Transcript Photochemical Activity within the Surface Snowpack:

How Humans Affect the Atmosphere:
Air Pollution and its Impacts
Weather & Atmosphere – Meeting the Benchmarks
CCISD, Hancock, MI
Feb 15, 2002
Richard E. Honrath
Dept. of Civil & Environmental Engineering
Michigan Technological University
The major air pollutants
• Carbon monoxide (CO)
• Nitrogen oxides (NOx)
• Ozone (O3)
• Particulate matter (PM-10, PM-2.5)
• Sulfur dioxide (SO2)
• Lead (Pb)
• Greenhouse gases (CO2 and others)
Carbon Monoxide
• Impacts: Blood oxygen levels
Hb + O2 <-> HbO2 K1 = Equilibrium constant
Hb + CO <-> HbCO K2 = 210 x K1
• Headaches, alertness, death
• Sources: Vehicles (plus others)
Source: Ref. (1)
Carbon Monoxide
• CO levels are improving, but still a problem
in many colder urban areas.
Source: Ref. (1)
Nitrogen Oxides
•
•
NOx = NO + NO2
Impacts: Respiratory irritant (NO2)
(but AQ standard seldom violated)
- Leads to ozone formation
- Leads to acidic deposition of HNO3
Nitrogen Oxides
•
•
NOx = NO + NO2
Impacts: Respiratory irritant (NO2)
- Leads to ozone formation
- Leads to acidic deposition of HNO3
• Sources: High-temperature combustion
N2 + O2  2NO
Source: Ref. (1)
Ozone
• Impacts:
- Respiratory irritant
- Plant damage (forest, crops) (FACE site)
- Oxidizes C=C double bonds: rubber
• Sources:
-Produced in the atmosphere
NOx + VOCs + sunlight -> NOx + O3
Ozone
• A major urban and regional pollution problem
Source: Ref. (1)
Particulate Matter
• Definitions:
- PM10 = PM < 10 um
- PM2.5 = PM < 2.5 um
• Impacts:
- Lung irritation
- Visibility
Particulate Matter
• Impacts:
- Lung irritation
- Visibility
• Sources: Depends on particle size
Source: Ref. (1)
Particulate Matter
• Impacts: Visibility at Shenandoah Nat’l Park
Source: Ref. (2)
Sulfur Dioxide
• Impacts:
- Eye and lung irritation (but seldom > standard)
- Acidic deposition of H2SO4.
- Damage to limestone and concrete.
• Sources: S in fuel is emitted as SO2
Source: Ref. (1)
Sulfur Dioxide
• Impacts: Acidic deposition of H2SO4.
Pure
water
pH = 5.6
Lead
• Impacts: Brain and kidney damage.
• Sources: Leaded gasoline was dominant,
but Pb is no longer in U.S. on-road gasoline
Source: Ref. (1)
Lead
• Impacts: Brain and kidney damage.
• Sources: Metals processing, battery mfr, etc
Source: Ref. (1)
Greenhouse Gases
• Impacts: Global climate change
• Gases:
• Sources:
See : Ref. (4)
The Greenhouse Effect
What determines the average temperature of the earth?
The Greenhouse Effect
What determines the average temperature of the earth?
1.
Source: Ref. (5)
The Greenhouse Effect
What determines the average temperature of the earth?
2.
The Greenhouse Effect
What determines the average temperature of the earth?
3.
The Natural Greenhouse Effect
• Average solar radiation in:
236 W per square m
The Natural Greenhouse Effect
• Average solar radiation in:
236 W per square m
• Without the atmosphere, temperature would be:
-2 F
The Natural Greenhouse Effect
• Average solar radiation in:
236 W per square m
• Without the atmosphere, temperature would be:
-2 F
• Greenhouse effect of natural water and CO2:
148 W per square m
(1 lightbulb every 2 feet)
• Result: Average temperature =
57 F
The Human Contribution
Source: Ref. (6)
The Human Contribution
• Total effect until now: about 2.3 W / m2
(1 light bulb every 15 feet)
• Predicted effect by 2050: Up to 7 W / m2
(1 light bulb every 9 feet)
What happens if
we add 3 to 7 W / m2
to the earth’s atmosphere?
Recent Trends in Temperature
Source: Ref. (6)
Expected Impacts:
More precip, more energy in weather
• More extreme weather events are predicted
• On average, more precipitation, but
region-by-region, some will be wetter, some
drier.
Long-term
Impacts:
Models predict
changes in
climate
Two climate models
predict Illinois climate
in 2030 and 2090.
Source: Ref. (7)
CO2 Emissions by Nation
Developing nations
will soon be the largest
CO2 producers, but
most CO2 in the
atmosphere today came
from to industrialized
nations
Source: Ref. (8)
Emissions
by Sector
CO2 Emissions
by Nation
Easiest mitigation
measure =
energy efficiency
Household emissions
See : Ref. (4)
Particulate Activities
1. Light scattering
- Particles most effectively scatter light
of wavelength ~ particle diameter.
- Uncontrolled car exhaust scatters blue light.
- Atmospheric gases also scatter, blue more
than red.
- Large concentrations of particle mixtures
scatter all colors  white haze
Haze in Los Angeles
Source: Ref. (9)
Particulate Activities
See Ref. (10)
1. Sky Blue, Sunset Red
- Start with jar of clean water.
- Demonstrate no scattering:
- Shine light beam through – cannot see it
from the sides, color at exit is white.
- Add milk a little at a time
- Observe effect on scattering: beam
becomes visible, color at exit reddens,
color from sides becomes bluish.
- View an object through the jar:
- Starts visible, becomes invisible: Haze.
Particulate Activities
1. Sky Blue, Sunset Red
Key points:
- Why is the sky blue?
- Why is the sunset red?
- Why does the sunset get redder when there
are fires or pollution?
- Why are far-away objects invisible in
smoggy places?
Particulate Activities
See Ref. (10)
1. Air Strips
- Obtain samples of particles and observe
using magnifying glasses or microscopes.
- Discuss local particle sources.
Notes
- Will only be able to see larger particles, like
plant materials, dusts, or major smokes
- Best to do during fall when more large
particulates are in the air.
Local Issues
1. Vehicle emissions
- Sources of CO, CO2, particulates, NOx,
VOCs
- Strategies for reducing emissions
 Fuel economy (all, proportional to fuel
use)
 Catalytic converters and no exhaust
system leaks (CO, NOx, particulates,
VOCs – no effect on CO2)
Local Issues
See Ref. (10)
1. Vehicle emissions
- Activity: Let’s Sock Car Exhaust
- Use tube socks to collect particles from
vehicle exhaust.
- Notes:
- Connect when vehicle is cold, run 5 min,
let cool 5 min, remove, turn inside out.
- Fuel is incompletely burned, and catalytic
converters do not function, during 1st 5
minutes with cold engine.
- Observe the socks outside (fuel on them)
Local Issues
1. Vehicle emissions
- Activity: Let’s Sock Car Exhaust
- Key points:
- Emissions will relate directly to engine
size (amount of fuel burned in 5 min).
- Emissions will vary with age and
maintenance.
- Only particles are collected: CO, NOx,
gaseous VOCs, CO2, water vapor are
not.
Local Issues
2. Snowmobiles and wood stoves
- Snowmobiles: 2-cycle engines are light, but
of the C burned,
- ~1/3 is fully burned and emitted as CO2.
- ~1/3 is emitted as CO.
- ~1/3 is not burned at all and released as
gasoline.
Local Issues
2. Snowmobiles and wood stoves
- Wood stoves:
- Newer wood stoves have catalysts or
secondary combustion;
- those without emit more particles and
VOCs
- Can compare by viewing chimney
exhaust (don’t be fooled by water fog)
- Wood stoves can be a major source of
indoor air pollution when smoke is pulled
in from outdoors.
Local Issues
3. Indoor air pollution
Key issues:
- Radon
- Molds
- Particles and smokes
Local Issues
4. Atmospheric Dispersion
- Radiative cooling on clear nights -> cold
ground under warmer air.
- Air flow over Lake Superior during summer
-> cold water under warmer air.
The Effect of Temperature on Air Mixing
Temperature increasing with height
Warm Air over Cold Water
Source: Ref (11)
Cold Air over Warm Water
Source: Ref (11)
Lake Superior
Average
Temperatures
Percent Icefree
Source: Ref (12)
Fog forming over warm Portage Lake
Inversions over L.A.
Local Issues
5. Airborne pollutants and fishing advisories
• PCBs: “PolyChlorinatedBiphenyls”
• Chemically stable, thermally stable, high
dielectric constants.
• Used in transformers, as hydraulic
fluids, …
PCBs
• “PolyChlorinatedBiphenyls”
• Used in transformers, as hydraulic
fluids, …
• Chemically stable, thermally stable, high
dielectric constants.
• Not broken down in the environment.
• Accumulate in animal fats.
• Cause birth defects.
• Manufacture in U.S. banned in 1977.
PCBs in the Environment
Source: Ref. (13)
PCBs in Lake Superior
• The atmosphere is the main source.
• The atmosphere is also a main sink.
Impacts in the Great Lakes
• Wildlife effects (fish-eating birds):
– crossed beaks,
– embryo deaths,
–…
• Human effects (children of mothers who ate
large amounts of Great Lakes fish):
– behavioral and developmental defects
– sperm counts
• Fish advisories
Stratospheric Ozone
Strat vs Trop O3
Source: Ref (12)
Stratospheric Ozone
Ozone destruction
Source: Ref (12)
Stratospheric Ozone
Antarctic ozone hole
Source: Ref (12)
Stratospheric Ozone
Antarctic ozone hole
Source: Ref (13)
Stratospheric Ozone
Declining outside of Antarctica
Source: Ref (5)
Stratospheric Ozone
Impact on UV radiation
Source: Ref (5)
Stratospheric Ozone
Success of the Montreal Protocol
Stratospheric Ozone
Some common questions
• CFCs are heavier than air, so cannot
reach the stratosphere.
• The ozone hole is natural, and is caused
by volcanoes and oceans.
• Ozone depletion occurs only over
Antarctica.
Tropospheric Ozone
Chemistry in Los Angeles air
NOx + Hydrocarbons + sunlight =
Ozone (O3)
This photo shows haze – ozone is
invisible but haze commonly occurs at the
same time as high ozone levels.
Roles of Ozone in the Lower Atmosphere
• Human health effects (urban and
rural).
• Causes forest and crop damage
(regional).
Ozone is an issue in urban areas
and in large regions
Source: Ref (17)
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18)
Sources
EPA, National Air Quality and Emissions Trends Report, 1999. EPA 454/R-01-004, March 2001.
http://www.epa.gov/oar/aqtrnd99/
U.S. National Park Service, March 2001, http://www2.nature.nps.gov/ard/vis/visimpair.html.
National Acid Deposition Program (NRSP-3)/National Trends Network, NADP Program Office, Illinois State Water
Survey, 2204 Griffith Dr., Champaign, IL, 61820, http://nadp.sws.uiuc.edu/isopleths/.
Data available in U.S. EPA,Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2000, USEPA 236-R02-003, http://www.epa.gov/globalwarming/publications/emissions/us2002/index.html.
Our Changing Planet: The FY 1996 U.S. Global Change Research Program, A Report by the Subcommittee on
Global Change Research, Committee on Environment and Natural Resources Research of the National Science
and Technology Council, A Supplement to the President’s Fiscal Year 1996 Budget (see
http://www.gcrio.org/online.shtml)
Ledley et al., Eos Transactions, 80, 39, p. 453, 1999.
Climate Change Impacts on the United States: The Potential Consequences of Climate Variability and Change,
National Assessment Synthesis Team, US Global Change Research Program, 2001. (See Chapter 6 at
http://www.usgcrp.gov/usgcrp/Library/nationalassessment/foundation.htm)
B. Hileman, Global Climate Dchange, C&E News, p. 11, Nov 17, 1997.
O. E. Allen, Atmosphere, Time-Life Books, 1983.
Environmental Resource Guide, Air Quality, Grades 6-8. Air and Waste Management Association (see
http://www.awma.org/pubs/bookstore/).
W. A. Lyons, Turbulent diffusion and pollutant transport in shoreline environments, in Lectures on Air Pollution and
Environmental Analyses, American Meteorological Society, pp. 136-208, Boston, Mass, 1975.
R. E. Honrath, C. I. Sweet, and C. J. Plouff, Environ. Sci. & Tech., 842-852, 1997.
F. Wania and D. Mackay, Environ. Sci. & Tech., 390A-396A, 1996.
EPA Ozone Science web site: http://www.epa.gov/ozone/science/
NOAA Climate Prediction Center, http://www.cpc.ncep.noaa.gov/products/stratosphere/sbuv2to/index.html.
British Antarctic Survey, http://www.antarctica.ac.uk/met/jds/ozone/ozpamw7.htm.
NOAA Aeronomy Laboratory; J. Geophys. Res., 101, D22, cover, 1996.
Our Changing Planet: The FY 1997 U.S. Global Change Research Program, (see
http://www.gcrio.org/online.shtml)