARTH SYSTEMS (Early View)
Decreased monsoon precipitation in the Northern Hemisphere due to anthropogenic aerosols
Abstract - The Northern Hemisphere monsoons are an integral component of Earth’s hydrological cycle and affect the lives
of billions of people. Observed precipitation in the monsoon regions underwent substantial changes during the second half
of the 20th century, with drying from the 1950s to mid-1980s and increasing precipitation in recent decades. Modeling
studies suggest anthropogenic aerosols has been a key factor driving changes in tropical and monsoon precipitation. Here we
apply detection and attribution methods to determine whether observed changes are driven by human influences using
fingerprints of individual forcings (i.e. greenhouse gas, anthropogenic aerosol and natural) derived from climate models. The
results show that the observed changes can only be explained when including the influence of anthropogenic aerosols, even
after accounting for internal climate variability. Anthropogenic aerosol, not greenhouse gas or natural forcing, has been the
dominant influence on Northern Hemisphere monsoon precipitation over the The Northern Hemisphere monsoons are an
integral component of Earth’s hydrological cycle and affect the lives of billions of people. Observed precipitation in the
monsoon regions underwent substantial changes during the second half of the 20th century, with drying from the 1950s to
mid-1980s and increasing precipitation in recent decades. Modeling studies suggest anthropogenic aerosols has been a key
factor driving changes in tropical and monsoon precipitation. Here we apply detection and attribution methods to determine
whether observed changes are driven by human influences using fingerprints of individual forcings (i.e. greenhouse gas,
anthropogenic aerosol and natural) derived from climate models. The results show that the observed changes can only be
explained when including the influence of anthropogenic aerosols, even after accounting for internal climate variability.
Anthropogenic aerosol, not greenhouse gas or natural forcing, has been the dominant influence on Northern Hemisphere
monsoon precipitation over the second half of the 20th century.
Polson, D., M. Bollasina, G. C. Hegerl, & L. J. Wilcox (2014) Decreased monsoon precipitation in the Northern Hemisphere
due to anthropogenic aerosols, Geophysical Research Letters (Early View).
16
Observational evidence of fire-driven reduction of cloud fraction in tropical Africa
Abstract - Anthopogenic savanna fires in sub-Saharan Africa emit smoke that affects cloudiness in the region. We measured
the cloud response to fire aerosols using aerosol data from the Multi-angle Imaging SpectroRadiometer (MISR) and cloud
fraction data from the morning and afternoon overpasses of the Moderate Resolution Imaging Spectroradiometer (MODIS)
instrument. Considering the same cloud scene from the morning and afternoon satellite observations allowed us to observe
the temporal relationship between clouds and aerosols. Level 2 data from 35 individual scenes during the fire season
(December) between 2006 and 2010 were analyzed to quantify changes in MODIS cloud fraction from morning (10:30 A.M.
local time) to afternoon (1:30 P.M. local time) in the presence of different morning aerosol burdens (from MISR). We
controlled for the local meteorology by analyzing scenes from November, when fire activity and aerosol optical depth were
low but cloud fraction and meteorological variables (boundary layer height, pressure, total column water vapor, temperature,
and convective available potential energy) were similar to those of the fire season. High-fire-driven aerosol optical depth
(AOD) was associated with reduced cloud fraction in both the raw and meteorologically normalized data. Fire aerosols
reduced the relative cloud fraction in all sky conditions, but the effects were progressively larger in high-AOD conditions.
These results may provide observational evidence of the semidirect cloud decimation effect in tropical regions and suggest a
positive feedback loop between anthropogenic burning and cloudiness—where more aerosols lead to decreased clouds,
increased surface exposure and drying, more fire, and thus more aerosols—which is consistent with previous studies linking
smoke aerosols to reduced cloudiness and vice versa.
Tosca, M. G., D. J. Diner, M. J. Garay, & O. V. Kalashnikova (2014) Observational evidence of fire-driven reduction of cloud fraction in
tropical Africa, JOURNAL OF GEOPHYSICAL RESEARCH: ATMOSPHERES 119(13).
Climate impacts of changing aerosol emissions since 1996
Abstract - Increases in Asian aerosol emissions have been suggested as one possible reason for the hiatus in global
temperature increase during the past 15 years. We study the effect of sulphur and black carbon (BC) emission changes
between 1996 and 2010 on the global energy balance. We find that the increased Asian emissions have had very little regional
or global effects, while the emission reductions in Europe and the U.S. have caused a positive radiative forcing. In our
simulations, the global-mean aerosol direct radiative effect changes by 0.06 W/m2 during 1996 to 2010, while the effective
radiative forcing (ERF) is 0.42 W/m2. The rather large ERF arises mainly from changes in cloudiness, especially in Europe.
In Asia, the BC warming due to sunlight absorption has largely offset the cooling caused by sulphate aerosols. Asian BC
concentrations have increased by a nearly constant fraction at all altitudes, and thus, they warm the atmosphere also in
cloudy conditions.
Kühn, T., A.-I. Partanen, A. Laakso, Z. Lu, T. Bergman, S. Mikkonen, H. Kokkola, H. Korhonen,P. Räisänen, D. G. Streets,
S. Romakkaniemi, & A. Laaksonen (2014) Climate impacts of changing aerosol emissions since 1996, GEOPHYSICAL RESEARCH
LETTERS 41(13):4711-4718.
Remote sensing of aerosols in the Arctic for an evaluation of global climate model simulations
Abstract - In this study Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua retrievals of aerosol optical
thickness (AOT) at 555 nm are compared to Sun photometer measurements from Svalbard for a period of 9 years. For the
642 daily coincident measurements that were obtained, MODIS AOT generally varies within the predicted uncertainty of the
retrieval over ocean (ΔAOT = ±0.03 ± 0.05 · AOT). The results from the remote sensing have been used to examine the
accuracy in estimates of aerosol optical properties in the Arctic, generated by global climate models and from in situ
measurements at the Zeppelin station, Svalbard. AOT simulated with the Norwegian Earth System Model/Community
Atmosphere Model version 4 Oslo global climate model does not reproduce the observed seasonal variability of the Arctic
aerosol. The model overestimates clear-sky AOT by nearly a factor of 2 for the background summer season, while tending to
underestimate the values in the spring season. Furthermore, large differences in all-sky AOT of up to 1 order of magnitude
are found for the Coupled Model Intercomparison Project phase 5 model ensemble for the spring and summer seasons.
Large differences between satellite/ground-based remote sensing of AOT and AOT estimated from dry and humidified
scattering coefficients are found for the subarctic marine boundary layer in summer.
Glantz, P., A. Bourassa, A. Herber, T. Iversen, J. Karlsson, A. Kirkevåg, M. Maturilli, Ø. Seland, K. Stebel, H. Struthers, M.
Tesche, & L. Thomason (2014) Remote sensing of aerosols in the Arctic for an evaluation of global climate model simulations, JOURNAL OF
GEOPHYSICAL RESEARCH: ATMOSPHERES 119(13).
17
Click Here to Return to the Table of Contents
AIR POLLUTION & HEALTH
Short-term effects of air pollution on a range of cardiovascular events in England and Wales: casecrossover analysis of the MINAP database, hospital admissions and mortality
Abstract - Objective To inform potential pathophysiological mechanisms of air pollution effects on cardiovascular disease
(CVD), we investigated short-term associations between ambient air pollution and a range of cardiovascular events from
three national databases in England and Wales. Methods Using a time-stratified case-crossover design, over 400 000
myocardial infarction (MI) events from the Myocardial Ischaemia National Audit Project (MINAP) database, over 2 million
CVD emergency hospital admissions and over 600 000 CVD deaths were linked with daily mean concentrations of carbon
monoxide (CO), nitrogen dioxide (NO2), particulate matter less than 10 μm in aerodynamic diameter (PM10), particulate
matter less than 2.5 μm in aerodynamic diameter (PM2.5) and sulfur dioxide (SO2), and daily maximum of 8-hourly running
mean of O3 measured at the nearest air pollution monitoring site to the place of residence. Pollutant effects were modelled
using lags up to 4 days and adjusted for ambient temperature and day of week. Results For mortality, no CVD outcome
analysed was clearly associated with any pollutant, except for PM2.5 with arrhythmias, atrial fibrillation and pulmonary
embolism. With hospital admissions, only NO2 was associated with a raised risk: CVD 1.7% (95% CI 0.9 to 2.6), non-MI
CVD 2.0% (1.1 to 2.9), arrhythmias 2.9% (0.6 to 5.2), atrial fibrillation 2.8% (0.3 to 5.4) and heart failure 4.4% (2.0 to 6.8)
for a 10th–90th centile increase. With MINAP, only NO2 was associated with an increased risk of MI, which was specific to
non-ST-elevation myocardial infarction (non-STEMIs): 3.6% (95% CI 0.4 to 6.9). Conclusions This study found no clear
evidence for pollution effects on STEMIs and stroke, which ultimately represent thrombogenic processes, though it did for
pulmonary embolism. The strongest associations with air pollution were observed with selected non-MI outcomes.
Milojevic, A., P. Wilkinson, B. Armstrong, K. Bhaskaran, L. Smeeth, & S. Hajat (2014) Short-term effects of air pollution on a range
of cardiovascular events in England and Wales: case-crossover analysis of the MINAP database, hospital admissions and mortality, HEART
100:1093-1098.
PM2.5 Constituents and Hospital Emergency-Room Visits in Shanghai, China
Abstract - Although ambient PM2.5 has been linked to adverse health effects, the chemical constituents that cause harm are
largely unclear. Few prior studies in a developing country have reported the health impacts of PM 2.5 constituents. In this
study, we examined the short-term association between PM2.5 constituents and emergency room visits in Shanghai, China.
We measured daily concentrations of PM2.5, organic carbon (OC), elemental carbon (EC), and eight water-soluble ions
between January 1, 2011 and December 31, 2012. We analyzed the data using overdispersed generalized linear Poisson
models. During our study period, the mean daily average concentration of PM2.5 in Shanghai was 55 μg/m3. Major
contributors to PM2.5 mass included OC, EC, sulfate, nitrate, and ammonium. For a 1-day lag, an interquartile range
increment in PM2.5 mass (36.47 μg/m3) corresponded to 0.57% [95% confidence interval (CI): 0.13%, 1.01%] increase of
emergency room visits. In all the three models used, we found significant positive associations of emergency room visits with
OC and EC. Our findings suggest that PM2.5 constituents from the combustion of fossil fuel (e.g., OC and EC) may have an
appreciable influence on the health impact attributable to PM2.5.
Qiao, L., J. Cai, H. Wang, W. Wang, M. Zhou, S. Lou, R. Chen, H. Dai, C. Chen, & H. Kan (2014) PM2.5 Constituents and
Hospital Emergency-Room Visits in Shanghai, China, ENVIRONMENTAL SCIENCE AND TECHNOLOGY.
Burning in agricultural landscapes: an emerging natural and human issue in China
Abstract - Burning is one of the most widely used methods for removing crop residues during harvest seasons. It cleans
fields faster and costs less in comparison to other residue removal methods. Agricultural burning, however, has been recently
limited or banned during harvest seasons in China, mainly due to the air quality and human health concerns raised from its
use. This paper reviews recent studies on the burning of agricultural landscapes in China to understand the natural
(environmental and ecological) and human (economic and social) impacts and identifies uncertainties, gaps, and future
research needs. The total annual crop straw output in China is more than 600 billon kg, with about 110, 130, and 230 billion
kg coming from rice, wheat, and corn, respectively. Agricultural burning removes about one-fourth of total crop straw and
emits about 140–240, 1.6–2.2, and 0.5–0.14 billion kg of CO2, PM2.5, and black carbon, respectively. Agricultural burning
accounts for up to half of the total PM10 concentrations in the major burning regions during harvesting periods. Burning
18
emissions contribute to regional haze and smog events. Therefore, limiting or banning agricultural burning is a necessary
measure for reducing air pollution in China. The estimations of total burned crop straw amounts and emission factors are
the major uncertainty sources for emission estimates. More studies are needed to better describe the smoke plume rise,
dispersion, and interactions with weather and climate and to simulate the ecological impacts of agricultural burning. Effective
alternatives need to be explored in order to provide solutions for farmers to remove agricultural residues in the wake of the
burning ban.
Shi, T., Y. Liu, L. Zhang, L. Hao, & Z. Gao (2014) Burning in agricultural landscapes: an emerging natural and human issue in China,
LANDSCAPE ECOL..
Ambient Air Pollution and Type 2 Diabetes Mellitus: A Systematic Review of Epidemiologic Research
Abstract - Recent experimental and epidemiologic studies have suggested air pollution as a new risk factor for type 2
diabetes mellitus (T2DM).We conducted a systematic review of the epidemiologic studies on the association of air pollution
with T2DM and related outcomes published by December 2013. We identified 22 studies: six prospective studies on incident
T2DM; two prospective study on diabetes mortality; four cross-sectional studies on prevalent T2DM; seven ecological
studies on mortality or morbidity from diabetes; and three studies on glucose or insulin levels. The evidence of the
association between long-term exposure to fine particles (PM2.5) and the risk of T2DM is suggestive. The summary hazard
ratio of the association between long-term PM2.5 exposure and incident T2DMwas 1.11 (95%CI 1.03, 1.19) for a 10 μg/m3
increase. The evidence on the association between long-term traffic-related exposure (measured by nitrogen dioxide or
nitrogen oxides) and the risk of T2DM was also suggestive, although most studies were conducted in women. For short-term
effects of air pollution on diabetes mortality or hospital/emergency admissions, we conclude that the evidence is not
sufficient to infer a causal relationship. Because most studies were conducted in North America or in Europe where
exposure levels are relatively low, more studies are needed in recently urbanized areas in Asia and Latin America where air
pollution levels are much higher and T2DM is an emerging public health concern.
Park, S. K., & W. Wang (2014) Ambient Air Pollution and Type 2 Diabetes Mellitus: A Systematic Review of Epidemiologic Research,
CURR. ENVIR. HEALTH RPT..
Particulate Matter Air Pollution Exposure, Distance to Road, and Incident Lung Cancer in the Nurses’
Health Study Cohort
Abstract - Background: A body of literature has developed suggesting an elevated risk of lung cancer associated with
particulate matter and traffic-related pollutants. Objective: We examined the relation of lung cancer incidence with long-term
residential exposures to ambient particulate matter and residential distance to roadway, as a proxy for traffic-related
exposures. Methods: For participants in the Nurses' Health Study, a nationwide prospective cohort of women, we estimated
72 month average exposures to PM2.5, PM2.5-10, and PM10 and residential distance to road. Follow-up for incident cases
of lung cancer occurred from 1994 to 2010. Cox proportional hazards models were adjusted for potential confounders.
Effect modification by smoking status was examined. Results: During 1,510,027 person years, 2,155 incident cases of lung
cancer were observed among 103,650 participants. In fully adjusted models, a 10 µg/m3 increase in 72 month average PM10
(HR = 1.04; 95% CI: 0.95, 1.14), PM2.5 (HR = 1.06; 95% CI: 0.91, 1.25), or PM2.5-10 (HR = 1.05; 95% CI: 0.92, 1.20) was
positively associated with lung cancer. When the cohort was restricted to never smokers and former smokers who had quit at
least 10 years ago, the associations appeared to increase and were strongest for PM2.5 [(PM10: HR = 1.15; 95% CI:
1.00,1.32) (PM2.5: HR = 1.37; 95% CI: 1.06,1.77) (PM2.5-10: HR = 1.11; 95% CI: 0.90,1.37)]. Results were most elevated
when restricted to the most prevalent subtype, adenocarcinomas. Risks with roadway proximity were less consistent.
Conclusions: Our findings support those from other studies indicating increased risk of incident lung cancer associated with
ambient PM exposures, especially among never and long-term former smokers.
Puett, R. C., J. E. Hart, J. D. Yanosky, D. Spiegelman, M. Wang, J. A. Fisher, B. Hong, & F. Laden (2014) Particulate Matter
Air Pollution Exposure, Distance to Road, and Incident Lung Cancer in the Nurses’ Health Study Cohort, ENVIRONMENTAL HEALTH
PERSPECTIVES.
Click Here to Return to the Table of Contents
AGRICULTURE
19
Invited Review: Enteric methane in dairy cattle production: Quantifying the opportunities and impact of
reducing emissions
Abstract - Many opportunities exist to reduce enteric methane (CH4) and other greenhouse gas (GHG) emissions per unit
of product from ruminant livestock. Research over the past century in genetics, animal health, microbiology, nutrition, and
physiology has led to improvements in dairy production where intensively managed farms have GHG emissions as low as 1
kg of CO2 equivalents (CO2e)/kg of energy-corrected milk (ECM), compared with >7 kg of CO2e/kg of ECM in extensive
systems. The objectives of this review are to evaluate options that have been demonstrated to mitigate enteric CH4
emissions per unit of ECM (CH4/ECM) from dairy cattle on a quantitative basis and in a sustained manner and to integrate
approaches in genetics, feeding and nutrition, physiology, and health to emphasize why herd productivity, not individual
animal productivity, is important to environmental sustainability. A nutrition model based on carbohydrate digestion was
used to evaluate the effect of feeding and nutrition strategies on CH4/ECM, and a meta-analysis was conducted to quantify
the effects of lipid supplementation on CH4/ECM. A second model combining herd structure dynamics and production
level was used to estimate the effect of genetic and management strategies that increase milk yield and reduce culling on
CH4/ECM. Some of these approaches discussed require further research, but many could be implemented now. Past efforts
in CH4 mitigation have largely focused on identifying and evaluating CH4 mitigation approaches based on nutrition, feeding,
and modifications of rumen function. Nutrition and feeding approaches may be able to reduce CH4/ECM by 2.5 to 15%,
whereas rumen modifiers have had very little success in terms of sustained CH4 reductions without compromising milk
production. More significant reductions of 15 to 30% CH4/ECM can be achieved by combinations of genetic and
management approaches, including improvements in heat abatement, disease and fertility management, performanceenhancing technologies, and facility design to increase feed efficiency and life-time productivity of individual animals and
herds. Many of the approaches discussed are only partially additive, and all approaches to reducing enteric CH4 emissions
should consider the economic impacts on farm profitability and the relationships between enteric CH4 and other GHG.
Knapp, J. R., G. L. Laur, P. A. Vadas, W. P. Weiss, & J. M. Tricarico (2014) Invited Review: Enteric methane in dairy cattle
production: Quantifying the opportunities and impact of reducing emissions, JOURNAL OF DAIRY SCIENCE 97(6):3231-3261.
Archaeal abundance in post-mortem ruminal digesta may help predict methane emissions from beef cattle
Abstract - Methane produced from 35 Aberdeen-Angus and 33 Limousin cross steers was measured in respiration
chambers. Each group was split to receive either a medium- or high-concentrate diet. Ruminal digesta samples were
subsequently removed to investigate correlations between methane emissions and the rumen microbial community, as
measured by qPCR of 16S or 18S rRNA genes. Diet had the greatest influence on methane emissions. The high-concentrate
diet resulted in lower methane emissions (P < 0.001) than the medium-concentrate diet. Methane was correlated, irrespective
of breed, with the abundance of archaea (R = 0.39), bacteria (−0.47), protozoa (0.45), Bacteroidetes (−0.37)
and Clostridium Cluster XIVa (−0.35). The archaea:bacteria ratio provided a stronger correlation (0.49). A similar correlation
was found with digesta samples taken 2–3 weeks later at slaughter. This finding could help enable greenhouse gas emissions
of large animal cohorts to be predicted from samples taken conveniently in the abattoir.
Wallace, R. J., J. A. Rooke, C-A Duthie, J. J. Hyslop, D. W. Ross, N. McKain, S. M. de Souza, T. J. Snelling, A. Waterhouse,
& R. Roehe (2014) Archaeal abundance in post-mortem ruminal digesta may help predict methane emissions from beef cattle, SCIENTIFIC
REPORTS 4(5892).
Simulation of biomass burning aerosols mass distributions and their direct and semi-direct effects over
South Africa using a regional climate model
Abstract - In this study, we examine the mass distributions, direct and semi-direct effects of different biomass burning
aerosols (BBAs) over South Africa using the 12-year runs of the Regional Climate Model (RegCM4). The results were
analyzed and presented for the main BB season (July–October). The results show that Mpumalanga, KwaZulu Natal and the
eastern parts of Limpopo are the main local source areas of BBAs in South Africa. In comparison to carbonaceous aerosols,
BB-induced sulfate aerosol mass loading and climatic effects were found to be negligible. All carbonaceous aerosols reduce
solar radiation at the surface by enhancing local atmospheric radiative heating. The climatic feedback caused by BBAs,
resulted in changes in background aerosol concentrations. Thus, on a regional scale, climatic effects of BBAs were also
found in areas far away from the BBA loading zones. The feedback mechanisms of the climate system to the aerosol
radiative effects resulted in both positive and negative changes to the low-level columnar averaged net atmospheric radiative
heating rate (NAHR). Areas that experienced an NAHR reduction showed an increase in cloud cover (CC). During the
NAHR enhancement, CC over arid areas decreased; whereas CC over the wet/semi-wet regions increased. The changes in
20
surface temperature (ST) and surface sensible heat flux are more closely correlated with BBA semi-direct effects induced CC
alteration than their direct radiative forcing. Furthermore, decreases (or increases) in ST, respectively, lead to the reductions
(and enhancements) in boundary layer height and the vice versa on surface pressure. The direct and semi-direct effects of
BBAs also jointly promoted a reduction and rise in surface wind speed that was spatially highly variable. Overall, the results
suggest that the CC change induced by the presence of radiatively interactive BBAs is important to determine alterations in
other climatic variables.
Tesfaye, M., J. Botai, V. Sivakumar, & G. Mengistu Tsidu (2014) Simulation of biomass burning aerosols mass distributions and their
direct and semi-direct effects over South Africa using a regional climate model, METEROROL. ATMOS. PHYS. 125:177-195.
Sealing Rice Field Boundaries in Bangladesh: A Pilot Study Demonstrating Reductions in Water Use,
Arsenic Loading to Field Soils, and Methane Emissions from Irrigation Water
Abstract - Irrigation of rice fields in Bangladesh with arseniccontaminated and methane-rich groundwater loads arsenic into
field soils and releases methane into the atmosphere. We tested the water-savings potential of sealing field bunds (raised
boundaries around field edges) as a way to mitigate these negative outcomes. We found that, on average, bund sealing
reduced seasonal water use by 52 ± 17% and decreased arsenic loading to field soils by 15 ± 4%; greater savings in both
water use and arsenic loading were achieved in fields with larger perimeter-to area ratios (i.e., smaller fields). Our study is the
first to quantify emission of methane from irrigation water in Bangladesh, a currently unaccounted-for methane source.
Irrigation water applied to unsealed fields at our site emits 18 to 31 g of methane per square-meter of field area per season,
potentially doubling the atmospheric input of methane from rice cultivation. Bund sealing reduced the emission of methane
from irrigation water by 4 to 19 g/m2. While the studied outcomes of bund sealing are positive and compelling, widespread
implementation of the technique should consider other factors, such as effect on yields, financial costs, and impact on the
hydrologic system. We provide an initial and preliminary assessment of these implementation factors.
Neumann, R. B., L. E. Pracht, M. L. Polizzotto, A. B. M. Badruzzaman, & M. A. Ali (2014) Sealing Rice Field Boundaries in
Bangladesh: A Pilot Study Demonstrating Reductions in Water Use, Arsenic Loading to Field Soils, and Methane Emissions from Irrigation
Water, ENVIRONMENTAL SCIENCE & TECHNOLOGY.
Click Here to Return to the Table of Contents
BIOMASS BURNING & COOKING AND HEATING
Overuse of wood-based bioenergy in selected sub-Saharan Africa countries: review of unconstructive
challenges and suggestions
Abstract - Excessive wood consumption for energy and over-dependence on fossil fuel-based energy are fundamental issues
of importance regarding the destruction of environmental sanity. In this respect, international communities are seeking to
explore opportunities on how to encourage aggressive deployment of technologies for clean and sustainable development
and possibly renewable. The Kyoto protocol on climate change meeting in 1997 with about 160 countries in attendance has
been used as one of the platform of discourse on carbon emissions reduction strategies. Advocated strategies agreed include
increase in renewable energy consumption via modern techniques. Massive deployment of renewable energy systems on a
global scale will ensure a reasonable displacement of oil based energy production which is the main source of anthropogenic
Greenhouse Gases. In sub-Saharan Africa, limited access to modern energy in the region has stepped-up reliance on
bioenergy consumption in form of wood fuel and charcoal resulting to attendant effects on human health, environment and
the biodiversity in general. In view of the foregoing, this study presents a review on the current situations of unconstructive
effects in the overuse of fuel wood and its charcoal derivative for energy consumption in three selected sub-Saharan African
countries; Nigeria, Ghana and Uganda. In conclusion, suggestions on how to confront the challenges associated with the
over-exploitation conditions of fuel wood in the region are put forward. The suggestions could be part of the pursuit to
increase electricity availability, reliability and security with lower level of emissions in the region.
Mohammed, Y. S., N. Bashir, & M. W. Mustafa (2014) Overuse of wood-based bioenergy in selected sub-Saharan Africa countries: review
of unconstructive challenges and suggestions, JOURNAL OF CLEARER PRODUCTION (in press).
21
Design and performance assessment of a rice husk fueled stove for household cooking in a typical sub-Saharan
setting
Abstract - This study presents the design and development of a rice-husk-fuelled cookstove to improve poor people's
energy access in developing countries. The availability of rice husk, an agricultural by-product currently without any use,
neither value, on many markets, has suggested recovering this biomass for household-cooking purposes. According to typical
rural socio-technical constraints, a prototype of rice husk burner has been designed. After testing various configurations, a
crude-earth structure with a metal-net fuel reactor, placed inside the combustion chamber, resulted to be the most promising
lay-out. A chimney induces the air flows, necessary for operation, in the combustion chamber, while eliminating harmful
smokes from the living environment. The chimney also prevents the use of electrical fans, which may not result
appropriately for many rural contexts. Performance results are presented, together with emission data and a safety
assessment. Results from Water Boiling Tests (average thermal efficiency 18%) and Controlled Cooking Tests (specific
consumption 4.2 MJ per kg of cooked food) show how this technology could represent a viable alternative to three-stone
fires and other rudimentary cooking systems, allowing the recovery of energy from a waste biomass. Evidences from the
safety assessment and the indoor CO monitoring demonstrate the absence of hazards in the domestic use of the stove. The
study is completed by an economic analysis that accounts for the local feasibility and affordability of this specific solution in
a given context.
Parmigiani S. P., F. Vitali, A. M. Lezzi, & M. Vaccari (2014) Design and performance assessment of a rice husk fueled stove for household
cooking in a typical sub-Saharan setting, ENERGY FOR SUSTAINABLE DEVELOPMENT 23:15-24.
Effect of gradients in biomass burning aerosol on shallow cumulus convective circulations
Abstract - This study examines the effect of spatial gradients in biomass burning (BB) aerosol on mesoscale circulations and
clouds in the Amazon through high-resolution numerical modeling over areas of 30 km – 60 km. Inhomogeneous horizontal
distribution of BB aerosol results in differential surface heat fluxes and radiative heating of the air, which generates
circulation patterns that strongly influence cloud formation. The influence on air circulation and cumulus cloud formation
depends on the BB aerosol loading, its vertical location, and the width of the plume. Plumes that reside at higher altitudes (~
1.5 km altitude) produce monotonic responses to aerosol loading whereas the response to plumes close to the surface
changes non-monotonically with plume width and aerosol loading. Sensitivity tests highlight the importance of interactive
calculations of surface latent and heat fluxes with a coupled land surface model. In the case of the plume residing at higher
altitude, failure to use interactive fluxes results in a reversal of the circulation whereas for the plume residing nearer the
surface, the interactive surface model weakens the circulation. The influence of the BB aerosol on heating patterns,
circulations, surface fluxes, and resultant cloud amount prevails over the BB aerosol-cloud microphysical influences
Lee S.-S., G. Feingold, A. McComiskey, T. Yamaguchi, I. Koren, J. V. Martins, & H. Yu (2014) Effect of gradients in biomass
burning aerosol on shallow cumulus convective circulations, JOURNAL OF GEOPHYSICAL RESEARCH: ATMOSPHERES (Early View).
Soot superaggregates from flaming wildfires and their direct radiative forcing
Abstract - Wildfires contribute significantly to global soot emissions, yet their aerosol formation mechanisms and resulting
particle properties are poorly understood and parameterized in climate models. The conventional view holds that soot is
formed via the cluster-dilute aggregation mechanism in wildfires and emitted as aggregates with fractal dimension Df < 1.8
mobility diameter Dm # 1 mm, and aerodynamic diameter Da# 300 nm. Here we report the ubiquitous presence of soot
superaggregates (SAs) in the outflow from a major wildfire in India. SAs are porous, low-density aggregates of cluster-dilute
aggregates with characteristic Df< 2.6, Dm . 1 mm, and Da# 300 nm that form via the cluster-dense aggregation
mechanism. We present additional observations of soot SAs in wildfire smoke-laden air masses over Northern California,
New Mexico, and Mexico City. We estimate that SAs contribute, per unit optical depth, up to 35% less atmospheric warming
than freshly-emitted (Df < 1.8) aggregates, and <90% more warming than the volume-equivalent spherical soot particles
simulated in climate models.
Chakrabarty, R. K., N. D. Beres, H. Moosmuller, S. China, C. Mazzoleni, M. K. Dubey, L. Liu, & M. I. Mishchenko (2014)
Soot superaggregates from flaming wildfires and their direct radiative forcing, NATURE SCIENTIFIC REPORTS 4:5508.
Brownness of organics in aerosols from biomass burning linked to their black carbon content
Abstract - Atmospheric particulate matter plays an important role in the Earth’s radiative balance. Over the past two
decades, it has been established that a portion of particulate matter, black carbon, absorbs significant amounts of light and
22
exerts a warming effect rivalling that of anthropogenic carbon dioxide1, Most climate models treat black carbon as the sole
light-absorbing carbonaceous particulate. However, some organic aerosols, dubbed brown carbon and mainly associated with
biomass burning emissions, also absorbs light. Unlike black carbon, whose light absorption properties are well understood,
brown carbon comprises a wide range of poorly characterized compounds that exhibit highly variable absorptivities, with
reported values spanning two orders of magnitude. Here we present smog chamber experiments to characterize the effective
absorptivity of organic aerosol from biomass burning under a range of conditions. We show that brown carbon in emissions
from biomass burning is associated mostly with organic compounds of extremely low volatility11. In addition, we find that
the effective absorptivity of organic aerosol in biomass burning emissions can be parameterized as a function of the ratio of
black carbon to organic aerosol, indicating that aerosol absorptivity depends largely on burn conditions, not fuel type. We
conclude that brown carbon from biomass burning can be an important factor in aerosol radiative forcing.
Saleh, R., E. S. Robinson, D. S. Tkacik, A. T. Ahern, S. Liu, A. C. Aiken, R. C. Sullivan, A. A. Presto, M. K. Dubey, R. J.
Yokelson, N. M. Donahue, & A. L. Robinson (2014) Brownness of organics in aerosols from biomass burning linked to their black carbon
content, NATURE GEOSCIENCE (Early View).
Effects of biomass burning on climate, accounting for heat and moisture fluxes, black and brown carbon,
and cloud absorption effects
Abstract - This paper examines the effects on climate and air pollution of open biomass burning (BB) when heat and
moisture fluxes, gases and aerosols (including black and brown carbon, tar balls, and reflective particles), cloud absorption
effects (CAEs) I and II, and aerosol semidirect and indirect effects on clouds are treated. It also examines the climate
impacts of most anthropogenic heat and moisture fluxes (AHFs and AMFs). Transient 20 year simulations indicate BB may
cause a net global warming of ~0.4 K because CAE I (~32% of BB warming), CAE II, semidirect effects, AHFs (~7%),
AMFs, and aerosol absorption outweigh direct aerosol cooling and indirect effects, contrary to previous BB studies that did
not treat CAEs, AHFs, AMFs, or brown carbon. Some BB warming can be understood in terms of the anticorrelation
between instantaneous direct radiative forcing (DRF) changes and surface temperature changes in clouds containing
absorbing aerosols. BB may cause ~250,000 (73,000–435,000) premature mortalities/yr, with >90% from particles. AHFs
from all sources and AMFs + AHFs from power plants and electricity use each may cause a statistically significant +0.03 K
global warming. Solar plus thermal-IR DRFs were +0.033 (+0.027) W/m2 for all AHFs globally without (with) evaporating
cooling water, +0.009 W/m2 for AMFs globally, +0.52 W/m2 (94.3% solar) for all-source BC outside of clouds plus
interstitially between cloud drops at the cloud relative humidity, and +0.06 W/m2 (99.7% solar) for BC inclusions in cloud
hydrometeor particles. Modeled post-1850 biomass, biofuel, and fossil fuel burning, AHFs, AMFs, and urban surfaces
accounted for most observed global warming.
Jacobson, M. J. (2014) Effects of biomass burning on climate, accounting for heat and moisture fluxes, black and brown carbon, and cloud
absorption effects, JOURNAL OF GEOPHYSICAL RESEARCH: ATMOSPHERES.
Click Here to Return to the Table of Contents
WASTE
Global Emissions of Trace Gases, Particulate Matter, and Hazardous Air Pollutants from Open Burning of
Domestic Waste
Abstract - The open burning of waste, whether at individual residences, businesses, or dump sites, is a large source of air
pollutants. These emissions, however, are not included in many current emission inventories used for chemistry and climate
modeling applications. This paper presents the first comprehensive and consistent estimates of the global emissions of
greenhouse gases, particulate matter, reactive trace gases, and toxic compounds from open waste burning. Global emissions
of CO2 from open waste burning are relatively small compared to total anthropogenic CO2; however, regional CO2
emissions, particularly in many developing countries in Asia and Africa, are substantial. Further, emissions of reactive trace
gases and particulate matter from open waste burning are more significant on regional scales. For example, the emissions of
PM10 from open domestic waste burning in China is equivalent to 22% of China’s total reported anthropogenic PM10
emissions. The results of the emissions model presented here suggest that emissions of many air pollutants are significantly
underestimated in current inventories because open waste burning is not included, consistent with studies that compare
model results with available observations.
23
Wiedinmyer, C., R. J. Yokelson, & B. K. Gullett (2014) Global Emissions of Trace Gases, Particulate Matter, and Hazardous Air
Pollutants from Open Burning of Domestic Waste, ENVIRONMENTAL SCIENCE & TECHNOLOGY.
Click Here to Return to the Table of Contents
TRANSPORT & INDUSTRY
Analysis of greenhouse gas emissions of freight transport sector in China
Abstract - Due to the increasing commercial activities in China, the rapid growth of energy consumption and greenhouse
gas (GHG) emissions in the freight transport sector has alarmed the Chinese central government. However, there is a lack of
standard measure for evaluating GHG emissions generated from freight transport operations. To improve this situation,
Chinese policy makers need to evaluate GHG emissions for energy saving and pollution reduction. This background leads us
to examine the GHG emission trajectories and features of Chinese freight transport patterns in the last decade, i.e. between
2000 and 2011. In this study, we examine different regions’ freight turnover and energy consumption by various transport
modes (i.e. railway, highway, waterway, aircraft, and oil pipeline) in China. Our results show that the total amount of GHG
emissions caused by the Chinese freight transport sector reached 978 million tons in 2011, indicating an average annual
growth of 74 million tons CO2e for the last decade. Shandong, Anhui, and Henan are the main provinces producing GHG
emissions, representing 11.7%, 10.3%, and 10% of total emissions generated from the freight transport sector in China,
respectively. This study also compares the regional GHG emissions from different freight transport modes including railway,
highway, waterway, air transport, and oil pipeline. Based on the findings, policy implications are provided on how to mitigate
freight transport emissions among different Chinese regions.
Tian Y., Q. Zhu, K. Lai, & Y.H. V. Lun (2014) Analysis of greenhouse gas emissions of freight transport sector in China, JOURNAL OF
TRANSPORT GEOGRAPHY (in press).
Click Here to Return to the Table of Contents
FOSSIL FUELS
Global Bottom-Up Fossil Fuel Fugitive Methane and Ethane Emissions Inventory for Atmospheric
Modeling
Abstract - Natural gas (NG)-related fugitive methane (CH4) emissions estimates from life cycle assessments (LCA) and local
field measurements are highly uncertain. Globally distributed long-term atmospheric measurements and top-down modeling
can help understand whether LCA and field studies are representative of the global industry average. Attributing sources,
such as the NG industry, to global total top-down emissions estimates requires detailed and transparent global a priori
bottom-up emissions inventories. Establishing an a priori bottom-up inventory as a tool for top-down modeling is the focus
of this work, which extends existing fossil fuel (FF) inventories over the past three decades: (i) It includes ethane (C2H6)
emissions, which is a convenient FF tracer gas given available global C2H6 observations. (ii) Fuel specific CH4 and C2H6
emissions uncertainties are quantified. (iii) NG CH4 and C2H6 emissions are estimated for different fugitive emissions rate
(FER; % of dry production) scenarios as a basis for quantifying global average FER top-down. While our global oil and coal
CH4 estimates coincide well with DGAR v4.2 for most years, country-level emissions vary substantially, and coal emissions
increase at a lower rate over the past decade. Global emissions grid maps are presented for use in top-down modeling
Schwietzke, S., W. M. Griffin, H. S. Matthews, & L. M. P. Bruhwile (2014) Global Bottom-Up Fossil Fuel Fugitive Methane and
Ethane Emissions Inventory for Atmospheric Modeling, ACS SUSTAINABLE CHEMISTRY & ENGINEERING.
Assessment and risk analysis of casing and cement impairment in oil and gas wells in Pennsylvania, 2000–
2012
Abstract - Casing and cement impairment in oil and gas wells can lead to methane migration into the atmosphere and/or
into underground sources of drinking water. An analysis of 75,505 compliance reports for 41,381 conventional and
24
unconventional oil and gas wells in Pennsylvania drilled from January 1, 2000–December 31, 2012, was performed with the
objective of determining complete and accurate statistics of casing and cement impairment. Statewide data show a sixfold
higher incidence of cement and/or casing issues for shale gas wells relative to conventional wells. The Cox proportional
hazards model was used to estimate risk of impairment based on existing data. The model identified both temporal and
geographic differences in risk. For post-2009 drilled wells, risk of a cement/casing impairment is 1.57-fold [95% confidence
interval (CI) (1.45, 1.67); P < 0.0001] higher in an unconventional gas well relative to a conventional well drilled within the
same time period. Temporal differences between well types were also observed and may reflect more thorough inspections
and greater emphasis on finding well leaks, more detailed note taking in the available inspection reports, or real changes in
rates of structural integrity loss due to rushed development or other unknown factors. Unconventional gas wells in
northeastern (NE) Pennsylvania are at a 2.7-fold higher risk relative to the conventional wells in the same area. The predicted
cumulative risk for all wells (unconventional and conventional) in the NE region is 8.5-fold [95% CI (7.16, 10.18); P <
0.0001] greater than that of wells drilled in the rest of the state.
Ingraffea, A. R., M. T. Wells, R. L. Santoro, & S. B. C. Shonkoff (2014) Assessment and risk analysis of casing and cement
impairment in oil and gas wells in Pennsylvania, 2000–2012, PNAS (Early View).
Natural Gas Fugitive Emissions Rates Constrained by Global Atmospheric Methane and Ethane
Abstract - The amount of methane emissions released by the natural gas (NG) industry is a critical and uncertain value for
various industry and policy decisions, such as for determining the climate implications of using NG over coal. Previous
studies have estimated fugitive emissions rates (FER)—the fraction of produced NG (mainly methane and ethane) escaped
to the atmosphere—between 1 and 9%. Most of these studies rely on few and outdated measurements, and some may
represent only temporal/regional NG industry snapshots. This study estimates NG industry representative FER using global
atmospheric methane and ethane measurements over three decades, and literature ranges of (i) tracer gas atmospheric
lifetimes, (ii) non-NG source estimates, and (iii) fossil fuel fugitive gas hydrocarbon compositions. The modeling suggests an
upper bound global average FER of 5% during 2006–2011, and a most likely FER of 2–4% since 2000, trending downward.
These results do not account for highly uncertain natural hydrocarbon seepage, which could lower the FER. Further
emissions reductions by the NG industry may be needed to ensure climate benefits over coal during the next few decades.
Schwietzke, S., W. M. Griffin, H. S. Matthews, & L. M. P. Bruhwiler (2014) Natural Gas Fugitive Emissions Rates
Constrained by Global Atmospheric Methane and Ethane, ENVIRON. SCI. TECHNOL. 48(14):7714–7722.
Methane Destruction Efficiency of Natural Gas Flares Associated with Shale Formation Wells
Abstract - Flaring to dispose of natural gas has increased in the United States and is typically assumed to be 98% efficient,
accounting for both incomplete combustion and venting during unintentional flame termination. However, no in situ
measurements of flare emissions have been reported. We used an aircraft platform to sample 10 flares in North Dakota and
1 flare in Pennsylvania, measuring CO2, CH4, and meteorological data. Destruction removal efficiency (DRE) was calculated
by assuming a flare natural gas input composition of 60−100% CH4. In all cases flares were >99.80 efficient at the 25%
quartile. Crosswinds up to 15 m/s were observed, but did not significantly adversely affect efficiency. During analysis
unidentified peaks of CH4, most likely from unknown venting practices, appeared much larger in magnitude than emissions
from flaring practices. Our analysis suggests 98% efficiency for nonsputtering flares is a conservative estimate for incomplete
combustion and that the unidentified venting is a greater contributor to CH4 emissions.
Caulton, D. R., P. B. Shepson, M. O. L. Cambaliza, D. McCabe, E. Baum, & B. H. Stirm (2014) Methane Destruction Efficiency
of Natural Gas Flares Associated with Shale Formation Wells, ENVIRONMENTAL SCIENCE & TECHNOLOGY.
Click Here to Return to the Table of Contents
CROSS CUTTING & EMERGING SLCP SOURCE SECTORS
Pediatric burns in military hospitals of China from 2001 to 2007: A retrospective study
Abstract – Background - Childhood burns are a global health problem. To date, no epidemiological study with a large
sample size of hospitalized pediatric burn patients from the Chinese mainland has been conducted. This study retrospectively
analyzed pediatric burn cases to identify the characteristics of pediatric burns and their risk factors in China. Methods - Data
25
for pediatric burn inpatients younger than 14 years were retrieved from the Chinese Trauma Databank (CTDB). The
epidemiological characteristics of pediatric burns and risk factors for mortality were analyzed. Results - A total of 61,068
cases were included in the study. Children under 3 years old were at the highest risk of injury. Scalds were the commonest
burns (87.59%). Flame burns occurred more in winter, and electrical burns occurred mainly in July and August. Age,
etiology, depth of injury, total body surface area (TBSA), site of injury, and outcome were correlated with length of hospital
stay. Risk factors for pediatric burn mortality included being male, having third degree burns, ≥30% TBSA, and having
multi-site burns. Conclusion - The results showed the epidemiological characteristics of pediatric burns in China, which
differ from those reported for other countries and regions. These characteristics can be used to develop measures to prevent
pediatric burns.
Xu J.-H., J. Qiu, J.-H. Zhou, L. Zhang, D.-F. Yuan, W. Dai, & Z.-M. Gao (2014) Pediatric burns in military hospitals of China from
2001 to 2007: A retrospective study, BURNS (in press).
Global Methane Emissions from Pit Latrines
Abstract - Pit latrines are an important form of decentralized wastewater management, providing hygienic and low-cost
sanitation for approximately one-quarter of the global population. Latrines are also major sources of the greenhouse gas
methane (CH4) from the anaerobic decomposition of organic matter in pits. In this study, we develop a spatially explicit
approach to account for local hydrological control over the anaerobic condition of latrines and use this analysis to derive a
set of country-specific emissions factors and to estimate global pit latrine CH4 emissions. Between 2000 and 2015 we project
global emissions to fall from 5.2 to 3.8 Tg y−1, or from ∼2% to ∼1% of global anthropogenic CH4 emissions, due largely to
urbanization in China. Two and a half billion people still lack improved sanitation services, however, and progress toward
universal access to improved sanitation will likely drive future growth in pit latrine emissions. We discuss modeling results in
the context of sustainable water, sanitation, and hygiene development and consider appropriate technologies to ensure
hygienic sanitation while limiting CH4 emissions. We show that low-CH4 on-site alternatives like composting toilets may be
price competitive with other CH4 mitigation measures in organic waste sectors, with marginal abatement costs ranging from
57 to 944 $/ton carbon dioxide equivalents (CO2e) in Africa and 46 to 97 $/ton CO2e in Asia.
Reid, M. C., K. Guan, F. Wagner, & D. L. Mauzerall (2014) Global Methane Emissions from Pit Latrines, ENVIRONMENTAL
SCIENCE & TECHNOLOGY.
26