Air Pollution Chapter 15

Key Concepts Structure and composition of the atmosphere Types and origins of major outdoor air pollutants Two types of smog Acid deposition and how it can be reduced Harmful effects of air pollutants Preventing and controlling air pollution

When is a Lichen Like a Canary? Mine canaries Lichens Detectors of air pollution Isle Royale in Lake Superior Chernobyl Fig. 15-1, p. 345

When is a Lichen Like a Canary? Fig. 15-1, p. 345

Earth’s Atmosphere Troposphere 78% N2, 21% O2 Stratosphere Ozone layer Fig. 15-2, p. 347

Atmospheric pressure (millibars) Altitude (kilometers) Earth’s Atmosphere Atmospheric pressure (millibars) 200 400 600 800 1,000 120 75 Temperature 110 Pressure 65 100 Thermosphere 90 Mesopause 55 Heating via ozone 80 Mesosphere 45 70 60 Stratopause Altitude (kilometers) Altitude (miles) 35 50 Stratosphere 40 25 30 Tropopause 15 Ozone “layer” 20 Heating from the earth 10 5 Troposphere –80 –40 40 80 120 Pressure = 1,000 millibars at ground level (Sea Level) Temperature (˚C) Fig. 15-2, p. 347

Outdoor Air Pollution What is air pollution? Stationary and mobile sources Primary pollutants Secondary pollutants How air pollutants migrate Health threats Major air pollutants (Table 15-1, p. 349) Volatile organic compounds (VOCs) Carbon dioxide: a pollutant?

Sources and Types of Air Pollutants Primary Pollutants CO CO2 Secondary Pollutants SO2 NO NO2 SO3 Most hydrocarbons HNO3 H2SO4 Most suspended particles H2O2 O3 PANs SO4 2 – Most NO3 – and salts Sources Natural Stationary Mobile Fig. 15-3, p. 348

Table 15-1, p. 349

Photochemical Smog Photochemical reactions Photochemical smog Natural and human origins Brown-air smog Temperature effects Urban areas

Photochemical Smog in Mexico City Fig. 15-4, p. 351

Industrial Smog Science Spotlight, p. 350: Air Pollution in the Past: The Bad Old Days Composition of industrial smog (sulfur dioxide and sulfuric acid) Gray-air smog Situation better in developed countries Serious problem in industrializing countries, such as China “Black Triangle” of eastern Europe Asian brown cloud

Industrial Smog in India Fig. 15-5, p. 351

How Natural Eliminates Smog Rain and snow Salty sea spray Winds

Factors Influencing the Formation of Smog Urban buildings Topography High temperatures “Grasshopper Effect” Temperature inversions

Acid Deposition Sulfur dioxide and nitrogen oxides Wet and dry acid deposition Acid rain Regional air pollution Ohio Valley Buffers Wind transportation

Acid Deposition Fig. 15-6, p. 353 Wind Transformation to sulfuric acid (H2SO4) and nitric acid (HNO3) Windborne ammonia gas and particles of cultivated soil partially neutralize acids and form dry sulfate and nitrate salts Wet acid deposition (droplets of H2SO4 and HNO3 dissolved in rain and snow) Nitric oxide (NO) Dry acid deposition (sulfur dioxide gas and particles of sulfate and nitrate salts) Sulfur dioxide (SO2) and NO Acid fog Farm Lakes in shallow soil low in limestone become acidic Ocean Lakes in deep soil high in limestone are buffered Fig. 15-6, p. 353

pH Measurements at US Sites Fig. 15-7, p. 354

Current and Potential Problems with Acid Deposition Potential problem areas because of sensitive soils Potential problem areas because of air pollution: emissions leading to acid deposition Current problem areas (including lakes and rivers) Fig. 15-8, p. 355

Harmful Effects of Acid Deposition Respiratory diseases in humans (bronchitis and asthma) Leaches metals from water pipes Damages statues and other property Decreases atmospheric visibility (Grand Canyon) Kills fish and other aquatic organisms Leaches plant nutrients from soils Weakens trees (mountaintop forests)

Impacts of Air Pollution on Trees and Water Emission Acid deposition SO2 H2O2 PANs NOX O3 Others Increased Susceptibility to drought, extreme cold, insects, mosses, and disease organisms Direct damage to leaves and bark Reduced photosynthesis and growth Soil acidification Tree death Leaching of soil nutrients Release of toxic metal icons Root damage Reduced nutrient and water uptake Acid Groundwater Fig. 15-9, p. 356

Tree Damage from Acid Deposition Fig. 15-10, p. 356

Reducing Acid Deposition © 2006 Brooks/Cole - Thomson Solutions Acid Deposition Prevention Cleanup Reduce air pollution by improving energy efficiency Add lime to neutralize acidified lakes Reduce coal use Add phosphate fertilizer to neutralize acidified lakes Increase natural gas use Increase use of renewable resources Burn low-sulfur coal Remove SO2 particulates, and Nox from smokestack gases Remove Nox from motor vehicular exhaust Tax emissions of SO2 Fig. 15-11, p. 357

Indoor Air Pollution Pollutants often at higher concentrations indoors Pollution inside cars Most people spent most of their time indoors Cancer risks Sick-building syndrome Mold and allergies Serious problem in developing countries

Major Indoor Air Pollutants Tobacco smoke Formaldehyde Radon Very fine particles

Major Indoor Air Pollutants Para-dichlorobenzene Chloroform Tetrachloro-ethylene Formaldehyde 1, 1, 1- Trichloroethane Styrene Nitrogen Oxides Benzo-a-pyrene Particulates Tobacco Smoke Radon-222 Asbestos Carbon Monoxide Methylene Chloride Fig. 15-12, p. 358

Radon Radioactive Rn-222 Lung cancer threat With uranium in rocks and soils Testing homes Remedies Fig. 15-13, p. 359

Harmful Effects of Air Pollution Human respiratory system Asthma Lung cancer Chronic bronchitis Emphysema Health effects of major air pollutants (Table 15-1, p. 349) Premature deaths Serious threat of indoor air pollution Impact of coal-fired power plants Cancer from diesel exhausts

Human Respiratory System Fig. 15-14a, p. 360

Healthy and Diseased Human Lungs Fig. 15-15, p. 360

Premature US Deaths from Air Pollution Fig. 15-16, p. 361

Preventing and Reducing Air Pollution U.S. Clean Air Acts National Ambient Air Quality Standards Criteria from risk assessments Primary standards Secondary standards Hazardous air pollutants Toxic Release Inventory “Right to Know” laws Emissions trading

Solutions: Stationary Source Air Pollution © 2006 Brooks/Cole - Thomson Solutions Stationery Source Air Pollution Prevention Dispersion or Cleanup Burn low-sulfur coal Disperse emissions above thermal inversion layer with tall smokestacks Remove sulfur from coal Remove pollutants after combustion Convert coal to a liquid or gaseous fuel Tax each unit of pollution produced Shift to less polluting fuels Fig. 15-17, p. 363

Solutions: Motor Vehicles © 2006 Brooks/Cole - Thomson Solutions Motor Vehicle Pollutions Prevention Cleanup Mass transit Emission control devices Bicycles and walking Less polluting engines Less polluting fuels Car exhaust Inspections twice a year Improve fuel efficiency Get older, polluting cars off the road Give buyers tax write- offs for buying low- polluting, energy- efficient vehicles Stricter emission standards Restrict driving in polluted areas Fig. 15-18, p. 364

Solutions: Indoor Air Pollution © 2006 Brooks/Cole - Thomson Solutions Indoor Air Pollution Prevention Cleanup Cover ceiling tiles and lining of AC ducts to prevent release of mineral fibers Use adjustable fresh air vents for work spaces Ban smoking or limit it to well-ventilated areas Increase intake of outside air Change air more frequently Set stricter formaldehyde emissions standards for carpet, furniture, and building materials Circulate building’s air through rooftop greenhouses Prevent radon infiltration Use exhaust hoods for stoves and appliances burning natural gas Use office machines in well-ventilated areas Use less polluting substitutes for harmful cleaning agents, paints, and other products Install efficient chimneys for wood-burning stoves Fig. 15-19, p. 364

Solutions: Air Pollution Prevention Cleanup Improve energy efficiency to reduce fossil fuel use Reduce poverty Distribute cheap and efficient cookstoves to poor families in developing countries Rely more on lower-polluting natural gas Rely more on renewable energy (especially solar cells, wind, and solar-produced hydrogen) Reduce or ban indoor smoking Develop simple and cheap test for indoor pollutants such as particulates, radon, and formaldehyde Transfer technologies for latest energy efficiency, renewable energy, and pollution prevention to developing countries. Fig. 15-20, p. 365

What Can You Do? © 2006 Brooks/Cole - Thomson What Can You Do? Indoor Air Pollution Test for radon and formaldehyde inside your home and take corrective measures as needed. Do not buy furniture and other products containing formaldehyde. Remove your shoes before entering your house to reduce inputs of dust, lead, and pesticides. Test your house or workplace for asbestos fiber levels and for any crumbling asbestos materials if it was built before 1980. Don't live in a pre-1980 house without having its indoor air tested for asbestos and lead. Do not store gasoline, solvents, or other volatile hazardous chemicals inside a home or attached garage. If you smoke, do it outside or in a closed room vented to the outside. Make sure that wood-burning stoves, fireplaces, and kerosene- and gas-burning heaters are properly installed, vented, and maintained. Install carbon monoxide detectors in all sleeping areas. Fig. 15-21, p. 365