Air Pollution                                                                                                         

Sources of Pollution Point Sources Non-Point Sources Primary Pollutants Secondary Pollutants Natural Sources Larger than anthropogenic sources

Thermal Inversions Warm air on top of a layer of cool air near surface Prevents pollutants from rising & dispersing

Major Categories of Air Pollutants: Regulated by the Clean Air Act Carbon Monoxide Nitrogen Oxides Sulfur Oxides Ozone Lead Suspended Particulate Matter Volatile Organic Compounds

Carbon Monoxide Source: burning fossil fuels Replaces oxygen in blood stream Bonds to hemoglobin Only dangerous in high concentrations

Nitrogen Oxides: Photochemical Smog Source: Automobiles (burning gasoline) NO2 + UV  O3 + Nitrates Yellow-brown color, sweet smell

Sulfur Oxides: Industrial Smog Source: Coal-fired industry, electric SO2 + UV  O3 + Sulfates Gray-air smog, colored by soot

Sulfur & Nitrogen Oxides: Acid Rain Source: Coal-fired industry, electric Normal Rain pH 5.6 CO2 + H2O  H2CO3 (normal) NO2 + H2O  HNO3 (contributes) SO2 + H2O  H2SO4 (strong acid) Secondary pollutant Limestone acts as a buffer: neutralize acid

Effects of Acid Deposition Human respiratory illness Leach toxic metals from pipes to water Damage building materials Lakes – acid shock Release Al3+ into water – asphyxiate fish Dissolve nutrients - reduce algal growth Plants and soils Weakens trees, competition with mosses Acids leach minerals from soil

Ground-level Ozone Source: burning fossil fuels Secondary Pollutant! Formed from rxns with UV Health Effects Chest pain, coughing, throat irritation, congestion Worsen respiratory disease (bronchitis, asthma, etc.) Environmental Damage Damage leaves, reduce crop yields

Lead Source: industry, waste incinerators Regulations removed lead from gasoline Toxicant, accumulates in bones Neurological, kidney, immune and reproductive systems

Particulate Matter Source: dust, fires, volcanoes, fossil fuels Regulated PM10 and PM2.5 Smaller than 10 um (thickness of one hair strand) Health effects Lung irritation, reduced visibility, altered nutrient balance, damage to crops

Reducing Pollution Carbon Monoxide Nitrogen Oxides Sulfur Oxides Ozone CO detectors in homes Nitrogen Oxides Catalytic converters and regulations on vehicles Sulfur Oxides Scrubbers on smokestacks Ozone Lead Unleaded gasoline, removed from paints Particulates Spray mines and construction with water

Clean Air Act 1970, ammended 1977 & 1990 Comprehensive regulations on 6 common air pollutants: CO, NOx, SOx, O3, PM10, lead Addressed acid rain, toxic emissions, ozone depletion, automobile exhausts Created NAAQS (National Ambient Air Quality Standards) Gave enforcement authority: mainly controlled and enforced by state governments

Air Quality Index