Air and Air Pollution G. Tyler Miller’s Living in the Environment 13 th Edition Chapter 17 G. Tyler Miller’s Living in the Environment 13 th Edition Chapter 17

INDICATOR SPECIES Lichens are PIONEER ORGANISMS Lichens are a good example of MUTUALISM Lichens are good indicators of air pollution because they: –Are long lived –Are found in almost every ecosystem –Are non-motile –Absorb air

The Atmosphere  Troposphere  weather  Troposphere  weather  Stratosphere  78% N 2, 21% O 2  water vapor  78% N 2, 21% O 2  water vapor  Ozone layer-  removes 95% of UV  Ozone layer-  removes 95% of UV  Greenhouse effect

Altitude (kilometers) Ozone concentration (ppm) Altitude (miles) Stratospheric ozone Stratosphere Troposphere Photochemical ozone Ozone is a pollutant in the troposphere

Natural Sources of Air Pollutants Dust and particulates from windstorms and soil Sulfur oxides and particulates from volcanoes Nitrogen oxides, carbon oxides, and particulates from forest fires Hydrocarbons and pollen from plants Methane and hydrogen sulfide from decaying plants Salts from the sea

Outdoor Air Pollution  Primary pollutants:  Secondary pollutants: emitted directly into the troposphere in a potentially harmful form emitted directly into the troposphere in a potentially harmful form formed in the troposphere from the interaction of primary pollutants with each other or with components of the air formed in the troposphere from the interaction of primary pollutants with each other or with components of the air

Primary Pollutants Secondary Pollutants Sources Natural Stationary COCO 2 SO 2 NONO 2 Most hydrocarbons Most suspended particles SO 3 HNO 3 H 2 SO 4 H2O2H2O2 O3O3 PANs MostandsaltsNO 3 – Mobile SO 4 2 –

Photochemical Smog  Brown-air smog ( brown color due to NO 2 )  Photochemical reaction: a chemical reaction activated by light  Photochemical reaction: a chemical reaction activated by light  Photochemical oxidants: can react with and oxidize certain compounds that are normally not oxidized. Can irritate the respiratory tract and damage crops and trees. (NO 2, O 3, and PAN’s)  Photochemical oxidants: can react with and oxidize certain compounds that are normally not oxidized. Can irritate the respiratory tract and damage crops and trees. (NO 2, O 3, and PAN’s)

Photochemical Smog N 2 + O 2  2NO (colorless gas formed from the combustion of N 2 within an engine or boiler) 2NO + O 2  2NO 2 (noxious yellowish-brown gas formed in the troposphere in the presence of sunlight) 3NO 2 + H 2 O  2HNO 3 (acid rain) + NO NO 2 + UV radiation  NO + O O + O 2  O 3 (in troposphere is a pollutant) Aldehydes and PAN’s (peroxyacyl nitrates) are formed from the interaction of several primary and secondary pollutants

Solar radiation Ultraviolet radiation NO Nitric oxide Photochemical smog H 2 O Water NO 2 Nitrogen dioxide Hydrocarbons O 2 Molecular oxygen HNO 3 Nitric acid PANs Peroxyacyl nitrates Aldehydes (e.g., formaldehyde) O 3 Ozone O Atomic oxygen

Clear day

Smoggy day

Photochemical Smog Worse in afternoon when sun is strongest Worse in warm sunny climates

Nitric oxideNitrogen dioxideOzone A.M.NoonP.M. Time Parts per million

Industrial Smog (burning coal)  Gray-air smog  Industrial smog  Sulfuric acid  Sulfur dioxide  Particulates

Industrial Smog - when burning coal C + O 2  2CO C + O 2  CO 2 S + O 2  SO 2 2SO 2 + O 2  2SO 3 SO 3 + H 2 O  H 2 SO 4 (acid rain) 2NH 3 + H 2 SO 4  (NH 4 ) 2 SO 4 –Ammonium sulfate particles and soot ( C ) give the air its gray color – thus gray air smog

Industrial Smog Is a problem in urban industrialized areas where coal is burned –China –India –Ukraine

Smog Frequency and Severity Depend upon: –Local climate and topography –Population density –Amount of industry –Type of fuels used Precipitation and wind clean the air.

Temperature Inversions Warmer air Inversion layer Cool layer Mountain Valley Decreasing temperature Increasing altitude Polluted air cannot rise and escape MEXICO CITY

Temperature Inversion Inversion layer Mountain range Sea breeze Descending warm air mass Decreasing temperature Increasing altitude Polluted air cannot rise and escape Los Angeles

Regional Outdoor Air Pollution from Acid Deposition Most air pollutant emitters use tall smokestacks to release pollutants above the inversion layer. This reduces local air pollution but increases regional air pollution downwind. ACID DEPOSITION (Acid Rain) – fallout of the acid components from these air contaminants. (pH < 5.6)

Wind Transformation to sulfuric acid (H 2 SO 4 ) and nitric acid (HNO 3 ) Nitric oxide (NO) Acid fog Ocean Sulfur dioxide (SO 2 ) and NO Windborne ammonia gas and particles of cultivated soil partially neutralize acids and form dry sulfate and nitrate salts Dry acid deposition (sulfur dioxide gas and particles of sulfate and nitrate salts) Farm Lakes in deep soil high in limestone are buffered Lakes in shallow soil low in limestone become acidic Wet acid deposition (droplets of H 2 SO 4 and HNO 3 dissolved in rain and snow)

Acid Deposition in the US Fig p. 429

Acid Buffering Soils with calcium carbonate (limestone) (CaCO 3 ) can neutralize (buffer) some acid input. [CaCO 3 + 2H +  Ca 2+ + CO 2 + H 2 O] The areas most sensitive to acid deposition are those containing thin acidic soils and those already damaged from years of exposure to acid rain

Acid Deposition and Humans  Respiratory diseases  Toxic metal leaching: decreased soil pH increases the solubility of certain metal ions in the soil (can result in loss of soil fertility and increase in toxic metals)  Toxic metal leaching: decreased soil pH increases the solubility of certain metal ions in the soil (can result in loss of soil fertility and increase in toxic metals)  Decreased visibility  Damage to structures, especially containing limestone  Decreased productivity and profitability of fisheries, forests, and farms

Acid Deposition and Aquatic Systems  Fish declines  Undesirable species  Aluminum toxicity  Acid shock- from rapid runoff  Acid shock- from rapid runoff

Aluminum Toxicity Lake acidification can result in the solubilizing of aluminum from the surrounding soil and underlying rock. Increased levels of aluminum in the water can stimulate the overproduction of mucus in the gills of certain fish, clogging their gills and asphyxiating them.

Acid Deposition, Plants, and Soil  Nutrient leaching  Heavy metal release  Weakens trees

Emission Acid deposition SO 2 H 2 O 2 PANs NO X O 3 Others Direct damage to leaves and bark Reduced photosynthesis and growth Increased Susceptibility to drought, extreme cold, insects, mosses, and disease organisms Soil acidification Leaching of soil nutrients Acid Release of toxic metal icons Root damage Reduced nutrient and water uptake Tree death

The 1990 amendments to the Clean Air Act have helped to reduce some of the harmful impacts of acid deposition in the United States. However, there is still a long way to go.

PreventionCleanup Reduce air pollution by improving energy efficiency Reduce coal use Increase natural gas use Increase use of renewable resources Burn low-sulfur coal Remove SO 2 particulates, and NO x from smokestack gases Remove No x from motor vehicular exhaust Tax emissions of SO 2 Add lime to neutralize acidified lakes Add phosphate fertilizer to neutralize acidified lakes

Indoor Air Pollution Levels of common pollutants are generally 2 – 5 times higher inside homes and buildings than outside. Levels of particulates can be up to 60% higher indoors than outdoors. Pesticides approved for outdoor use only, were 10 times higher inside than outside monitored homes. Pollution levels inside cars in traffic-clogged areas can be up to 18 times higher than outside the vehicle.

Indoor Air Pollution/Sick Building Syndrome Fig p. 434

Radon  Radon-222  4 picocurie level  Occurs in certain areas based on geology  Associated with uranium and organic material in rock Fig p. 436

Effects of Air Pollution on Living Organisms and Materials  Damage to mucous membranes  Respiratory diseases (see Fig p. 438)  Damage to plant leaves and roots  Reduction in primary productivity  Deterioration of materials (See Table 17-3 p. 440)

Indoor Exposure Developing countries (rural) 67% Developing countries (urban) 23% Developed countries (rural) 1% Total deaths 2.8 million Developed countries (urban) 9% Outdoor Exposure Developing countries (urban) 93% Developed countries (urban) 7% Total deaths 0.2 million

Solutions: Preventing and Reducing Air Pollution  Clean Air Act (1970, 1977, 1990) Federal government established air pollution regulations which are enforced by each state and major city  Clean Air Act (1970, 1977, 1990) Federal government established air pollution regulations which are enforced by each state and major city  National Ambient Air Quality Standards (NAAQS) for CO, NO 2, SO 2, SPM (suspended particulate matter), O 3, and Pb in outdoor air.  Primary standard: set to protect human health  Secondary standards: set to prevent environmental and property damage  Primary standard: set to protect human health  Secondary standards: set to prevent environmental and property damage  Output control vs. input control

Emissions Trading Policy Clean Air Act of 1990 enables the 110 most polluting power plants in 21 states to buy and sell SO 2 pollution rights. A utility that emits less than its limit receives more pollution credits. It can use these to: –Avoid reductions in SO 2 emissions from some of its other facilities –Bank them for future plant expansions –Sell them to other utilities

Emission Reduction

Electrostatic Precipitator Dirty gas Dust discharge Electrodes Cleaned gas

Dirty gas Baghouse Filter Dust discharge Bags

Cyclone Separator Dirty gas Dust discharge Cleaned gas

Dirty gas Dirty water Clean water Wet Scrubber Wet gas Cleaned gas

PreventionCleanup Mass transit Bicycles and walking Less polluting engines Less polluting fuels Improve fuel efficiency Get older, polluting cars off the road Give buyers tax write- offs for buying low- polluting, energy- efficient vehicles Restrict driving in polluted areas Emission control devices Car exhaust Inspections twice a year Stricter emission standards Methods for Reducing Emissions from Motor Vehicles

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