AIR-EIA was funded under INFO2000
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air pollution and environmental impact assessment:
the multimedia information source

What is "Air"?

Air is a non-homogenous mixture of gases, solid particles, and liquids; It consistes of gases and particles with small settling velocity that exhibit stability in a gravitational field.

Atmosphere layers

Troposphere 0-17 kilometers (¾ 11 miles)
Stratosphere 17-50
Mesosphere 50-90
Ionosphere 90-100
95% of the air by weight is contained in the Troposphere.

Nominal Composition

Major Components (99%) in % by w or fraction of total molecules*

Component Percentage by Weight Fraction of Total Molcules
N2 75.51 0.7808
O2 23.14 0.2095
40Ar 1.28 0.0093
Water Vapor   0.0004
* Fractions of total molecules

Minor Components

Component ppm (parts per million**)
Carbon dioxide CO2 325.0
Ne 18.0
He 5.0
CH4 2.0
Kr 1.0
H2 0.5
N2O 0.5
Xe 0.1
** 325 ppm means that 325 of each 1 million particles is CO2

Outdoor Air Pollutants

Sources and Types:

  1. Carbon Oxides

  2. Carbon Monoxide (CO) & Carbon Dioxide (CO2)
  3. Sulfur Oxides

  4. Sulfur Dioxides (SO2) & Sulfur Trioxide (SO3)
  5. Nitrogen Oxides

  6. Nitric Oxide (NO), Nitrogen Dioxide (NO2), & Nitrous Oxide (N2O)
  7. Volatile Organic Compounds (VOCs)

  8. Most organic compounds - Example: Methane (CH4), Methanol (CH3OH), Benzene (C6H6), Chlorofluorocarbons (CFCs), formaldehyde (CH2O), Propane (C3H8).
  9. Suspended Particulate Matter (SPM)

  10. Solid and Liquid Particles both suspended in air. Example: dust soot, pollen, asbestos, ash, conglomerates, soil, salts, etc.
  11. Photochemical Oxidants

  12. Ozone (O3), Peroxide (H2O2), Hydroxide radicals (HO), aldehydes, etc. induced by electromagnetic energy from the Sun.
  13. Radioactive Isotopes

  14. Radon-222, Iodine-131, Strontium-90, Plutonium-239, Potassium-40, as gases and suspended particles.
  15. Heat

  16. Waste energy from fossil fuels; most energy sources and uses produce waste energy as heat, Example: cars, power plants, factories, homes.
  17. Noise

  18. A byproduct of energy used in airplanes, cars, industry, lawn mowers, mechanical byproduct, radios, wind, electrical power line discharge, communications (electromagnetic overlap and clutter in communications).

Primary Pollutants (Anthropogenic)

  • CO Carbon Monoxide
  • CO2 Carbon Dioxide
  • NO Nitrogen Monoxide
  • NO2 Nitrogen Dioxide
  • SO2 Sulfur Dioxide
  • Hydrocarbons (HCs)
  • Suspended Particulates Matter (SPM)

Secondary Pollutants

  • SO3 Sulfite
  • HNO3 Nitric Acid
  • H2SO4 Sulfuric Acid
  • H2O2 Hydrogen Peroxide
  • O3 Tropospheric ozone

Outdoor Air Pollutants

Greenhouse Gas Emissions

Anthropogenic compositional alterations to the atmosphere:
From 1989 Compilation (from United Nations Reference)
Carbon Dioxide (C02)
Emissions from Industrial Processes
(Anthropogenic Sources)
Total Metric Tons Per Capita (Metric Tons)
World 21,863,088,000 4.21
By World Region :
Asia 5,812,064,000 1.93
North and Central America 5,760,830,000 13.60
Europe 4,347,794,000 8.74
USSR 3,804,001,000 13.30
Africa 647,352,000 1.03
South America 557,298,000 1.91
Oceannia (Australia, Fiji, etc.) 291,248,000 11.20

Methane CH4
Greenhouse Gas Emissions
from Anthropogenic Sources
Total Metric Tons
World 270,000,000
By World Region :
Asia 130,000,000
North and Central America 45,000,000
Europe 26,000,000
USSR 34,000,000
Africa 19,000,000
South America 18,000,000
Oceannia (Australia, Fiji, etc.) 6,200,000

Emissions of Chlorofluorocarbons (CFCs)
Total Metric Tons
World 580,000
By World Region :
Asia 140,000
North and Central America 150,000
Europe 180,000
USSR 67,000
Africa 16,000
South America 15,000
Oceannia (Australia, Fiji, etc.) 9,000

Ozone depletion is the main effect, remember on average
each Cl atom destroys 100,000 (105) O3 molecules.
Emissions of Other
Common Anthropogenic Pollutants
The U.S. for 1989 (In Metric Tons)
CO Particulates Hydrocarbons
60,900,000 6,900,000 18,500,000

Why is CO a pollutant? a hazard?

Notes on importance:

Carbon Monoxide (CO) permanently binds with the Fe in Hemoglobin and permanently destroys that group

Particulates contribute to Smog and Lung disorders including cancer, haze, etc.

Hydrocarbons are greenhouse gases, contribute to Smog, are potentially toxic, and contribute to Smog and Lung disorders, haze, etc.

Local or Global Pollution -

Why is particulate pollution usually, local and gaseous pollution usually, global?
Sulfur Dioxide (SO2) Emissions
1989 1980
North & Central Am. 20,700,000 23,900,000
Asia ? 1,263,000
Europe ~23,000,000 ?
USSR 9,318,000 12,800,000

Atmospheric Sources

Primary forms are SO2, H2S, in the gas phase and SO4-2 in the condensed phases. From the burning of sulfur containing fuels. From bacterial reduction of SO4-2 to H2S and sulfur containing proteins. Natural sources are volcanoes which produce large quantities of SO2 and biological processes.

Notes on significance:

SO2 and NO2 (NOx) in the presence of water contribute to acid precipitation (acid rain) and photochemical smog. Acid Rain adversely effects agriculture, forests, aquatic habitats, and the weathering of building materials. SO2 and NO 2aerosols impair visibility.

SO2 concentrations as low as 0.1-0.2 ppm can incapacitate asthma or emphysema patients.

SO2 combines with water to form sulfuric acid H2SO 4

Primary methods of preventing SO2 is removal of "S" compounds prior to combustion of carbon or hydrocarbon "desulfurization" of Coal or Fuel Oil.
Scrubbing (bubble through solution of calcium oxide CaO (lime) forming CaSO4

Nitrogen Dioxide (NO2 )and
Nitrous Oxide (N2O)
1989 1980
North & Central Am. 21,600,000 22,300,000
Asia 1,400,000 ?
Europe ~15,000,000 ?
USSR 4,190,000 ?

Smog and Acid Deposition

Photochemical Smog is the interaction of electromagnetic radiation from the Sun and Primary Pollutants to form photochemical smog.

Sulfate particles are a major cause of haze and smog.

pH of rain is 5.0 to 5.6 due to CO2 and water interaction as previously described, recall carbonate equilibrium.

Average eastern US precipitation is 4.3 with pHs < 3 and 2.5.

What are the consequences of "Acid Rain"?

  • Toxic: It Kills - fish, plants, aquatic and terrestrial, microorganisms
  • Damage to - Soil and Buildings (Limestone, CaCO3), Oxidizes metal and pits finishes like paint and coatings.
  • Shifts Equilibrium in soil leaching Ca, Mg, K, and other cations.
  • Weakens species making them susceptible to disease (AIDS type effect)
  • Stunts growth of crops
  • Proposed to be the third largest cause of lung disease in US after smoking and radon.



Effects may cross borders and thus are exported to other countries.

Indoor Air Pollution

This is the source of one of the most significant pollution exposures facing humans.


Duration of exposure
We spend 70 to 90% of our time indoors.

Intensity of exposure
Levels reach 10 to 40 times those of outdoor air concentrations.

Estimates of 6,000 excess cancer deaths each year (excluding radon) and 20,000 excess cancer deaths from Radon alone.

Industrial exposure is estimated by the author and EPA to be 100,000 to 200,000 premature deaths each year to workers from indoor air in industrial settings.

Specific indoor air problems

  • Radon
  • Asbestos
  • Formaldehyde
  • Smoke
  • Fumes (ever been to a dry-cleaning shop) ("nose analysis")
  • Secondary Smoke
  • Buildup of toxic fumes

Relationships between

  • Vapor pressure
  • Formaldehyde and building materials
  • Particulate matter
  • Building air exchange (Outdoor air "dilution", Why?)

What is the "Sick Building Syndrome"?
Why does it exist?

Effect of Air Pollution on Living Organisms


Cumulative effect of all of these pollutants is:

  • Emphysema
  • Respiratory tract irritation from gas and particles
  • Asthma
  • Heart trouble
  • Lung cancer
  • Irritation


Office of Technology Assessment estimates 50,000 premature deaths in US each year from respiratory or cardiac problems as result of air pollutants

American Lung Association estimates 120,000 US deaths each year from air pollution

EPA estimates air pollution costs $150 billion yearly in health care
$100 billion from indoor air pollution
$40 billion from automobiles


Chronic exposure to ozone, acid rain, sulfur, and nitrogen oxides may be most significant and synergistic.

Damage to leaves, roots, microorganisms (nitrogen fixing bacteria) etc. all weaken plant resistance to insects, frost, fungi, mosses, and disease.

Equilibration shifts in nutrients, aluminum ions, etc.

Aquatic Organisms Are Also At Risk

Acid precipitation is a major threat.

Low buffering capacity permits acid shock.


Hint: What is physiological pH and what does it control?

Aluminum soil leached by acid precipitation kills fish by interfering with gill oxygen exchange

Liming is a temporary fix.

> ~ 75,000 lakes or streams world wide have been acidified to a substantial loss of aquatic life or are stressed.

Air Pollution Control and Clean Air Act of 1977 as revised in 1990

Established national ambient air quality standards (NAAQS) for 7 outdoor pollutants:

  • suspended particulate matter
  • sulfur oxides
  • carbon monoxide
  • nitrogen oxides
  • ozone
  • hydrocarbons
  • lead
    Why is nitrogen oxide unchanged and lead reduced?

Toxic Air Pollutants

A list of 600 toxic air pollutants was proposed

EPA has emission standards of 7 of the 600 toxic air pollutants:

  • arsenic
  • asbestos
  • benzene
  • beryllium
  • mercury
  • vinyl chloride
  • radioactive isotopes
Goals for CFCs, CO2, NOx, Auto emission Standards etc.

Methods of Pollution Control

Control of

Pollutants in general
Sulfur dioxide
Nitrogen oxides
Particulate matter emissions
Motor vehicle emissions
Troposphere ozone
Indoor air pollutants
+ 600 other pollutants (189 prime)


Set limits, provide technology, provide incentive

Conservation of energy use in general and recycling and mass transit

Cleaner (low S fuel) and alternative Fuels and electric motors as alternative (batteries), Nuclear (fission, fusion?)

Modifying industrial plants and the engines for cleaner burning lower operating temperatures for NOx for example or collection devices in conjunction with reduced emission processes

Convert coal to gas first (eliminate particulate and S at same time)

Eliminating SO2 and NOx will reduce O3 in Troposphere from Photochemical reactions

Control Population?

Prevent indoor air pollutant buildup using air-to-air heat exchangers

Materials evaluation prior to use as building materials (indoor +) Methods of Pollution Control

Introduction of CaO (lime) into burning chamber for industrial burning


To form Ca salts with SO4-2 and NO3 -(chemical modification, neutralization & conversion to salts and products {gypsum CaSO4} {CaSO4 and H2O used in plaster and wall board}

Higher smoke stacks to get above the inversion layer reduce local particulate, smog and pollution but let it fall elsewhere

Capture particulate and some pollutants using Electrostatic Precipitators, Baghouse Filters, Cyclone Separators, Wet Scrubbers.

Chemical Modification - example NOx and HCNO (isocyanic acid converts 99% of NOx to N2 and water {not yet technically feasible commercially}.

"Rule of Thumb"
Cleanup vs. Prevention - Prevention is always cheaper in the long run.

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