Air Pollution

Chapter 18-19Air PollutionThere is no place on Earth that isnt affected by air pollution

Air pollution: presence of chemicals in the atmosphere in concentrations high enough to harm organisms, ecosystems, human-made materials or to alter climateRanges from annoying to lethalRefers to pollution in the troposphere

Natural sourcesDust, wildfires, volcanic eruptions

Human sourcesIndustrialized and urban areas fossil fuel burningPrimary Pollutants: chemicals or substances emitted directly into the air from natural sources and human activitiesCarbon monoxide, carbon dioxide, sulfur dioxide and nitric oxides; particulate matter; VOCs (natural sourcesterpenes, plant fragrance)

Secondary Pollutants: primary pollutants react with one another and natural components to form harmful chemicals, often in the presence of sunlight and waterOzone, acid deposition (sulfates and nitrates)

To determine and monitor Air Quality, the EPA actively monitorscarbon monoxideozoneleadnitrogen dioxideparticulate matter (also known as particle pollution)sulfur dioxide

Major Air PollutantsCarbon OxidesCarbon Dioxide: from fossil fuel burning (major pollutant); is a greenhouse gas that impacts climate; required for photosynthesis; colorless and odorless

Carbon Monoxide: from combustion of carbon (exhaust, forest burning, fossil fuels, tobacco smoke); Limits oxygen binding in hemoglobin which can result in heart attack, asthma, emphysema, nausea and death; colorless and odorlessdangerous indoor air pollutantNitrogen Oxides (NOx) and Nitric Acid

Nitric Oxide (NO): combustion in cars, coal burning, lightning, part of soil and water (nitrogen cycle); colorless and odorless

Nitrogen Dioxide (NO2): nitrogen monoxide reacts with oxygen (NO2); reacts with water to form nitric acid and nitrate salts (acid deposition); forms photochemical smog (with sunlight); helps in the formation of tropospheric ozone; stinky, reddish-brown gas

Nitrous Oxide (N2O): greenhouse gas from fertilizers and animal wastes, also fossil fuel burning

** all are irritants to eyes, nose and throat, aggravate asthma and bronchitis; suppress plant growth and harm aquatic lifeSulfur Dioxide and Sulfuric Acid

Sulfur Dioxide (SO2): 1/3 comes from natural sources (sulfur cycle), the rest is anthropogenic (coal burning, oil refining, smelting); corrosive gas

Sulfuric Acid: forms when SO2 reacts with water in the atmosphere, then falls as acid deposition (acid rain).

**Aggravate breathing problems (respiratory irritant), decrease plant growth, corrosiveParticulates

Suspended particulate matter (solid particles and liquid droplets); particles smaller than 10 micrometers are regulated by the EPA as air pollution (not filtered by nose/throat)

Outdoor: dust, wildfires, sea salt, coal/oil burning, cars (especially diesel), construction; road dust, rock crushing; volcanic activity

Indoor: cigarettes, burning inside (developing countries)

**Aggravate eyes, nose, and throat, damage lungs, asthma/bronchitis, genetic mutations, and cancer (premature death)

**Reduces the amount of incoming solar radiation (weather)

Ozone (O3)

Secondary pollutant that contributes to photochemical smogTropospheric ozone bad. Stratospheric ozone good.

Ozone thinning is the stratospherewhich increases the amount of UV radiation that reaches usDamages living tissueResults from release of CFCs and other Freonsfrom coolants and aerosols

Montreal ProtocolLimit these chemicals in manufactured products

**Coughing and breathing problems (asthma and emphysema), lung/heart disease, irritant; damaging to rubber and plastic

Volatile Organic Compounds (VOCs)

Organic compounds (hydrocarbons) that exist as gases in the atmosphereGive off strong aroma (paint, perfume, gasoline, flatulence)

Help in formation of smog, not all hazardousbut some have the potential to be harmful

Ex. Methanegreenhouse gas from landfills, cows, decomposition, oil and gas burning/refiningOthers include benzene, industrial solvents, gas and plasticsMercury: found in coal and oil, released from fossil fuel burning, can settle out into water. Seeing bioaccumulation into food chains.Toxin for central nervous system

Lead: occurs naturally in rocks and soils, also present in fuels and paints.Toxic to central nervous system (children), affects learning, concentration, and intelligence

Factors Affecting Air PollutionIncrease air pollutionBuildings break up windHills/mountains decrease air flowHigh temperature increases reactions Emissions of VOCs increase smog formationTemperature inversions (warm air over cool)

Decrease air pollutionHeavy particles settle out of airRain/snow cleanse airSalty sea spray washes airWinds mix airPollutants removed by reactions

Acid DepositionAir pollutants mix with water in air to form acidic precipitation (acid rain)Nitrogen and sulfur oxidesform nitric and sulfuric acid (pH ~5)Has been occurring since the Industrial RevolutionUsually a regional problemdownwind of coal burning facilitiesPollutants are moved by winds

Damages statues, buildings; causes respiratory diseases, leach toxic metals into the environment from rocks; harmful to aquatic ecosystems, hurts agriculture, and weakens forests and plants

Reduced by limiting emissions of pollutants (alternative energy sources)SmogIndustrialUnhealthy mix of sulfur dioxide and sulfuric acid and solid particlesComes from coal burning in large quantitiesRarely a problem in developed countriesbig problem in developing (China)Sulfur dioxide and sulfates mostly; grey smog

PhotochemicalMixture of primary and secondary pollutants formed under the influence of UV radiationbrown smogmade up mostly of ozone

Indoor vs. Outdoor Air PollutionIndoor Air Pollution from burning wood, charcoal in open fires or poorly designed stoves; cigarette smokeCarbon monoxide and particulatesImpacts high poverty/poor countries

Sources include:Tobacco smoke formaldehydeRadon gasFine particulatesPesticide residuesLeadOrganic solventsLiving organisms (mites, roaches)Mold and fungal sporesRadon GasColorless, odorless radioactive gas that is produced by the radioactive decay of uranium-238 (from underground rock)Only problematic in certain areas of the country

Can seep through cracks in the foundation and build up to harmful levels in air, or seep into groundwater

Damages lung tissue and lead to cancer (second leading cause of lung cancer)Radon-222 decays to Polonium-210 (harmful/carcinogen)

Dealing with Air PollutionClean Air Act: set aside air pollution regulationsEPA monitors pollutants and sets standards for emissionsEPA's mission is to protect human health and the environment. To achieve this mission, EPA implements a variety of programs under the Clean Air Act that focus on:reducing outdoor, or ambient, concentrations of air pollutants that cause smog, haze, acid rain, and other problems;reducing emissions of toxic air pollutants that are known to, or are suspected of, causing cancer or other serious health effects; andphasing out production and use of chemicals that destroy stratospheric ozone.These pollutants come from stationary sources (like chemical plants, gas stations, and powerplants) and mobile sources (like cars, trucks, and planes).

Buy and sell pollution allotments

Prevention in best solution!Improve fuel efficiency standardsAlternative energy sourcesEducate public about pollutionAir Quality IndexNational Ambient Air Quality StandardsEPA sets standards for pollutants harmful to humans or the environment (clean air act)

Primary standards protect public healthSecondary standards protect public welfare

Carbon Monoxide, Lead, Particulates, Ozone, Nitrogen Dioxide and Sulfur Dioxide