AIR AND AIR POLLUTION

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CHAPTER 10

• AIR AND AIR POLLUTION

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When 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

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The 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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The 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

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The 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

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Urban 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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Urban 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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Formation 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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Formation 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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Air 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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Areas 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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Effects 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

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Effects 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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How 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

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How 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

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How 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

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Indoor 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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Radon 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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Radon 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

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Asbestos 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

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Air 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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Air 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

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Plant 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

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Aquatic 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

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Solutions 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

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Solutions 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

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Solutions 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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To 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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Reducing 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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Integrated, 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