Title: AIR AND AIR POLLUTION
1CHAPTER 10
2When is a lichen like a canary?
- Lichens are hardy pioneer species
- Fungus and algae coexist in mutually beneficial
relationship - Some are susceptible to specific air polluting
chemicals - Radioactive fallout contaminated reindeer moss (a
lichen) near Chernobly reindeer meet became
radioactive
3The Atmosphere Trophosphere
- Closest and densest air mass is trophosphere
- Thin layer - 17 km - moving air currents
- Gas composition Nitrogen 78, Oxygen
21, CO2, argon and other gases including water
vapor - Density, and therefore pressure, decrease with
altitude temperature drops until the trophopause
(prevents trophosphere and stratosphere air mixing
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5The Atmosphere Stratosphere
- Less dense farther away - 17 - 48 km
- Little air movement and therefore mixing
- Similar gases, but less of each except 1000 x
as much ozone - Ozone filters out 96 harmful UV radiation
- protective making life possible
- prevents conversion of oxygen into bad ozone
-
6The Atmosphere 2 important natural processes
- Greenhouse effect - helps to heat trophosphere
- Ozone shield in stratosphere filters out suns UV
radiation - Anthropogenic chemicals
- enhance natural greenhouse effect --gt global
warming - reduce ozone --gt ozone depletion
7Urban outdoor air pollution from smog
- Primary pollutants - products of natural events
and human activities dispersed within churning
trophosphere - Secondary pollutants - formed by reactions
between primary pollutants - Pollutants stay suspended, move large distances
and return to earth - Mix with pollutants originating inside buildings
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9Urban outdoor air pollution from smog
- Stationary sources of pollutants
- power plant and factory emissions
- Mobile sources
- motor vehicles emission (88 of pollution)
- Photochemical smog formed by action of sunlight
on primary and 2ndary pollutants - Biggest problem in cities on sunny days
- Industrial smog - SO2 in H2SO4 droplets
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11Formation of photochemical and industrial smog
- Frequency and severity depend upon
- local climate and topography
- population density
- amount of industry
- fuels used in heating, industry transportation
- Hills block air flow --gt pollution buildup in
valleys - Pollutants rise with warm air, mix fall again
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13Formation of photochemical and industrial smog
- Thermal inversion - cool dense air trapped below
warm air in valley air does not mix and dilute
pollutants - may become lethal - Characteristics of thermal inversion areas
- Population of millions, many cars, sunny, light
winds, mountains on 3 sides, ocean on 4th side - Donora, Penn, Los Angeles, Denver, Mexico City,
Rio de Janeiro, Sao Paulo, Shenyang
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15Air pollution from acid deposition
- Tall smokestacks put emissions above inversion
layer --gt local pollution to meet regulations - Wind carries emissions --gt increases pollution
downwind - Nitrogen oxides and sulfur oxides form secondary
pollutants react to form acid rain - Acids (low pH) ---pH7 ---Bases (high pH)
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17Areas with acid deposition
- Areas downwind from coal-burning
- Contain thin, acidic soils, little buffering
- Long exposure to acid has depleted buffers
- Acid deposition may travel to other countries
- Developing countries producing increasing amounts
of acid deposition
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19Effects of Acid Deposition
- Mountain-top forests - thin soil evergreens
- Trees weakened by acid deposition and other
pollutants susceptible to other damage - Other stresses on susceptible trees
- cold temperature and drought
- diseases, insects and fungi
- loss of soil nutrients -less primary productivity
- Results in loss of biodiversity
20Effects of Acid Deposition -2
- Nitrogen compounds not taken up by plant roots as
nutrients - Acids release aluminum ions attached to soil
minerals - Acids can convert inorganic mercury into highly
toxic organic (methyl) mercury
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22How serious a problem?
- Studies show acid deposition declined in some
areas but - Acid deposition has spread to new areas
- Must further reduce sulfate and nitrate emissions
- U.S. coal companies say it costs too much! Oppose
Clean Air Act,1990 standards
23How to reduce acid deposition
- Prevention approaches
- improve energy efficiency - reduce energy use
- switch from coal to natural gas
- remove sulfur from coal before burning
- burn low-sulfur coal
- remove harmful gases from smoke-stack gases
- remove nitrogen oxides from auto emissions
- tax sulfur dioxide emissions
24How to reduce acid deposition -2
- Clean-up approaches
- Neutralized acidified lakes with lime (high pH)
- Problems with liming
- expensive and only temporary
- kills some plankton and aquatic plants
- lime dose difficult to ascertain
- can affect soil microbes
- Possibly us phosphate fertilizer
25Indoor Air Pollution
- Some pollutants greater inside (where many people
spend majority of time) than outside - outside pesticides move to inside
- pollutants may cause cancer - esp. high risk
- sick building syndrome due to chemicals in
furnishings and poor air exchange - top pollutants cigarette smoke, formaldehyde
(see list) and radioactive radon-222 gas - asbestos and fiberglass
- cooking smoke in developing countries
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27Radon Danger
- Uranium-238 naturally decays to Radon-222
- Radon gas enters buildings through foundation and
wall cracks, openings around drains, and hollow
concrete blocks - Danger of lung cancer depends on
- amount of radon in home
- amount of time spent in home
- time spent smoking
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29Radon Danger
- Considered leading cause of lung cancer after
smoking - But what is threshold dose? 4 picocuries?
- Radon testing and correcting - very expensive
- Only 6 of homes conducted tests by 99
30Asbestos Danger
- Fibrous form of silicate material used in
building due to strength, flexibility, cheap - Dust of fibers inhaled - lodge in lungs --gt
asbestosis, lung cancer and mesothelioma - Most affected -those who worked with asbestos and
families--gt premature deaths - Most uses were banned much removed at great
cost - still mined used in developing countries
31Air pollution and living organisms
- Human respiratory system protectors
- nose hairs, mucous membranes with cilia
- sneezing and coughing
- Smoking and pollutants damage protectors
- lung cancer
- asthma
- chronic bronchitis
- emphysema
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33Air pollution and living organisms
- Carbon monoxide (CO) binds to hemoglobin which
then cant carry oxygen - Suspended particulate matter
- Sulfur dioxide - coal
- Nitrogen oxides - burning fossil fuels volatile
organic compounds - Ozone
- How many die early - a full jumbo jet/day
34Plant damage by pollution
- Evergreens damaged by ozone - evidence slow
- depletion of soil nutrients
- increased susceptibility to pests
- High elevation forests - Appalachian
- Crop damage corn, wheat, and soybeans
- Reduction in food production
35Aquatic life damage by pollution
- Acid lakes with little buffering ability
- Acid shock - from sudden runoff into lake of
acidified water and aluminum ions - Kill fish inhibit reproduction --gt disruption
of food chain --gt decreased net primary
productivity - Effect on materials - buildings and statues
deteriorate
36Solutions Preventing and reducing air pollution
- Use of laws
- Clean Air Acts of 1970, 1977 and 1990 provide
federal air pollution regulations enforced by
states - Requires EPA to set ambient air quality standards
(NAAQS) for seven pollutants - Pollutant levels declined in spite of increasing
population but - Air continues to be too toxic
37Solutions Preventing and reducing air pollution
- improved laws?
- Deficiencies in laws
- too much reliance on cleanup than on prevention
- fuel efficiency standards not strict enough
- no standards for fine particulates
- 30 year permits for municipal incinerators
- weak standards for incinerators
- carbon dioxide emissions not reduced enough
38Solutions Preventing and reducing air pollution
- market place
- Pollution credits/rights - transferred
- should credits be lowered?
- Are older, dirtier power plants buying time?
- Incentives to cheat with self-reporting
- renovated plants continue to pollute as before
- But, pollution reductions that have occurred have
not been as expensive as believed
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40To further reduce air pollution
- More emphasis on prevention
- Taxes on air pollutant emissions
- New 1 second highway test for auto emissions
- Get old cars off the road
- Californias South Coast Air Quality Management
District Council program- look at five parts
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43Reducing indoor air pollution
- No need to impose indoor air quality standards
and monitor homes - But fig 10-17 gives examples
- Also, rooftop greenhouses for air circulation
- Efficient cook stoves in developing countries
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45Integrated, Global Approach
- pollution prevention emphasis
- improve energy efficiency
- less fossil fuels more renewable energy use
- slow population growth
- integrate economic and trade policies
- widespread regulation of air quality
- full-cost pricing
- energy efficient technologies to developing
countries