2 What Is the Nature of the Atmosphere? The atmosphere is structured in layers, including the troposphere, which supports life, and the stratosphere, which contains the protective ozone layer.
3 Troposphere – “Weather Breeder” - 75–80% of the earth’s air mass- Closet to the earth's surface- Chemical composition of air-Rising and falling air currents: weather and climate-Involved in chemical cycling
4 The Stratosphere Is Our Global Sunscreen Similar composition to the troposphere, with 2 exceptionsMuch less waterO3, ozone layer, filters UVLocation – 11 – 30 miles up
5 What is Air Pollution and What Are the Major Outdoor Pollution Problems? Air pollution – presence of chemicals in the atmosphere high enough to harm organisms, ecosystems or materials & to alter climateNatural sourcesDust blown by windPollutants from wildfiresand volcanoesVolatile organics releasedby plantsWithdrawing groundwaterHuman (Anthropogenic) sources:mostly in industrialized and/or urban areasStationary sources – examples include industry and power plantsMobile sources – examples include motor vehicles
6 Some Pollutants in the Atmosphere Combine to Form Other Pollutants Primary pollutants – released directly into atmosphereSecondary pollutants – formed by chemical reactions in air
7 What Are the Major Outdoor Air Pollutants? Carbon oxidesCarbon monoxide (CO)Carbon dioxide (CO2)Sources - incomplete combustion of carbon-containing materialsHuman health and environmental impactCO reduces ability of blood to transport O2CO2 Do you need to ask? ;-)Primary Pollutant
8 What Are the Major Outdoor Air Pollutants? Nitrogen oxides (NO) and nitric acid (HNO3)Sources – automobile engines & coal burning power plantsHuman health and environmental impact – greenhouse gas, acid deposition, irritation to eyes, nose, aggravated asthma, etcPhotochemical smog (makes harmful O3) – more laterSulfur dioxide (SO2) and sulfuric acid (H2SO4)Sources – coal burning power plants & smeltingHuman health and environmental impact – acid deposition
9 What Are the Major Outdoor Air Pollutants? ParticulatesSuspended particulate matter (SPM)Sources – natural sources, plowed fields, construction, unpaved roads, tobacco smoke, coal burning power plants, carsHuman health and environmental impact –Irritate nose, throat, aggravate asthma, some can accumulate in body (lead, PCB’s)
10 What Are the Major Outdoor Air Pollutants? Ozone (O3)Sources - photochemical smogHuman and environmental impact – same as others, also damages plants, rubber in tires, etc.Volatile organic compounds (VOCs)Hydrocarbons, terpenes, methaneSources – natural sources, landfills, solvents, rice paddies, natural gas wells, etc.Human and environmental impact – greenhouse gas (CH4), damage plants, can cause cancer
11 Burning Coal Produces Industrial Smog Chemical composition of industrial smog (grey)Reduction of this smog in urban cities of the United StatesChina and smogHuman deaths
12 Sunlight Plus Cars Equals Photochemical Smog Chemical compositionSourcesVOCs + NO2 + Heat +Sunlight yields Ground level O3 and other photochemical oxidantsAldehydesOther secondary pollutantsHuman health and environmental impact
13 A Model of How Pollutants That Make Up Photochemicals Are Formed
14 Several Factors Can Decrease or Increase Outdoor Air Pollution Outdoor air pollution may be decreased bySettling of particles due to gravityRain and snowSalty sea spray from the oceanWindsChemical reactionsOutdoor air pollution may be increased byUrban buildingsHills and mountainsHigh temperaturesEmissions of VOCs from certain trees and plantsGrasshopper effectTemperature inversions
16 What Is Acid Deposition and Why Is It a Problem? Acid deposition is caused mainly by coal-burning power plant and motor vehicle emissions, and in some regions, threatens human health, aquatic life and ecosystems, forests, and human-built structures.
17 Acid Disposition Is a Serious Regional Air Pollution Problem Acid deposition, acid rainFormationLocal versus regional problemsEffects of prevailing windsBuffersWhere is the worst acid deposition?
18 Natural Capital Degradation: Acid Deposition, Acid Rain
19 Current and Possible Future Acid Rain Problem Areas
20 Acid Deposition Has a Number of Harmful Effects Human respiratory disordersAquatic ecosystems affectedRelease of toxic metalsLeaching of soil nutrientsLoss of crops and treesDamage to buildings, statues, and monuments
21 Solutions: Acid Deposition, Prevention and Cleanup
22 What Are the Major Indoor Air Pollution Problems? The most threatening indoor air pollutants are smoke and soot from wood and coal cooking fires (a hazard found mostly in developing countries) and chemicals used in building materials and products.Developing countriesIndoor burningPoor suffer the greatest riskDeveloped countriesIndoor air pollution is greater than outdoor air pollution!!! WHY????
23 Indoor Air Pollution Is a Serious Problem You asked WHY????....11 of the common air pollutants higher inside than outsideGreater in vehicles than outsideHealth risks magnified: people spend 70–98% of their time is indoorsWho are at greatest risk from indoor air pollution?Children under 5 and the elderlySickPregnant womenPeople with respiratory disorders or heart problemsSmokersFactory workers
24 Indoor Air Pollution Is a Serious Problem Four most dangerous indoor air pollutantsTobacco smokeFormaldehydeRadioactive radon-222 gasVery small particlesSources of these pollutantsHuman health risks
25 Indoor Air Pollution Is a Serious Problem Other possible indoor air pollutantsPesticide residuePb particlesLiving organisms and their excrementsE.g., Dust mites and cockroach droppingsAirborne spores of molds and mildewsSick-building syndrome – Let’s watch TWC - SICK BUILDINGS!
26 Science: Sources and Paths of Entry for Indoor Radon-222 Gas
27 What Are the Health Effects of Air Pollution? Air pollution can contribute to asthma, chronic bronchitis, emphysema, lung cancer, heart attack, and stroke.
28 Your Body’s Natural Defenses against Air Pollution Can Be Overwhelmed Respiratory system protection from air pollutantsRole of cilia, mucus, sneezing, and coughingEffect of smoking and prolonged air pollution exposureChronic bronchitisEmphysema
29 Normal Human Lungs and the Lungs of a Person Who Died of Emphysema
30 Air Pollution Is a Big Killer 3 Million deaths per year world-wideMostly in AsiaMain causesEPA: proposed stricter emission standards for diesel-powered vehiclesLink between international trade and air pollutionCargo ships and pollution
31 Premature Deaths from Air Pollution in the U.S.
32 How Should We Deal with Air Pollution? Legal, economic, and technological tools can help to clean up air pollution, but much greater emphasis should be focused on preventing air pollution. - SOUND FAMILIAR???
33 Laws and Regulations Can Reduce Outdoor Air Pollution United StatesClean Air Acts: 1970, 1977, and 1990EPANational ambient air quality standards (NAAQs) for 6 outdoor criteria pollutantsNational emission standards for 188 hazardous air pollutants (HAPs)Toxic Release Inventory (TRI)
34 Laws and Regulations Can Reduce Outdoor Air Pollution Good news in U.S.Decrease in emissionsUse of low-sulfur diesel fuelCuts pollutionDeveloping countriesMore air pollution
35 We Can Use the Marketplace to Reduce Outdoor Air Pollution Emission trading or cap-and-trade programMixed reactions to programSO2 emissions down significantlyNO2 will be tried in the future