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Understanding Urban Air Quality: Sources and Regulation

Explore the gaseous composition of the atmosphere in urban areas, types of pollutants, their sources, and regulatory standards to protect public health and the environment. Learn about primary and secondary pollutants, chemical classes like carbon oxides and VOCs, and the impacts and control measures for pollutants like SPMs and lead. Discover the importance of National Ambient Air Quality Standards (NAAQS) and the Clean Air Acts in managing urban air pollution effectively.

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Understanding Urban Air Quality: Sources and Regulation

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  1. Urban Air Quality

  2. Urban Air Quality • Gaseous Composition of the Atmosphere

  3. Urban Air Quality • Sources of Urban Air Pollutants • Stationary Sources • Mobile Sources • Non-Point (Area)

  4. Urban Air Quality • Types of Urban Air Pollutants • Primary Pollutant - a pollutant that directly enters the air as a result of natural events or human activities

  5. Urban Air Quality • Types of Urban Air Pollutants • Examples of Primary Pollutants • Carbon monoxide (CO) • Carbon dioxide (CO2) • Sulfur dioxide (SO2) • Nitric oxide (NO) • Hydrocarbons (HCs) • Suspended Particulate Matter (SPMs)

  6. Urban Air Quality • Types of Urban Air Pollutants • Secondary Pollutant - a pollutant that is formed in the air through chemical reactions between or among primary pollutants or between primary pollutants and other gases in the atmosphere

  7. Urban Air Quality • Types of Urban Air Pollutants • Examples of Secondary Pollutants • Nitrogen Dioxide (NO2) • Sulfur Trioxide (SO3) • Nitric Acid (HNO3) • Hydrogen Peroxide (H2O2) • Tropospheric Ozone (O3) • Nitrate (NO3) • Peroxyacetyl Nitrates (PANs)

  8. Urban Air Quality • Chemical Classes of Urban Air Pollutants • Carbon Oxides • CO • CO2 • Sulfur Oxides • SO • SO2

  9. Urban Air Quality • Chemical Classes of Urban Air Pollutants • Nitrogen Oxides • NO (nitric oxide) • NO2 (nitrogen dioxide) • N2O (nitrous oxide - “laughing gas!”) • Sulfur Oxides • SO2 (sulfur dioxide) • SO3 (sulfur trioxide)

  10. Urban Air Quality • Chemical Classes of Urban Air Pollutants • Volatile Organic Compounds (VOCs) • CH4 (methane) • C6H6 (benzene) • CFCs (chlorofluorohydrocarbons) • CH20 (formaldehydr)

  11. Urban Air Quality • Chemical Classes of Urban Air Pollutants • Suspended Particulate Matter (SPMs) • Dust • Soot • Asbestos • Pollen

  12. Urban Air Quality • Chemical Classes of Urban Air Pollutants • Photochemical Oxidants • O3 (tropospheric ozone) • H2O2 (hydrogen peroxide) • PANs (peroxyacetylnitrates)

  13. Urban Air Quality • Chemical Classes of Urban Air Pollutants • Radioactive Substances • Rn222 (Radon) • Toxic Metals • Pb - Lead • Cd - Cadmium • Hg - Mercury • Ar - Arsenic

  14. Urban Air Quality • Regulation of Urban Air Pollution • Clean Air Acts • Passed in 1970, 1977, 1990 • Enacted federal air pollution regulations that are enforced by each state • Established National Ambient Air Quality Standards (NAAQS)

  15. Urban Air Quality • Regulation of Urban Aair Pollution • NAAQS • 7 Criteria Pollutants • SPMs • Sulfur Oxides • Carbon Monoxide • Nitrogen Oxides • Tropospheric Ozone • VOCs • Lead

  16. Urban Air Quality • Regulation of Urban Aair Pollution • NAAQS • Primary NAAQS - standards established to protect human health • Secondary NAAQS - standards established to protect all organisms • Nonattainment Area - any area that does not meet primary or secondary NAAQS for a criteria pollutant

  17. Urban Air Quality National Ambient Air Quality Standards Carbon Monoxide 9 ppm over 8-hr period, not to be exceeded more than once a year; 35-ppm for 1-hr period Ozone 0.12 ppm for 1-hr period, not to be exceeded more than once per year

  18. Urban Air Quality National Ambient Air Quality Standards Sulfur Dioxide 0.03 ppm annual average; 0.14 ppm for 24-hr period, not to be exceeded more than once per year Nitrogen Oxides 0.05 ppm annual average

  19. Urban Air Quality • Regulation of Urban Air Pollution • Criteria Pollutants • Tropospheric Ozone • Source: Chemical reactions between VOCs, nitrogen oxides, and sunlight • Health Effects: Reduced lung function; asthma; congestion • Environmental Impacts: Reduced visibility; plant damage, reduced photosynthesis and nutrient uptake, crop destruction; forest diebacks • Property Damage: Rubber; plastics

  20. Urban Air Quality • Regulation of Urban Air Pollution • Criteria Pollutants • Carbon Monoxide • Source: Incomplete combustion of fossil fuels • Health Effects: Reduced oxygen levels; impaired visual perception; reduced lung function; asthma; congestion • Environmental Impacts: Reduced visibility; plant damage • Property Damage: Rubber; plastics

  21. Urban Air Quality • Regulation of Urban Air Pollution • Criteria Pollutants • Nitrogen and Sulfur Oxides • Source: Incomplete combustion of fossil fuels • Health Effects: Lung damage; respiratory illnesses • Environmental Impacts: Acid deposition; plant damage; photochemical smog; crop destruction • Property Damage: Enhanced chemical weathering

  22. Urban Air Quality • Regulation of Urban Air Pollution • Criteria Pollutants • SPMs • Source: Incomplete combustion of fossil fuels; agriculture; unpaved roads • Health Effects: Lung damage; respiratory illnesses • Environmental Impacts: Reduced visibility (haze • Property Damage: Discoloration of clothing and structures

  23. Urban Air Quality • Regulation of Urban Air Pollution • Criteria Pollutants • Lead • Source: Leaded gasoline; lead paint; smelters; lead-acid batteries • Health Effects: Damage to nervous system; cancer; mental retardation; digestive disorders • Environmental Impacts: Harmful to wildlife

  24. Urban Air Quality • Photochemical (Brown-Air) Smog • A mixture of primary and secondary pollutants (mostly tropospheric ozone) formed under the influence of sunlight

  25. Urban Air Quality • Photochemical (Brown Air) Smog • Factors of Formation • Topography • Local climate • Population density • Amount of industry • Industrial fuel types

  26. Urban Air Quality • Photochemical (Brown Air) Smog • Factors of Formation • Topography • Hills and mountains reduce air flow in valleys and allow pollutant levels to build up at ground level • Buildings in cities slow wind speed, reducing dilution and dispersal of pollutants

  27. Urban Air Quality • Photochemical (Brown Air) Smog • Factors of Formation • Topography • Thermal Inversion • Sunny climate • Light winds • Mountains on three sides, ocean on the other • High population density • High motor vehicle usage • High industrialization using fossil fuels

  28. Urban Air Quality • Photochemical (Brown Air) Smog • Factors of Formation • Topography • Los Angeles Basin • Hemmed in by mountains on 3 sides and ocean on the other • 14 million people; 23 million motor vehicles • Frequent thermal inversions • Air pollution capital of U.S.

  29. Urban Air Quality • Photochemical (Brown Air) Smog • Factors of Formation • Local Climate • Areas with high average annual precipitation and wind speeds have less smog due to dilution and dispersal

  30. Urban Air Quality • Industrial (Gray-Air) Smog • Mixture of sulfur dioxide, suspended droplets of sulfuric acid, and SPMs • Found mostly in LDCs where coal and heavy oils are burned • China • Ukraine • Eastern Europe

  31. Urban Air Quality • Acid Deposition • The falling of acids and acid-forming compounds from the atmosphere to the Earth’s surface

  32. Urban Air Quality • Acid Deposition • Components • Primary Pollutants • Nitrogen Oxides (NOx) • Sulfur Oxides (SOx) Secondary Pollutants • Nitric Acid (HNO3) • Sulfuric Acid (H2SO4)

  33. Urban Air Quality • Acid Deposition • Acid Sources • Coal-burning power plants • Smelters • Factors • Urban areas

  34. Urban Air Quality • Acid Deposition • Mechanisms of Acid Deposition • Dry Deposition • Precipitation

  35. Urban Air Quality • Acid Deposition • Environmental Impacts of Acid Deposition • Regional environmental problem because acids remain in atmosphere for only a few days • Environmental impacts depend on buffering capacity of soils

  36. Urban Air Quality • Acid Deposition • Environmental Impacts of Acid Deposition • Ecosystems most harmed by acid deposition are those with thin soils that lack natural buffering

  37. Urban Air Quality • Acid Deposition • Environmental Impacts of Acid Deposition • Damage to materials • Statues • Buildings • Metals • Car finishes

  38. Urban Air Quality • Acid Deposition • Environmental Impacts of Acid Deposition • Human Health • Bronchitis • Asthma

  39. Urban Air Quality • Acid Deposition • Environmental Impacts of Acid Deposition • Aquatic Ecosystems • Acid Shock • Aluminum toxicity • Stimulates excessive mucus formation leading to asphyxiation of fish by clogging their gills

  40. Urban Air Quality • Acid Deposition • Environmental Impacts of Acid Deposition • Aquatic Ecosystems • Formation of methylmercury • Highly toxic • Soluble in fatty tissue of animals • Bioaccumulation

  41. Urban Air Quality • Acid Deposition • Environmental Impacts of Acid Deposition • Aquatic Ecosystems • Fun Facts • 16,000 lakes in Norway and Sweden contain no fish • 9,000 lakes in U.S. are threatened with excess acidity (most in the Great Lakes!)

  42. Urban Air Quality • Acid Deposition • Environmental Impacts of Acid Deposition • Terrestrial Ecosystems • Most damage when pH < 5.1 • Damage to tree foliage bathed in acidic fog

  43. Urban Air Quality • Acid Deposition • Environmental Impacts of Acid Deposition • Terrestrial Ecosystems • Increased susceptibility to various stressors • Cold temperatures • Diseases • Insects • Drought • Depletion of plant nutrients

  44. Urban Air Quality • Urban Climate • Cities are generally warmer, rainier, foggier, and cloudier than suburbs or rural areas

  45. Urban Air Quality • Urban Climate • Cities generate enormous amounts of heat • Automobiles • Factories • Furnaces • Lights • Air conditioners • People

  46. Urban Air Quality • Urban Climate • Urban Heat Island - the buildup of heat in the atmosphere above an urban area

  47. Urban Air Quality • Indoor Air Pollution • Sources • Combustion • Building materials and furnishings • Household cleaning products • Personal care products • Central heating/cooling systems • Outside sources - radon gas and pesticides • Poor ventilation

  48. Urban Air Quality • Indoor Air Pollution • Most Dangerous Indoor Air Pollutants • Formaldehyde • Asbestos • Cigarette smoke • Radon-222 • Fiberglass

  49. Urban Air Quality • Indoor Air Pollution • Leading cause of cancer • High-risk health problem for humans • “Sick Building Syndrome” • Coughing • Sneezing • Nausea • Burning eyes • Flulike symptoms

  50. Urban Air Quality • Indoor Air Pollution • “Sick Building Syndrome” • 17% of all buildings in U.S. are “sick”, including the U.S. EPA headquarters in Washington, DC • Mineral fibers falling from ceiling tiles are main culprit

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