Urban Air Quality Urban Air Quality Gaseous Composition

Urban Air Quality

Urban Air Quality • Gaseous Composition of the Atmosphere

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

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

Urban Air Quality • Types of Urban Air Pollutants – Examples of Primary Pollutants • Carbon monoxide (CO) • Carbon dioxide (CO 2) • Sulfur dioxide (SO 2) • Nitric oxide (NO) • Hydrocarbons (HCs) • Suspended Particulate Matter (SPMs)

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

Urban Air Quality • Types of Urban Air Pollutants – Examples of Secondary Pollutants • Nitrogen Dioxide (NO 2) • Sulfur Trioxide (SO 3) • Nitric Acid (HNO 3) • Hydrogen Peroxide (H 2 O 2) • Tropospheric Ozone (O 3) • Nitrate (NO 3) • Peroxyacetyl Nitrates (PANs)

Urban Air Quality • Chemical Classes of Urban Air Pollutants – Carbon Oxides • CO 2 – Sulfur Oxides • SO 2

Urban Air Quality • Chemical Classes of Urban Air Pollutants – Nitrogen Oxides • NO (nitric oxide) • NO 2 (nitrogen dioxide) • N 2 O (nitrous oxide - “laughing gas!”) – Sulfur Oxides • SO 2 (sulfur dioxide) • SO 3 (sulfur trioxide)

Urban Air Quality • Chemical Classes of Urban Air Pollutants – Volatile Organic Compounds (VOCs) • CH 4 (methane) • C 6 H 6 (benzene) • CFCs (chlorofluorohydrocarbons) • CH 20 (formaldehydr)

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

Urban Air Quality • Chemical Classes of Urban Air Pollutants – Photochemical Oxidants • O 3 (tropospheric ozone) • H 2 O 2 (hydrogen peroxide) • PANs (peroxyacetylnitrates)

Urban Air Quality • Chemical Classes of Urban Air Pollutants – Radioactive Substances • Rn 222 (Radon) – Toxic Metals • Pb - Lead • Cd - Cadmium • Hg - Mercury • Ar - Arsenic

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)

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

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

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

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

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

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

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

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

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

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

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

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

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

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.

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

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

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

Urban Air Quality • Acid Deposition – Components • Primary Pollutants – Nitrogen Oxides (NOx) – Sulfur Oxides (SOx) Secondary Pollutants – Nitric Acid (HNO 3) – Sulfuric Acid (H 2 SO 4)

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

Urban Air Quality • Acid Deposition – Mechanisms of Acid Deposition • Dry Deposition • Precipitation

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

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

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

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

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

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

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!)

Urban Air Quality • Acid Deposition – Environmental Impacts of Acid Deposition • Terrestrial Ecosystems – Most damage when p. H < 5. 1 – Damage to tree foliage bathed in acidic fog

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

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

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

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

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

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

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

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