David Cocker
Department of Chemical and
Environmental Engineering
CE-CERT

• Development of a detailed chemical mechanism for the prediction of ozone, toxics, and secondary organic aerosol(SOA) formation within the atmosphere
– Studies of ozone and SOA at VOC and NO x similar to the urban atmosphere levels
– Investigation of gas-particle partitioning of semivolatile compounds in the presence of ambient particle loadings
– Improved interpretation of ambient data obtained using aerosol mass spectrometers

• Created by a chemical reaction between volatile organic compounds (VOCs) and oxides of nitrogen (NO x
) in the presence of sunlight.
VOC + NO x
+ sunlight

Ozone
• Lung irritant
• Permanent lung damage
• Asthmatic trigger asthma
• Reduced lung function
• Increased respiratory illnesses.
• Plant and ecosystem damage.

U.S. Counties in non-attainment for Phase II Ozone Rule, 2005
(0.08 ppm for 8 hr standard) www.epa.gov

• Microscopic liquids and/or solids sufficiently small to deeply penetrate the lungs.
• Study Motivated by Clean Air Rules, 2004
– Health-based Standards
• Linked to premature death
• Aggravation of cardiovascular and respiratory disease
• Decreased lung function
• Asthmatic triggers
• Coughing/wheezing/difficulty breathing
• Many counties in most populous regions within the
United States designated as non-attainment areas

U.S. Counties in non-attainment for fine particle standard, 2005
(65
µ g m -3 for 8 hr standard) www.epa.gov

• Secondary aerosol can contribute to the majority of fine particulate mass concentrations in polluted regions
• SOA significant contributor to fine particle concentrations in urban airsheds
– Up to 80% of urban organic carbon attributed to secondary organic aerosol

Sources of PM
2.5
in Western Riverside County
R 2 = 0.91
χ 2 = 0.53
% MB = 115.9

Q. Zhang, et al.GRL, 34:L13801, 2007

• Visibility reduction:
Pasadena, CA

• Global radiative forcing (direct and indirect) thereby affect global climate change

How does Aerosol Affect us?
Health Effect
Regional
Air Quality
Climate
Effect

Impacts of PM
2.5
Pollution in South Coast Basin
“ Exposures to air pollution can shorten life by about 14 years for people who die prematurely”
— CARB 2007
Source: California Air Resources Board, 2007; 1999-2000 Air Quality Data

Scenario
Emissions
Control
Conditions Strategies
Air Quality Model
Other Model
Components
Chemical
Mechanism
Critical to predicting secondary pollutants
Air Quality
Predictions
Health and Social
Impacts

Source Characterization

International Shipping Trade Routes infranetlab.org/blog/2008/10/goodbye-global/

Ports of Los Angeles and Long Beach
• Nation’s largest container cargo port complex
•>40 % of nation’s containerized imports arrive here

• Main Propulsion Engine
– Two Stroke
– Displacement > 1000 liters/Cyl
(6-12 cyl)
– 54,000 kW, 90 rpm Main Engine Cylinder
• Auxiliary Engine
– Four Stroke
– Displacement > 10 liters/Cyl
(6cyl)
– 900 kW, 900 rpm

• Heavy Fuel Oil (HFO)
– Commonly known as bunker fuel or residual oil
– Residual fraction from crude refining
– Used on main engine and boiler
– Very high viscosity and high sulfur content (2.6% m/m)
• Marine Gas Oil and Marine Distillate Oil
– Refined fraction from crude distillation
– Used on auxiliary engine
– Lower sulfur content (0.16 %m/m)
21

23

Photograph taken of the container ship from the cabin of the CIRPAS Twin
Otter

Particle Size
• Soot (D primary
~30nm)
• Nanoparticles(5-8nm)
• Unknown particles( 30-80nm)
• EDS found V and S both from nanoparticles and unknown particles.

Comparison of PM Emissions (g/kg
CO
2
)
3
2.5
1
0.75
0.5
0.25
0
HDD trucks Switching
Locomotives
Ship Main
Engine
Ship Auxiliary
Engine
Yard Tractor BUG Aircraft

Total Hydrocarbon Emissions (g/kg
CO
2
)
3
1.25
1
0.75
`
0.5
0.25
0
HDD trucks Switching
Locomotives
Ship Main
Engine
Ship Auxiliary
Engine
Yard Tractor BUG Aircraft

Comparison of PM Emissions
(g/mile/ton)
0.035
0.03
0.025
0.02
0.015
0.01
0.005
0
1994-97 1998
HDD Trucks
1999-
2002
SD-18 SD-20 SW-
1200St1
SW-
1200St2
Locomotive
Main
Engine
Auxiliary
Engine
Ships

Moving From Primary to Secondary
Pollutants
• Ozone: only formed in atmosphere
• Particulate matter: 80% formed in the atmosphere

Theory and
Estimations
Basic Lab.
Data
Chemical
Characterization
Instrumentation
Chemical Mechanism
Simulation of Experiments
No
Consistent?
No
Atmospheric
Simulation
Experiments
(Environmental
Chamber Data)
Yes
Mechanism Might be satisfactory for air quality modeling

Environmental Chamber Research

Secondary Organic Aerosol (SOA) Formation
Heterogeneous
Volatile Organic
Chemistry
Compound
Condensation
Oxidation
(OH,O
3
,NO
3
) Evaporation
Nucleation
Fine Particles Coarse Particles
0.01 0.3 2 10
Particle Diameter (
µ m)

SOA Theory: Equilibrium Partitioning of
HC + Oxidant
Semi-Volatile Compounds
α i
P i
P i
= A i
+ G i
K om,i G
1
, G
2
,…,G n
A
1
, A
2
,…,A i
A i
– Aerosol Products
G i
– Gaseous Products
M o
– Mass of Organic in Aerosol
K om
– Gas Partitioning Coefficient
A i
/
∆
M o
R – Ideal Gas Constant
K om,i
=
γ
– Activity Coefficient G i p o
Li
– Sub cooled saturation liquid vapor pressure
α
– Mass based stoichiometric coefficient
Y
=
M o
ΔHC
= ∑ i
Y i
=
M o
∑ i
1
+
α i
K om, i
K om, i
M o
(Odum et al., 1996)
=
RT
MW om
γ i p o
L,i
=
M o
α
1
+
K
K om om
M o
Single Product Model

Air handler circulation system
Purified air flushed 450 m 3 enclosure
Descending frames to maintain positive pressure
Argon arc lamp
Dual 90 m 3
Teflon reactors
Particle free two chamber humidifier
Black lights
Dual SMPS’s
Injection and sample ports
TDMA – Hygroscopicity Measurement

60
50
40
30
20
PM Volume(corrected)
PM Volume(uncorrected)
Hydrocarbon
10
0
0 100
Y
=
ΔM o
ΔROG
=
200
∑ i
Y i
500 600 300 400
Time (minute)
=
M o
∑ i
1
+
α i
K om, i
K om, i
M o
0
2
12
10
8
6
4

SOA Formation Potential (yield) as Function of Aerosol Mass (m-Xylene)
0.20
0.18
Traditional Smog
Chamber Experiments
0.12
0.10
0.08
0.06
0.04
0.02
0.00
0 50 100
M o
(
150
µ g/m
3
)
200
HCo:Nox>8.0
HCo:NOx<5.5
250 300

400
350
300
250
25
20
15
10
5
α
1
α
2
=0.049, Κ
1
=0.178, Κ
2
=0.301
=0.008
Semi-
Empirical
Model
Estimates
0
0
200
150
100
100 200
ΔHC( µ g/m
3
)
Low
NO x
300
α
1
α
2
=0.024, Κ
1
=0.152, Κ
2
=0.229
=0.004
High
NO x
50
HCo:NOx>8.0
HCo:NOx<5.5
0
0 200 400 600 800 1000
ΔHC( µ g/m
3
)
1200 1400 1600 1800 2000
Detailed chemical speciation needed to identify key oxidation products; chemical mechanism based model needed to predict impacts of NOx and other atmospheric species on SOA formation

• There are many individual and team projects that lead to the results shown above
– What do the particles formed look like?
• What are their chemical characteristics?
• What are their physical characteristics?
• What is their atmospheric behaviour?
– What hazardous air pollutants are released?
• By whom? Where? Who is impacted?
– Lots of instruments, lots of students to work with, lots of questions to address……

AMS
VOCs
+
Oxidants
CRDS
IR-CRDS
Intermediates
Products
(aerosol)
Products
(gases)
LCMS
PTR-MS
GC-FID

Atmospheric reactor
SOA
SMPS
(Size
Distribution)
(CCN)
Cloud particle activation
CPC
(Number
Concentration)
Aerosol
Mass
Produced
APM
(Single
Particle Mass)