Human Impact on the
Atmosphere
Chapters 18 and 19
Living in the Environment, 11th Edition, Miller
Advanced Placement Environmental Science
La Canada High School
Dr. E
Pollution
Thorpe, Gary S., M.S., (2002). Barron’s How to prepare for the AP Environmental Science Advanced Placement Exam
• The term “Smog” (smoke and fog) was first
used in 1905 to describe sulfur dioxide
emission
• In 1952, severe pollution took the lives of
5000 people in London
• “It isn’t pollution that’s harming the
environment. It’s the impurities in our air and
water that are doing it.”
Former U.S. Vice President Dan Quayle
www.aqmd.gov/pubinfo/ 97annual.html
Congress found:
• Most people now live in urban areas
The
Clean
Air
Act
• Growth results in air pollution
• Air pollution endangers living things
It decided:
• Prevention and control at the source was
appropriate
• Such efforts are the responsibility of
states and local authorities
• Federal funds and leadership are
essential for the development of effective
programs
Clean Air Act
• Originally signed 1963
– States controlled standards
• 1970 – Uniform Standards by Federal
Govt.
– Criteria Pollutants
• Primary – Human health risk
• Secondary – Protect materials, crops,
climate, visibility, personal comfort
Clean Air Act
• 1990 version
– Acid rain, urban smog, toxic air pollutants, ozone
depletion, marketing pollution rights, VOC’s
• 1997 version
–
–
–
–
Reduced ambient ozone levels
Cost $15 billion/year -> save 15,000 lives
Reduce bronchitis cases by 60,000 per year
Reduce hospital respiratory admission 9000/year
Clean Air Act
President George W. Bush signed rules
amending Clean Air Act that allowed power
plants and other industries to increase
pollution significantly without adopting
control measures
http://www.cnn.com/2003/LAW/12/24/bush.clean.air.ap/index.html
Appeals court blocks
Bush clean air changes
Wednesday, December 24, 2003 Posted: 2:10 PM EST (1910 GMT)
WASHINGTON (AP) -- A
federal appeals court on
Wednesday blocked new
Bush administration
changes to the Clean Air
Act from going into effect
the next day, in a
challenge from state
attorneys general and
cities that argued they
would harm the
environment and public
health.
Clean Air Act
http://www.epa.gov/air/oaq_caa.html
• Title I - Air Pollution Prevention and Control
–
–
–
–
Part A - Air Quality and Emission Limitations
Part B - Ozone Protection (replaced by Title VI)
Part C - Prevention of Significant Deterioration of Air Quality
Part D - Plan Requirements for Nonattainment Areas
• Title II - Emission Standards for Moving Sources
– Part A - Motor Vehicle Emission and Fuel Standards
– Part B - Aircraft Emission Standards
– Part C - Clean Fuel Vehicles
•
•
•
•
Title III - General
Title IV - Acid Deposition Control
Title V - Permits
Title VI - Stratospheric Ozone Protection
Outdoor Air Pollution
Primary Pollutants
CO CO2
SO2 NO NO2
Secondary Pollutants
SO3
Most hydrocarbons
Most suspended
particles
Natural
Sources
Mobile
HNO3
H 2 O2
H2SO4
O3
PANs
–
Most NO3 and SO24 – salts
Stationary
Major Sources of Primary Pollutants
Stationary Sources
• Combustion of fuels for power and heat – Power Plants
• Other burning such as Wood & crop burning or forest
fires
• Industrial/ commercial processes
• Solvents and aerosols
Mobile Sources
• Highway: cars, trucks, buses and motorcycles
• Off-highway: aircraft, boats, locomotives, farm
equipment, RVs, construction machinery, and lawn
mowers
54 million metric
tons from mobile
sources in 1990
Human Impact on Atmosphere
• Burning Fossil Fuels  Adds CO2 and O3 to
troposphere
 Global Warming
 Altering Climates
• Using Nitrogen
 Produces Acid Rain
fertilizers and
burning fossil fuels  Releases NO, NO2, N2O, and
NH3 into troposphere
• Refining petroleum  Produces acid rain
and burning fossil
 Releases SO2 into troposphere
fuels
• Manufacturing
 Releases toxic heavy metals (Pb,
Cd, and As) into troposphere
www.dr4.cnrs.fr/gif-2000/ air/products.html
Criteria Air Pollutants
EPA uses six "criteria pollutants" as indicators of
air quality
1.
2.
3.
4.
5.
6.
•
Nitrogen Dioxide: NO2
Ozone: ground level O3
Carbon monoxide: CO
Lead: Pb
Particulate Matter: PM10 (PM 2.5)
Sulfur Dioxide: SO2
Volatile Organic Compounds: (VOCs)
EPA established for each concentrations above
which adverse effects on health may occur
Nitrogen Dioxide (NO2)
• Properties: reddish brown gas, formed as
fuel burnt in car, strong oxidizing agent,
forms Nitric acid in air
• Effects: acid rain, lung and heart
problems, decreased visibility (yellow
haze), suppresses plant growth
• Sources: fossil fuels combustion, power
plants, forest fires, volcanoes, bacteria in
soil
• Class: Nitrogen oxides (NOx)
• EPA Standard: 0.053 ppm
Mobile Source Emissions:
Nitrogen Oxides
Ozone (O3)
• Properties: colorless, unpleasant odor,
major part of photochemical smog
• Effects: lung irritant, damages plants,
rubber, fabric, eyes, 0.1 ppm can lower
PSN by 50%,
• Sources: Created by sunlight acting on
NOx and VOC , photocopiers, cars,
industry, gas vapors, chemical solvents,
incomplete fuel combustion products
• Class: photochemical oxidants
Ozone (O3)
• 10,000 to 15,000 people in US admitted to
hospitals each year due to ozone-related
illness
• Children more susceptible
– Airways narrower
– More time spent outdoors
Mobile Source Emissions:
Hydrocarbons –
Precursors to Ozone
Carbon Monoxide (CO)
• Properties: colorless, odorless, heavier than
air, 0.0036% of atmosphere
• Effects: binds tighter to Hb than O2, mental
functions and visual acuity, even at low levels
• Sources: incomplete combustion of fossil fuels
60 - 95% from auto exhaust
• Class: carbon oxides (CO2, CO)
• EPA Standard: 9 ppm
• 5.5 billion tons enter atmosphere/year
Mobile Source
Emissions - CO
Lead (Pb)
• Properties: grayish metal
• Effects: accumulates in tissue; affects
kidneys, liver and nervous system
(children most susceptible); mental
retardation; possible carcinogen; 20% of
inner city kids have [high]
• Sources: particulates, smelters, batteries
• Class: toxic or heavy metals
• EPA Standard: 1.5 ug/m3
• 2 million tons enter atmosphere/year
Suspended Particulate Matter (PM10)
•Properties: particles suspended in air (<10
um)
•Effects: lung damage, mutagenic,
carcinogenic, teratogenic
•Sources: burning coal or diesel,
volcanoes, factories, unpaved roads,
plowing, lint, pollen, spores, burning
fields
•Class: SPM: dust, soot, asbestos, lead,
PCBs, dioxins, pesticides
•EPA Standard: 50 ug/m3 (annual mean)
Mobile Source Emissions: Fine
Particulate Matter (PM2.5)
Sulfur Dioxide (SO2)
• Properties: colorless gas with irritating odor
• Effects: produces acid rain (H2SO4),
breathing difficulties, eutrophication due to
sulfate formation, lichen and moss are
indicators
• Sources: burning high sulfur coal or oil,
smelting or metals, paper manufacture
• Class: sulfur oxides
• EPA Standard: 0.3 ppm (annual mean)
• Combines with water and NH4 to increase
soil fertility
VOCs (Volatile Organic Compounds)
• Properties: organic compounds (hydrocarbons) that
evaporate easily, usually aromatic
• Effects: eye and respiratory irritants; carcinogenic;
liver, CNS, or kidney damage; damages plants; lowered
visibility due to brown haze; global warming
• Sources: vehicles (largest source), evaporation of
solvents or fossil fuels, aerosols, paint thinners, dry
cleaning
• Class: HAPs (Hazardous Air Pollutants)
– Methane
– Benzene
– Chlorofluorocarbons (CFCs), etc.
• Concentrations indoors up to 1000x outdoors
• 600 million tons of CFCs
•
•
•
•
•
•
•
•
•
Other Air Pollutants
Carbon dioxide
ChloroFluoroCarbons
Formaldehyde
Benzene
Asbestos
Manganese
Dioxins
Cadmium
Others not yet fully characterized
Formation & Intensity
Factors
• Local climate (inversions, air pressure, temperature,
humidity)
• Topography (hills and mountains)
• Population density
• Amount of industry
• Fuels used by population and industry for heating,
manufacturing, transportation, power
• Weather: rain, snow,wind
• Buildings (slow wind speed)
• Mass transit used
• Economics
Thermal Inversion
cool air
Pollutants
cool air
warm air (inversion layer)
warm
air
• surface heated by sun
• warm air rises (incl. pollutants)
• cools off, mixes with air of equal
density & disperses
• surface cools rapidly (night)
• a layer of warm air overlays surface
• polluted surface air rises but cannot
disperse  remains trapped
Smog Forms
...when polluted air is stagnant
(weather conditions, geographic location)
Los Angeles, CA
Primary Pollutants
CO CO2
SO2 NO NO2
Most hydrocarbons
Most suspended
particles
Natural
Sources
Mobile
Secondary Pollutants
SO3
HNO3
H 2 O2
H2SO4
O3
PANs
–
Most NO3 and SO24 – salts
Stationary
Photochemical Smog
UV radiation
Primary Pollutants
Secondary Pollutants
NO2 + Hydrocarbons
H2O + O2
Auto Emissions
HNO3
nitric acid
O3
ozone
Photochemical Smog
Solar
radiation
Photochemical Smog
Ultraviolet radiation
NO
Nitric oxide
NO2
Nitrogen
dioxide
H2O
Water
O
Atomic
oxygen
O2
Molecular
oxygen
Hydrocarbons
PANs
Peroxyacyl
nitrates
HNO3
Nitric acid
Aldehydes
(e.g., formaldehyde)
O3
Ozone
Photochemical Smog
Indoor Air Pollution
Why is indoor air quality
important?
• 70 to 90% of time spent indoors, mostly at home
• Many significant pollution sources in the home (e.g.
gas cookers, paints and glues)
• Personal exposure to many common pollutants is
driven by indoor exposure
• Especially important for susceptible groups – e.g. the
sick, old and very young
Exposure
• Time spent in various environments in US
and less-developed countries
House of Commons Select Committee
Enquiry on Indoor Air Pollution (1991)
• “[There is] evidence that 3 million people have asthma in
the UK… and this is increasing by 5% per annum.”
• “Overall there appears to be a worryingly large number
of health problems which could be connected with indoor
pollution and which affect very large numbers of the
population.”
• [The Committee recommends that the Government]
“develop guidelines and codes of practice for indoor air
quality in buildings which specifically identify exposure
limits for an extended list of pollutants…”
Sources of Indoor Air Pollutants
•
•
•
•
•
•
•
•
•
•
•
•
Building materials
Furniture
Furnishings and fabrics
Glues
Cleaning products
Other consumer products
Combustion appliances (cookers and heaters)
Open fires
Tobacco smoking
Cooking
House dust mites, bacteria and moulds
Outdoor air
Important Indoor Air pollutants
•
•
•
•
•
•
•
•
•
•
Nitrogen dioxide
Carbon monoxide
Formaldehyde
Volatile Organic Compounds (VOCs)
House dust mites (and other allergens, e.g. from pets)
Environmental tobacco smoke
Fine particles
Chlorinated organic compounds (e.g. pesticides)
Asbestos and man-made mineral fibres
Radon
Health Effects
Nitrogen dioxide
• Respiratory irritant
• Elevated risk of respiratory illness in children,
perhaps resulting from increased susceptibility to
respiratory infection; inconsistent evidence for
effects in adults
• Concentrations in kitchens can readily exceed WHO
and EPA standards
Health Effects
Carbon monoxide
• An asphyxiant and toxicant
• Hazard of acute intoxication, mostly from
malfunctioning fuel-burning appliances and
inadequate or blocked flues
• Possibility of chronic effects of long-term
exposure to non- lethal concentrations,
particularly amongst susceptible groups
Health Effects
Formaldehyde
• Sensory and respiratory irritant and sensitizer
• Possible increased risk of asthma and chronic
bronchitis in children at higher exposure levels
• Individual differences in sensory and other
transient responses
• Caution over rising indoor concentrations
Health Effects
Volatile Organic Compounds (VOCs)
• Occur in complex and variable mixtures
• Main health effects relate to comfort and wellbeing, but benzene (and other VOCs) are
carcinogenic
• Concern about possible role of VOCs in the
aetiology of multiple chemical sensitivity; also
implicated in sick building syndrome
Health Effects
House dust mites
• House dust mites produce Der p1 allergen, a potent
sensitizer
• Good evidence of increased risk of sensitization with
increasing allergen exposure, but this does not
necessarily lead to asthma
• Small reductions in exposure will not necessarily lead to
reduced incidence and/or symptoms
• Indoor humidity is important
Health Effects
Fungi and bacteria
• Dampness and mould-growth linked to selfreported respiratory conditions, but little
convincing evidence for association between
measured airborne fungi and respiratory
disease
• Insufficient data to relate exposure to (nonpathogenic) bacteria to health effects in the
indoor environment
Health Effects
Environmental tobacco smoke (ETS)
•
•
•
•
Sudden infant death syndrome
Lower respiratory tract illness
Middle ear disease
Asthma
12 million children exposed to secondhand
smoke in homes
Health Effects
Fine particles
• Consistent evidence that exposure to small
airborne particles (e.g. PM10) in ambient air
can impact on human health; mechanisms
uncertain
• Chronic Obstructive Pulmonary Disease and
Cardiovascular Disease patients and
asthmatics probably at extra risk
• Relative importance of indoor sources is
unknown
Health Effects
Radon
• Can cause lung cancer
• Estimated that 7,000 to 30,000 Americans die
each year from radon-induced lung cancer
• Only smoking causes more lung cancer deaths
• Smokers more at risk than non-smokers
Radon Risk: Non-Smoker
Radon Level If 1000 people who did not smoke were This risk of cancer from
exposed to this level over a lifetime.. radon exposure compares
(pCI/L)
What to do:
About X would get lung cancer
to …
20
8
Being killed in a violent
Fix your home
crime
10
4
Fix your home
8
3
4
2
2
<1
1.3
<1
.4
<1
10x risk of dying in a
plane crash
Risk of drowning
Fix your home
Risk of dying in a home
fire
Average indoor radon
level
Average indoor radon
level
Fix your home
Fix your home
Fix your home
Fix your home
If you are a former smoker, your risk may be higher
Radon Risk: Smoker
Radon Level
(pCI/L)
20
If 1000 people who smoke were
exposed to this level over a lifetime..
About X would get lung cancer
135
10
71
8
57
4
29
2
15
1.3
9
.4
3
This risk of cancer from
What to do:
radon exposure compares Stop smoking and
to …
…
100x risk of drowning
Fix your home
100x risk of dying in a
home fire
Fix your home
Fix your home
100x risk of dying in a
plane crash
2x the risk of dying in a
car crash
Average indoor radon
level
Average indoor radon
level
Fix your home
Fix your home
Fix your home
Fix your home
If you are a former smoker, your risk may be lower
Radon
• 55% of our exposure to radiation comes
from radon
• colorless, tasteless, odorless gas
• formed from the decay of uranium
• found in nearly all soils
• levels vary
(From: http://www.epa.gov/iaq/radon/zonemap.html)
Zone pCi/L
1
2
3
>4
2-4
<2
Radon: How it Enters Buildings
•
•
•
•
•
•
•
Cracks in solid floors
Construction joints
Cracks in walls
Gaps in suspended floors
Gaps around service pipes
Cavities inside walls
The water supply
http://www.epa.gov/iaq/radon/pubs/citguide.html#howdoes
Radon: Reducing the Risks
• Sealing cracks in floors and walls
• Simple systems using pipes and fans
• More information:
http://www.epa.gov/iaq/radon/pubs/consguid.html#reductionte
ch
Sick Building Syndrome (SBS)
vs
Building Related Illness (BRI)
Sick Building Syndrome
• A persistent set of symptoms in > 20%
population
• Causes(s) not known or recognizable
• Complaints/Symptoms relieved after exiting
building
Complaints/Symptoms
•
•
•
•
•
Headaches
Fatigue
Reduced Mentation
Irritability
Eye, nose or throat
irritation
•
•
•
•
•
Dry Skin
Nasal Congestion
Difficulty Breathing
Nose Bleeds
Nausea
Building Related Illness
• Clinically Recognized Disease
• Exposure to indoor air pollutants
• Recognizable Causes
Clinically Recognized Diseases
–Pontiac Fever – Legionella spp.
–Legionnaire's Disease
–Hypersensitivity Pneumonitis
–Humidifier Fever
–Asthma
–Allergy
–Respiratory Disease
• Chronic Obstructive Pulmonary Disease
Ventilation
Movement of Air Into / Out of Homes
• Amount of air available to dilute pollutants
– important indicator of the likely contaminant
concentration
• Indoor air can mix with outside air by
three mechanisms
– infiltration
– natural ventilation
– forced ventilation
Movement of Air Into / Out of Homes
• Infiltration
– natural air exchange that occurs between a building
and its environment when the doors and windows are
closed
– leakage through holes or openings in the building
envelope
– pressure induced
• due to pressure differentials inside and outside of the
building
• especially important with cracks and other openings in
wall
Movement of Air Into / Out of Homes
• Infiltration
– Temperature induced (stack effect)
• driven by air movement through holes in floors,
ceilings
• in winter, warm air in a building wants to rise, exits
through cracks in ceiling and draws in
Movement of Air Into / Out of Homes
• Natural ventilation
– air exchange that occurs when windows or doors are
opened to increase air circulation
• Forced ventilation
– mechanical air handling systems used to induce air
exchange using fans and blowers
• Trade-offs
– cut infiltration to decrease heating and cooling costs vs.
indoor air quality problems
Movement of Air Into / Out of Homes
• Infiltration rates
– Influenced by
• how fast wind is blowing, pressure differentials
• temperature differential between inside and
outside of house
• location of leaks in building envelope
Greenhouse Effect
http://royal.okanagan.bc.ca/mpidwirn/atmosphereandclimate/cascade.html
Natural Greenhouse Effect
• With Greenhouse Effect average
global temperature 60 degrees
• Without it, Earth would be a
frigid planet, with average
temperature around zero degrees
Fahrenheit
Global Warming
Increased Greenhouse Gases in the Troposphere
CO2 CFCs CH4
Excess heat
Greenhouse Gases
Carbon dioxide
Methane
Nitrous oxide
Ozone
CFC’s
Hydrofluorocarbons
Perfluorinated carbons
Water vapour
Average Surface Temperature (°C)
Average Temperature Over Past 900,000 Years
17
16
15
14
13
12
11
10
9
900
800
700
600
500
400
300
Thousands of Years Ago
200
100
Present
Temperature Change Over Past 22,000 Years
2
Temperature Change (°C)
Agriculture established
1
0
-1
-2
End of
last ice
age
-3
Average temperature over past
10,000 years = 15°C (59°F)
-4
-5
20,000
10,000
2,000
1,000
Years Ago
200
100
Now
Average Surface Temperature (°C)
Average Temperature Over Past 130 Years
15.0
14.8
14.6
14.4
14.2
14.0
13.8
13.6
1860
1880
1900
1920
1940
Year
1960
1980
2000
2020
Is this increase in
temperature natural
or ?
360
340
320
300
280
Carbon dioxide
260
240
220
+2.5
200
0
180
–2.5
–5.0
Temperature
change
160
120
80
–7.5
–10.0
End of
last ice age
40
0
Thousands of Years Before Present
Variation of temperature (˚C)
from current level
Concentration of CO2
in the Atmosphere (ppm)
380
Carbon dioxide
Methane
Nitrous oxide
Index (1900 = 100)
250
200
150
100
1990
2000
2025
Year
2050
2075
2100
Measurements made at
Mauna Loa, Hawaii;
elevation = 12,000 feet
Contribution to
Greenhouse
Effect
Methane
• Core samples taken from old ocean sediment
layers have been used to trace back in time
the climate changes that have occurred over
the past tens of millions of years
• short periods of only a few hundred years in
the geological past when rapid increases of
the Earth's temperature have occurred
superimposed on top of the rise and fall of
average temperatures over the longer term
up to 15 degrees centigrade warmer than
today.
Methane
• Temperatures then fell back to the long term
trend, the whole rise and fall only lasting a
few hundred years.
• The most likely cause of this rapid global
warming over such a short period is the
release of methane into the atmosphere.
• Methane is 60 times more powerful than CO2
as a greenhouse gas
• Methane was released due to breakdown of
material associated with permafrost
6.0
Change in Temperature (ºC)
5.5
Predictions of Future Warming?
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
1850
1875
1900
1925
1950
1975
Year
2000
2025
2050
2075 2100
Top Greenhouse Gas
Emitters
•
•
•
•
•
•
•
•
•
19.1 % - United States
9.9% - China
5.1% - Japan
4.3% - Brazil
3.8 % - Germany
3.7% - Japan
2.4% - United Kingdom
1.9% - Indonesia
1.7% - Italy
What impacts have
occurred? and are
predicted to occur
from global warming?
Atmosphere Impacts from Global Warming?
Weather
Ocean currents
Sea level
Water resources
Biodiversity
Forests
Human health
Agriculture
Human demographics
Agriculture
Water Resources
•
Shifts in food-growing areas
• Changes in water supply
•
Changes in crop yields
•
• Decreased water quality
Increased irrigation demands
•
Increased pests, crop
diseases, and weeds in
warmer areas
• Increased drought
• Increased flooding
Forests
•
Changes in forest composition and
locations
•
Disappearance of some forests
•
Increased fires from drying
•
Loss of wildlife habitat and species
Biodiversity
Sea Level and Coastal Areas
•
Extinction of some plant and
animal species
•
•
•
Loss of habitats
•
•
Disruption of aquatic life
•
•
•
Weather Extremes
•
Prolonged heat waves and
droughts
Rising sea levels
Flooding of low-lying islands and
coastal cities
Flooding of coastal estuaries,
wetlands, and coral reefs
Beach erosion
Disruption of coastal fisheries
Contamination of coastal aquifiers
with salt water
Human Health
Human Population
• Increased deaths
•
Increased flooding
• More environmental refugees
•
More intense hurricanes,
typhoons, tornadoes, and
violent storms
• Increased migration
•
Increased deaths from heat and
disease
•
Disruption of food and water
supplies
•
Spread of tropical diseases to
temperate areas
•
Increased respiratory disease
•
Increased water pollution from
coastal flooding
Direct manifestations
• Heat waves and periods of unusually warm
weather
• Sea level rise and coastal flooding
• Glaciers melting
• Arctic and Antarctic warming with ice shelves
breaking up
• Increase severity of weather
• Zooplankton are dying in the Pacific Ocean
Heat wave kills 30, no relief in sight
July 27, 1999
http://www.cnn.com/WEATHER/9907/27/heat.wave.02/index.html
Monster iceberg breaks off
Antarctic ice shelf
May 10, 2002
http://www.cnn.com/2002/TECH/space/05/09/iceberg.satellite/index.html
Greenland
Cold water melting from
Antarctica's ice cap and
icebergs falls to the ocean floor
and surges northward, affecting
worldwide circulation.
Antarctica
0
0
–130
250,000
–426
200,000
150,000
100,000
Years before present
50,000
0
Present
Height below present
sea level (feet)
Height above or below
present sea level (meters)
Today’s sea level
If all the ice on Greenland melted,
world sea levels would rise about six
metres (20 feet)
If all the ice on the Antarctic continent
melted, sea levels would rise over 70
metres (230 feet)
This is unlikely to happen, but small
increases will continue.
Possible Consequences
• Spreading disease
• Earlier spring arrival
• Plant and animal range shifts and
population declines
• Coral reef bleaching
• Downpours, heavy snowfalls, and flooding
• Droughts and fires
Global warming may harm
human health
November 16, 1998
Climatic changes related
to global warming could
foster dangerous outbreaks
of cholera, dengue fever
and malaria, …
http://www.cnn.com/TECH/science/9811/16/climate.health.enn/index.html
Study: Global warming spurs
migrations
Thursday, January 2, 2003
Rising global temperatures that have lured plants
into early bloom and birds to nest earlier in the
spring are altering the ranges and behavior of
hundreds of plant and animal species worldwide,
two studies conclude.
http://www.cnn.com/2003/TECH/science/01/02/climate.migrations.ap/index.html
Report: Coral bleaching hits
record level
May 19, 1999
Global warming has
been linked to an
unprecedented episode
of coral bleaching
in 1998, …
http://www.cnn.com/NATURE/9905/19/coral.bleaching.enn/index.html
Vicious cycle: Global warming feeds
fire potential
November 2, 2000
Global warming may greatly accelerate the fire
cycle in the desert ecosystem of North America,
according to a study published today in the journal
Nature.
Elevated carbon dioxide levels, the result of
increased fossil fuel burning, can alter the delicate
balance of grasses in desert areas, the report notes.
This finding may have major implications for the
biodiversity and health of desert ecosystems in the
western United States.
"This could be a real problem for land managers,"
said Stan Smith, a professor of biology at the
University of Nevada in Las Vegas and lead
author of the study. http://www.cnn.com/2000/NATURE/11/02/global.warming.enn/index.html
http://www.soton.ac.uk/~engenvir/environment/air/greenhouse.problems.html
Anomaly = difference between actual value and some
mean value; in this case the mean is a 30 year average
Warmest Years on Record
•
•
•
•
•
•
•
1981
1983
1987
1988
1989
1990
1991
•
•
•
•
•
•
•
•
1994
1995
1996
1997
1998
1999
2000
2001
Ozone Hole
Understanding Ozone
http://royal.okanagan.bc.ca/mpidwirn/atmosphereandclimate/ozonehole.html
• Discovered in 1839 by German scientist Christian Friedrich
Schonbein
• Pale blue, unstable molecule made of three oxygen atoms
• Vital to life in the stratosphere
• Harmful to plants and humans in the troposphere
• Concentration: stratosphere  up to 15 ppm at about 25
km
• Formed when atomic oxygen (O) from higher parts of the
atmosphere collides with molecular oxygen (O2) in the
stratosphere
• UV radiation splits the ozone back to O and O2 and it can
form another ozone molecule
http://www-imk.fzk.de/topoz-iii/ataglanz/ozonbild.html
http://www-imk.fzk.de/topoz-iii/ataglanz/ozonzerst.html
The Ozone Hole
• First discovered in 1985: observations from
Antarctica extend back into 1950’s.
• Characterized as a rapid depletion of ozone over
Antarctica during spring.
– Ozone hole season, Spring (August – October)
– Ozone hole located over mainly over Antarctica.
– Ozone hole recovers by late December
• Ozone hole caused by human chemicals (CFC’s)
• Ozone hole not present in early 1970’s
science.widener.edu/svb/ atmo_chem/oct15.html
Ozone hole stabilizes
October 17, 2001
WASHINGTON (CNN) --
A hole in the Earth's protective ozone layer
is about the same size as in the past three
years, according to scientists at the National
Oceanic and Atmospheric Administration,
who predict it will hold steady in the near
future.
Satellite data show the hole over Antarctica,
which allows more harmful solar radiation to
reach the Earth, peaked this year at about 10
million square miles (26 million square km),
roughly the size of North America.
http://www.cnn.com/2001/TECH/space/10/17/ozone.hole.size/index.html
History of Ozone Depletion
• CFCs developed in 40’s and 50’s
– Refrigerants, propellants, fire retardants
• 1970’s CFCs detected in atmosphere.
– Many of these have long atmospheric lifetimes (10’s
to 100’s of years)
• 1974 Rowland and Molina propose that CFC’s
can destroy ozone in the stratosphere.
– CFCs broken apart by UV radiation forming
chlorine which can destroy ozone quickly:
• O3 +Cl  ClO+ O2
• ClO+O  Cl+O2
(Catalytic Reaction)
Chlorofluorocarbons or CFCs
• First produced by General Motors
Corporation in 1928, CFCs were created as a
replacement to the toxic refrigerant
ammonia
• CFCs have also been used as a propellant in
spray cans, cleaner for electronics, sterilant
for hospital equipment, and to produce the
bubbles in Styrofoam
• CFCs are cheap to produce and very stable
compounds, lasting up to 200 years in the
atmosphere
• Many countries have recently passed laws
banning nonessential use of these chemicals.
• Nevertheless, by 1988 some 320,000 metric
tons of CFCs were used worldwide.
Action of CFCs
• CFCs created at the Earth's surface drift slowly
upward to the stratosphere where UV radiation
from the sun causes their decomposition and the
release of chlorine
• Chlorine in turn attacks the molecules of ozone
converting them into oxygen molecules
Cl + O3 »»» ClO + O2
ClO + O »»» Cl + O2
Ultraviolet light hits a chlorofluorocarbon
(CFC) molecule, such as CFCl3, breaking
off a chlorine atom and leaving
CFCl2.
Sun
Cl Cl
C
Cl
F
UV radiation
Once free, the chlorine atom is off
to attack another ozone molecule
and begin the cycle again.
Cl
Cl
O
The chlorine atom
attacks
an ozone (O3) molecule,
pulling an oxygen atom
off it and leaving
O
an oxygen
O
O
molecule (O2).
O
A free oxygen atom pulls
the oxygen atom off
the chlorine monoxide
molecule to form O2.
Cl
The chlorine
Cl
atom and the
O
oxygen atom join
to form a chlorine
O
monoxide molecule (ClO) O
Cl
O
O
http://www.clas.ufl.edu/users/dlsmith/Lecture_11.html
A single chlorine atom
removes about 100,000
ozone molecules before it
is taken out of operation
by other substances
Low and Middle Latitudes
Current measurements indicate
that the amount of ozone in the
stratosphere of the low and
middle latitudes has decreased
by about 3% with estimates
that it will decrease by10% by
2025
Harmful effects of UV
radiation.
• Skin cancer (ultraviolet radiation can destroy
acids in DNA)
• Cataracts and sun burning
• Suppression of immune systems
• Adverse impact on crops and animals
• Reduction in the growth of ocean
phytoplankton
• Cooling of the Earth's stratosphere and
possibly some surface climatic effect
• Degradation of paints and plastic material
matrix.ucdavis.edu/tumors/tradition/ gallery-ssmm.html
www.snec.com.sg/clinical_services/ cataract.asp
Conclusion
• Ozone Depletion Exists and effects certain
areas of the Earth more than others
• Currently, one in five North Americans and
one in two Australians will develop some form
of skin cancer in their lifetime
• With a sustained 10% decrease in
stratospheric ozone, an additional 300,000 nonmelanoma and 4,500 melanoma skin cancers
could be expected world-wide, according to
UNEP estimates.
Acid Deposition
Measuring Acid
Rain
• Acid rain is measured using a "pH"
scale.
– The lower a substance's pH, the more
acidic it is.
• Pure water has a pH of 7.0.
– Normal rain is slightly acidic and has
a pH of about 5.6
• Any rainfall has a pH value less than 5.6
is defined as acid rain
• As of the year 2000, the most acidic rain
falling in the US has a pH of about 4.3.
Two Forms…
• Wet
• Dry
Refers to acid
Refers to acidic
rain, fog, sleet,
gases and
cloud vapor and
particles.
snow.
Compounds
Two main contributers to acid deposition:
• Sulfur Dioxide (SO2)
• Nitrogen Oxides (NOx)
* 66% of all sulfur dioxides and 25% of
all nitrogen oxides comes from electric
power generation that produces energy
by burning fossil fuels.
When gas pollutants e.g. sulphur
dioxide, nitrogen dioxide dissolve
in rain water, various acids are
formed.
CO2 + H2O
SO2 + H2O
NO2 + H2O



H2CO3 (carbonic acid)
H2SO3 (sulphorous acid)
HNO2 (nitrous acid) +
HNO3 (nitric acid)
Causes of
Acid Rain
• Sulfur dioxide (SO2) and nitrogen
oxides (NOx) are the primary causes of
acid rain.
• In the US, About 2/3 of all SO2
and 1/4 of all NOx comes from electric
power generation that relies on
burning fossil fuels like coal.
Acidic Precipitation
Primary Pollutants
SO2
NO2
Secondary Pollutants
H2SO4
HNO2
sulfuric acid nitric acid
acidic precipitation
Fossil fuels
Power plants
Industrial emissions
Auto emissions
vegetation
direct toxicity
indirect health effects
soils
leaching of minerals
water
sediments
leaching aluminum
Acidic
Precipitation
Wind
Transformation to
sulfuric acid (H2SO4)
and nitric acid (HNO3)
Windborne ammonia gas
and particles of cultivated soil
partially neutralize acids and
form dry sulfate and nitrate salts
Sulfur dioxide (SO2)
Nitric oxide (NO)
and NO
Acid fog
Ocean
Dry acid
deposition
(sulfur dioxide
gas and particles
of sulfate and
nitrate salts)
Wet acid deposition
(droplets of H2SO4 and
HNO3 dissolved in rain
and snow)
Farm
Lakes in
deep soil
high in limestone
are buffered
Lakes in shallow
soil low in
limestone
become
acidic
BIOL 349
Fig. 17.10, p. 428
Atmosphere
Sulphur dioxide emission (1997)
“Wet” Acid
Rain
• Acidic water flows over and
through the ground, it affects a
variety of plants and animals.
“Dry” Acid Rain
• Dry deposition refers to acidic
gases and particles.
• About half of the acidity in the
atmosphere falls back to earth
through dry deposition.
• The wind blows these acidic
particles and gases onto buildings,
cars, homes, and trees.
http://svr1-pek.unep.net/soechina/images/acid.jpg
Increased
Acidity
• Dry deposited gases and particles
can also be washed from trees and
other surfaces by rainstorms.
• The runoff water adds those acids to
the acid rain, making the
combination more acidic than the
falling rain alone.
Effects of Acid
Rain
• The strength of the effects depend on
many factors
– How acidic the water is
– The chemistry and buffering capacity
of the soils involved
– The types of fish, trees, and other
living things that rely on the water
Effects of Acid
Rain
• Has a variety of effects, including damage to
forests and soils, fish and other living things,
materials, and human health.
• Also reduces how far and how clearly we can
see through the air, an effect called visibility
reduction.
• Effects of acid rain are most clearly seen in
the aquatic environments
• Most lakes and streams have a pH between 6
and 8
http://cica.indiana.edu/projects/Biology/movies.html
Buffering Capacity
• Acid rain primarily affects sensitive
bodies of water, which are located in
watersheds whose soils have a
limited "buffering capacity“
• Lakes and streams become acidic
when the water itself and its
surrounding soil cannot buffer the
acid rain enough to neutralize it.
• In areas where buffering capacity is
low, acid rain also releases
aluminum from soils into lakes and
streams; aluminum is highly toxic to
many species of aquatic organisms.
http://home.earthlink.net/~photofish/fish_photos/sw10_thumb.jpg
Effects on Wildlife
• Generally, the young of most species are
more sensitive to environmental
conditions than adults.
• At pH 5, most fish eggs cannot hatch.
• At lower pH levels, some adult fish die.
• Some acid lakes have no fish.
Effects on Wildlife
• Both low pH and increased
aluminum levels are directly toxic to
fish.
• In addition, low pH and increased
aluminum levels cause chronic stress
that may not kill individual fish, but
leads to lower body weight and
smaller size and makes fish less able
to compete for food and habitat.
Acid Rain and Forests
• Acid rain does not usually kill trees
directly.
• Instead, it is more likely to weaken
trees by damaging their leaves,
limiting the nutrients available to
them, or exposing them to toxic
substances slowly released from the
soil.
Mongolia
Germany
Effects
of Acid
Rain
Great Smoky
Mountains, NC
Nutrients
• Acidic water dissolves the nutrients and
helpful minerals in the soil and then
washes them away before trees and other
plants can use them to grow.
• Acid rain also causes the release of
substances that are toxic to trees and
plants, such as aluminum, into the soil.
Air Pollution Prevention
Specific Air Pollution Treatment
Technology
• Traditional
– Move factory to remote location
– Build taller smokestack so wind blows pollution
elsewhere
• New
– Biofiltration : vapors pumped through soil where
microbes degrade
– High-energy destruction: high-voltage electricity
– Membrane separation: diffusion of organic
vapors through membrane
– Oxidation: High temperature combustor
Absorption
Adsorption
Combustion
Cyclone
Filtration
Electrostatic Precipitator
Liquid Scrubber
Sulfur Dioxide
Control
http://www.apt.lanl.gov/projects/cctc/factsheets/puair/adflugasdemo.html
Air Pollution Results
Comparison of 1970 and 1999 Emissions
Number of People Living in Counties with Air Quality
Concentrations Above the Level of the National Ambient
Air Quality Standards (NAAQS) in 1999
Trends in Sulfur Dioxide Emissions Following
Implementation of Phase I of the Acid Rain
Program: Total State-level Utility SO2 (1980, 1990,
1999)
Fifty
Years
of
Air
Pollution
30
VOC
20
Stationary
10
Mobile
0
CO
NOx
Figures are in millions of
metric tons per year
100
75
50
25
0
20
15
10
5
0
Stationary
Mobile
Stationary
Mobile
1940 1950 1960 1970 1980 1990
VOCs CO
NOx
Mobile
Sources:
The Last
Ten Years Percent reductions
-8%
-10%
PM10 SOx Lead
-3%
-29%
shown are based on
estimates of tons/year
from mobile sources
over the 1981 - 1990
time period
-24%
-85%
63
Who is
Affected by
Air
Pollution?
Over 74 million people are
subjected to high levels of at
least one of these pollutants
22
Ozone CO
19
9
1
NO2
5
PM10 SO2 Lead
Millions of people living in
counties with air quality that
exceeds each NAAQS (1990 data)
1952 - Autos linked to air pollution
Milestones
in the
Control
of
Automotive
Emissions
1963 - Original CAA, PCV valves
1968 - HC & CO exhaust controls
1970 - CAA amendments, EPA formed
1971 - Evaporative controls
1972 - First I/M Program
1973 - NOx exhaust controls
1975 - First catalytic converters
1981 - New cars meet statutory limits
1989 - Volatility limits on gasoline
1990 - New CAA Amendments
• 1987 Montreal Protocol: CFC
emissions should be reduced by 50% by
the year 2000 (they had been increasing
3% per year.)
• 1990 London amendments: production
of CFCs, CCl4, and halons should
cease entirely by 2000.
• 1992 Copenhagen agreements: phaseout accelerated to 1996.
What is the Kyoto Protocol?
How did we get to Kyoto?
What are the goals of Kyoto?
Is Kyoto enough?
Steps to Kyoto
1985 International Council of Scientific
Unions (Prof. Bert Bolin)
“Many important economic and social decisions are
being made today on long term projects, all based on
the assumption that past climatic data, without
modification, are a reliable guide to the future. This is
no longer a good assumption”
Steps to Kyoto
1988 - Toronto - creation of IPCC
warmest summer to date, international meeting in
Toronto
Intergovernmental Panel on Climate Change
formed
1990 - First report (FAR)
overview of the current science of climate change
IPCC
IPCC headed by Prof. Bert Bolin
3 working groups
Climate Science
Climate Impacts
Response Strategies
1992 - FAR used in Earth Summit meeting
in Rio - United Nations Framework Convention on Climate
Change
IPCC
1995 IPCC Second Assessment Report
(SAR) completed, published in 1996
WG I Climate Science
WG II Impact, Adaptation and Mitigation
WG III Economic and Social Dimensions
“The balance of evidence suggests a discernible human
influence on global climate”
IPCC
1997 Kyoto meeting - binding targets set
culmination of a series of meetings since Rio
(1992)
2001 Bonn - rescuing Kyoto
2001 IPCC Third Assessment Report
(TAR)
WG I Climate Science
WG II Vulnerabilities, Impacts and Adaptation
WG III Mitigation
IPCC
TAR (2001)
“There is new and stronger evidence that most of the
warming observed over the last 50 years is
attributable to human activities” (WG I)
Global losses in weather related natural disasters have
increased ten-fold from the 1960s to the 1990s, and
that a portion of this increase must be due to
increases in frequency and intensity of some extreme
events. (WG II)
“most of the opportunities to reduce emissions will come
from energy efficiency gains and in reducing release of
greenhouse gases from industry” (WG III)
Goals of Kyoto Protocol
Reduction of greenhouse gases to below
1990 levels:
5.2% world wide reduction on average by 20082012
6% for Canada by 2008-2012
When sufficient countries ratify the
Protocol (at least 55 countries comprising at least
55% of emissions), Protocol comes into effect
USA - 25% of emissions
Kyoto Emissions Agreement
Annex B Countries
Fossil-Fuel
CO2
Emissions
(million
metric
tonnes C)
1990
Non Annex B Countries
Bunkers
(million
metric
tonnes C)
Fossil-Fuel
CO2
Emissions
(million
metric
tonnes C)
Bunkers
(million
metric
tonnes C)
3851
78
2126
41
1991
3751
88
2306
41
1992
3663
92
2291
43
1993
3610
92
2341
48
1994
3607
92
2487
50
1995
3624
95
2607
52
1996
95
58
Source: Gregg Marland3674
and Tom Boden (CDIAC,
Oak Ridge2704
National Laboratory).
1997
3696
97
2775
61
1998
3690
100
2756
62
Greenhouse Effect - Conclusion
• Since 1700, humans have directly or
indirectly caused the concentration
of the major greenhouse gases to
increase
• Scientists predict that this increase
may enhance the greenhouse effect
making the planet warmer by 0.3 to
0.6 degrees Celsius
Cost of Regular Gasoline
• $3.80 – Great Britain
• $3.80 – The Netherlands
• $3.74 – Italy
• $3.69 – Belgium
• $3.62 – France
• $3.57 – Germany
• $3.20 – Japan
• $1.39 – United States
in U.S. dollars as of October 13, 1997
History of Global Warming
1904: Swedish scientist Svante
Arrhenius was, according to NASA,
"the first person to investigate the
effect that doubling atmospheric
carbon dioxide would have on
global climate."
History of Global Warming
Arrhenius began studying rapid
increases in anthropogenic – carbon
emissions, determining that "the
slight percentage of carbonic acid in
the atmosphere may, by the advances
of industry, be changed to a
noticeable degree in the course of a
few centuries."
History of Global Warming
The unique research of Arrhenius
suggested that this increase could be
beneficial, making Earth's climates
"more equable" and stimulating plant
growth and food production. Until
about 1960, most scientists thought it
implausible that humans could actually
affect average global temperatures.
History of Global Warming
1950s: Geophysicist Roger
Revelle, with the help of Hans
Suess, demonstrated that carbon
dioxide levels in the air had
increased as a result of the use of
fossil fuels.
History of Global Warming
1965: Serving on the President's Science
Advisory Committee Panel on
Environmental Pollution in 1965, Roger
Revelle helped publish the first high-level
government mention of global warming.
The book-length report identified many of
the environmental troubles the nation
faced, and mentioned in a "subpanel
report" the potential for global warming by
carbon dioxide.
History of Global Warming
1977: "In 1977 the nonpartisan
National Academy of Sciences issued a
study called Energy and Climate,
which carefully suggested that the
possibility of global warming 'should
lead neither to panic nor to
complacency.'
History of Global Warming
Rather, the study continued, it
should 'engender a lively sense of
urgency in getting on with the work
of illuminating the issues that have
been identified and resolving the
scientific uncertainties that
remain.'
History of Global Warming
As is typical with National Academy
studies, the primary recommendation
was for more research." — From
"Breaking the Global-Warming
Gridlock" by Daniel Sarewitz and
Roger Pielke Jr., THE ATLANTIC,
July 2000
History of Global Warming
Roger Revelle chaired the National
Academy Panel, which found that about
forty percent of the anthropogenic carbon
dioxide has remained in the atmosphere,
two-thirds from fossil fuel and one-third
from the clearing of forests. It is now
known that carbon dioxide is one of the
primary greenhouse gases that contributes
to global warming and remains in the
atmosphere for a century.
History of Global Warming
1980s: Representative Al Gore (DTN), who had been a student of
Revelle's, co-sponsored the first
Congressional hearings to study the
implications of global warming and
to encourage the development of
environmental technologies to
combat global warming.
History of Global Warming
1982: Roger Revelle published a
widely-read article in SCIENTIFIC
AMERICAN addressing the rise in
global sea level and the "relative
role played by the melting of
glaciers and ice sheets versus the
thermal expansion of the warming
surface waters."
History of Global Warming
1983: The Environmental
Protection Agency released a
report detailing some of the
possible threats of the
anthropogenic emission of
carbon dioxide.
History of Global Warming
1988: NASA climate scientist James Hansen
and his team reported to Congress on global
warming, explaining, "the greenhouse
warming should be clearly identifiable in the
1990s" and that "the temperature changes are
sufficiently large to have major impacts on
people and other parts of the biosphere, as
shown by computed changes in the frequency
of extreme events and comparison with
previous climate trends."
History of Global Warming
With the increased awareness of global
warming issues, the Intergovernmental Panel
on Climate Change (IPCC) was established by
the World Meteorological Organization and the
United Nations Environment Programme to
assess scientific, technical and socio-economic
information relevant for the understanding of
climate change, its potential impacts and
options for adaptation and mitigation. The
IPCC was the first international effort of this
scale to address environmental issues.
History of Global Warming
1990: Congress passed and President George
Bush signed Public Law 101-606 "The Global
Change Research Act of 1990. The purpose of the
legislation was "…to require the establishment of
a United States Global Change Research
Program aimed at understanding and
responding to global change, including the
cumulative effects of human activities and
natural processes on the environment, to
promote discussions towards international
protocols in global change research, and for
other purposes."
History of Global Warming
•As part of the Act, the Global Change
Research Information Office (GCRIO) was
established "to disseminate to foreign
governments, businesses, and institutions,
as well as citizens of foreign countries,
scientific research information available in
the United States which would be useful in
preventing, mitigating, or adapting to the
effects of global change. The office began
formal operation in 1993.
History of Global Warming
1992: In June of 1992, over 100
government leaders, representatives
from 170 countries, and some 30,000
participants met in Rio de Janeiro at
the U.N. Conference on Environment
and Development (UNCED or the
"Earth Summit").
History of Global Warming
There, an international assembly
formally recognized the need to
integrate economic development and
environmental protection into the goal
of sustainable development.
History of Global Warming
1997: In December, 1997, more than
160 nations met in Kyoto, Japan, to
negotiate binding limitations on
greenhouse gases for the developed
nations, pursuant to the objectives of
the Framework Convention on Climate
Change of 1992.
History of Global Warming
The outcome of the meeting was the
Kyoto Protocol, in which the developed
nations agreed to limit their
greenhouse gas emissions, relative to
the levels emitted in 1990. The United
States agreed to reduce emissions from
1990 levels by 7 percent during the
period 2008 to 2012.
History of Global Warming
1997: In December, 1997, more
than 160 nations met in Kyoto,
Japan, to negotiate binding
limitations on greenhouse gases for
the developed nations, pursuant to
the objectives of the Framework
Convention on Climate Change of
1992.
History of Global Warming
The outcome of the meeting was the
Kyoto Protocol, in which the
developed nations agreed to limit their
greenhouse gas emissions, relative to
the levels emitted in 1990.
The United States agreed to reduce
emissions from 1990 levels by 7
percent during the period 2008 to
2012.
History of Global Warming
Also that year, the United States Senate
unanimously passed the Hagel-Byrd
Resolution notifying the Clinton
Administration that the Senate would not
ratify any treaty that would (a) impose
mandatory greenhouse gas emissions
reductions for the United States without
also imposing such reductions for
developing nations, or (b) result in serious
harm to our economy.
History of Global Warming
2001: The IPCC released its third
assessment report, concluding on the
basis of "new and stronger evidence that
most of the observed warming over the
last 50 years is attributable to human
activities." They also observed that "the
globally averaged surface temperature is
projected to increase by 1.4 to 5.8 degrees
Celsius over the period 1990 to 2100."
History of Global Warming
The same year, President George
W. Bush announced that the United
States would not ratify the Kyoto
Protocol. The Protocol is now in
limbo until one of the two crucial
holdouts — Russia or the United
States — will ratify the treaty.
History of Global Warming
2003: Senator John McCain (RAZ) and Senator Joseph
Lieberman (D-CT) co-sponsored
a proposal for mandatory caps
on "greenhouse gas" emissions
from utilities and other
industries.
History of Global Warming
Although the proposal was rejected
in the Senate by a margin of 55 to
43, it was the Senators' first
attempt to garner Senate attention
for the issue of global warming, and
McCain and Lieberman were
encouraged by the support for the
measure.