Matakuliah
Tahun
: S0782 - Teknik Lingkungan
: 2009
AIR POLLUTION
CHAPTER 8
Air Pollution
Bina Nusantara
Introduction
•
Currently only two real problematic
classes of pollutants
–
–
•
•
•
•
•
Non-point source agricultural pollution
Air quality
Difficult to control because air flows in all
directions (air shed)
Difficult to perform bioassay
Easier to control front end (decrease
generation of polluted air) than back end (clean
up polluted air)
Like water pollution, originates in one place,
impact another place (unlike soil pollution).
Most air pollution due to use of E.
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Major Sources of Air Pollution
Residential fuel combustion,
farming operations,
construction, road dust, windblown dust,
Sources of all air pollutants
measured in California*
(Hydrocarbons, Carbon Monoxide,
Oxides of Nitrogen, Oxides of
Sulfur and Particulate Matter)
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Source: California Department of Consumer Affairs,
Bureau of Automotive Repair
Regulations – Clean Air Act
•
Based on impact over a large area but low impact over any one
area
A.
Goal – maintain air quality to protect human health and welfare (=
environment)
1. Two stage protection scheme
a. Human health at work
b. Widespread environmental controls
2. Two primary sources of air pollution (complex problem)
a. smoke stacks (power plants, manufacturing)
b. mobile sources (auto’s  California acid rain)
note: NE corridor/Los Angeles = 70% of problem
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Regulations – Clean Air Act (con’t)
B. Policy – maintain “safe” outdoor concentrations of pollutants
hazard = exposure X effect
/
\
\
conc. x duration
LC50, etc
C. Strategies
1. Regional air quality plan – if pollution levels go up  deny new stack
permits and/or alter flow of transportation
2. Emission control standards - reduce air pollution using Best Available
Control Technology (BACT)
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Regulations – Clean Air Act (con’t)
•
BACT
-
Front end control
Compromise between function and cost effectiveness - zero emissions possible
but too expensive
A.
BACT for auto’s (mobile source control)
- emission control devices (eg catalytic converter) ~ $700 each because platinum (most
expensive precious metal)
- mileage standards (fleet mileage goals  never reached)
Note: gas was cheap so no incentive (abandoned by Reagan, Bush Sr, most recently Bush Jr
 wants us to “conserve”). Now gas is not cheap, and US is major contributor to global
CO2 increase
B.
BACT for stationary sources (smokestacks, dry cleaning)
- sulfur scrubbers  expensive  so try to use low sulfur coal (S is high in eastern coal,
low in western coal
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Examples of reduction in air pollution after passage of Clean Air Act
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Some air pollution is not regulated
Wishful
thinking
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More unregulated air pollution - burning rice stubble in
Poinsett Co., Arkansas
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Photo by R. Grippo
Air
pollution
in India
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Photo by R. Grippo
Policeman directing
traffic in India
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Photo by J. Farris
Major Air Pollutants
- mostly coal-plant generated
A.
Suspended particulates
- Most common, oldest problem addressed
1. Trace rock from burning pulverized coal (unburnable residues)
2. Fly ash from coal (contains Cd, Cu, Pb, Se, As, Hg) has high volume  control
by electrostatic precipitators
3. Carbon/soot from diesel
B.
Gasses
1.
SO2
- respiratory inhibitor
- plant leaf injury
- decreases N fixation in bacteria
- oxidizes to SO3 (sulfur trioxide)  H2SO4
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B. Gasses (con’t)
2. Oxidants (O3 )
- in atmosphere  not enough
- at ground level  too much  comes from
hydrocarbons (gasoline) + O2 = O3
- also a respiratory aggravator
- leaches nutrients from soil  lower primary
productivity  less carbon fixed 
increase greenhouse effect
3. Nitrogen oxides (NOx )
- N2O nitric acid – comes from atm N (atm =
80% nitrogen)
- NO2 nitrous oxide (ha, ha!)
- respiratory aggravator
- decreases soil pH  reduces soil
micronutrient availability to plants
- NO2 + H2O = HNO3 = brown haze = smog
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Photo courtesy U.S. EPA
B. Gasses (con’t)
4. Carbon oxides
- CO monox  competes with O2 binding on hemoglobin (affinity is 200X O2 )
- CO2 dioxide = greenhouse effect
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Minor Gaseous Air Pollutants
Low in direct effects, high in indirect effects
CFC’s (Freon)
1.
–
–
–
–
2.
Principal refrigerant (a/c, refrigerators)
Catalyze destruction of ozone
Ozone forms protective layer around earth  partially blocks UV
Montreal Accord (1990) – supposed to phase out CFC’s by 2000 (not completely done
yet)
Halon
–
–
3.
Related to CFC
Used in fire extinguishers
Carbon tetrachloride and Methychloroform
–
–
Dry cleaner solvents
Manufacturing processes
All above compounds catalyze the destruction of ozone
Recall: catalyzers participate in a reaction but are not consumed  hang
around a long time (1/2 life of several years) and continue to reduce
ozone
•
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Therefore, if stopped using now  good effects would take many
years to appear
Ozone Depletion Capacity of Commonly Used Chemicals
Chemical
CFC-11
CFC-12
CFC-113
Halon
1211
Halon 1301
Atmospheric
Lifetime (yrs)
Share of Contribution
to Depletion (%)
76
139
26
45
92
12
101
Carbon
tetrachloride
67
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12
1
4
8
Characteristics of
Greenhouse Gasses
CO2
Atm contribution
Potential GH effect
346
CH4
1.65
N2O
0.31
0.02
O3
0.0002
CFC-11
0.00032
1
32
150
2000
14,000
17,000
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Note: Up to 1970  CO2 dominated  by 1980
dominance decreased  by 2020  other gasses
dominate. Result in predicted increase of 0.5º to 3º C
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CFC-12
Indoor Air Pollutants
• Includes SO2, NOx, CO, CO2 (coal furnace, kerosene heater
especially if burn out
• Formaldehyde
– Common constituent of building material
– Many health effects (humans very sensitive
• Respiratory aggravator
• Potential carcinogen
• “sick building syndrome” – formaldehyde volatilizes from building mat’l
(including adhesives)  trapped inside because buildings are airtight to
increase E. efficiency  people get sick
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Non-industrial, non-regulated
sources of in-door air pollution
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Source: AirAdvice, Inc.
Summary of Major Air Pollutants
• Burning fossil fuels = air pollution
• Coal  sulfur  acid rain
• Cars  NOx - “ “ , haze
Approximately 10,000,000 premature deaths/year world-wide
are attributable to stationary and mobile air pollution
sources
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The least lethal
form of energy
production
Sharon
Harris
nuclear
power plant,
NC
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Photo by R. Grippo