Air Pollution. Sources of Pollution Point Sources Non-Point Sources Primary Pollutants Secondary...
Transcript of Air Pollution. Sources of Pollution Point Sources Non-Point Sources Primary Pollutants Secondary...
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
– 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