2Origin of Modern Atmosphere original atmosphere surrounded the homogenous planet Earth and probably was composed of H and Hesecond atmosphere evolved from gases from molten EarthH2O, CO2, SO2, CO, S2, Cl2, N2, H2, NH3, and CH4allowed formation of oceans and earliest lifemodern Atmosphereevolved after Cyanobacteria started photosynthesizingoxygen produced did not reach modern levels until about 400 million years ago
3Earth’s Atmospherecompared to the size of the Earth (104 km), the atmosphere is a thin shell (120 km).
5Troposphere 8 to 14.5 kilometers high (5 to 9 miles) most dense the temperature drops from about 17 to - 52 degrees Celsiusalmost all weather is in this region
6Stratosphere extends to 50 kilometers (31 miles) high dry and less densetemperature in this region increases gradually to -3 degrees Celsius, due to the absorption of ultraviolet radiationozone layer absorbs and scatters the solar ultraviolet radiationninety-nine percent of "air" is located in first two layersevery 1000-m 11% less air pressure
7Composition Nitrogen (N2, 78%) Oxygen (O2, 21%) Argon (Ar, 1%) myriad of other very influential components are also present which include the Water (H2O, %), "greenhouse" gases or Ozone (O3, %), Carbon Dioxide (CO2, %),
8Importance of the Atmosphere Physicistsphysical properties and processes that take place between the radiant energy and atmospheric gasesChemistsbehavior of the chemical materials in the atmospherethe ways in which lightning causes the formation of substanceschemistry of the ozone layer and of chemicals introduced from industrial processes
9Astronomers and space scientists the layer through which they must peer before entering the realms of spaceMeteorologists, climatologists and geographerslower layers of the atmospherepredicting the weatherinvestigating climatic regionsexamine the effects of climate and weather on human society
12Major Sources of Primary Pollutants Stationary SourcesCombustion of fuels for power and heat – Power PlantsOther burning such as Wood & crop burning or forest firesIndustrial/ commercial processesSolvents and aerosolsMobile SourcesHighway: cars, trucks, buses and motorcyclesOff-highway: aircraft, boats, locomotives, farm equipment, RVs, construction machinery, and lawn mowers
13Source: http://www.epa.gov/air/oaqps/takingtoxics/p1.html#1 Scientists estimate that millions of tons of toxic pollutants are released into the air each year. Most air toxics originate from manmade sources, including both mobile sources (e.g., cars, buses, trucks) and stationary sources (e.g., factories, refineries, power plants). However, some are released in major amounts from natural sources such as forest fires. Routine emissions from stationary sources constitute almost one-half of all manmade air toxics emissions.
1454 million metric tons from mobile sources in 1990 There are two types of stationary sources that generate routine emissions of air toxics:"Major" sources are defined as sources that emit 10 tons per year of any of the listed toxic air pollutants, or 25 tons per year of a mixture of air toxics. Examples include chemical plants, steel mills, oil refineries, and hazardous waste incinerators. These sources may release air toxics from equipment leaks, when materials are transferred from one location to another, or during discharge through emissions stacks or vents. One key public health concern regarding major sources is the health effects on populations located downwind from them."Area" sources consist of smaller sources, each releasing smaller amounts of toxic pollutants into the air. Area sources are defined as sources that emit less than 10 tons per year of a single air toxic, or less than 25 tons per year of a mixture of air toxics. Examples include neighborhood dry cleaners and gas stations. Though emissions from individual area sources are often relatively small, collectively their emissions can be of concern—particularly where large numbers of sources are located in heavily populated areas.EPA’s published list of "source categories" now contains 175 categories of industrial and sources that emit one or more toxic air pollutants. For each of these source categories, EPA indicated whether the sources are considered to be "major" sources or "area" sources. The 1990 Clean Air Act Amendments direct EPA to set standards requiring all major sources of air toxics (and some area sources that are of particular concern) to significantly reduce their air toxics emissions.
15Human Impact on Atmosphere Burning Fossil FuelsUsing Nitrogen fertilizers and burning fossil fuelsRefining petroleum and burning fossil fuelsManufacturingAdds CO2 and O3 to troposphereGlobal WarmingAltering ClimatesProduces Acid RainReleases NO, NO2, N2O, and NH3 into troposphereProduces acid rainReleases SO2 into troposphereReleases toxic heavy metals (Pb, Cd, and As) into troposphereair/products.html
16Criteria Air Pollutants EPA uses six "criteria pollutants" as indicators of air qualityNitrogen Dioxide: NO2Ozone: ground level O3Carbon monoxide: COLead: PbParticulate Matter: PM10 (PM 2.5)Sulfur Dioxide: SO2Volatile Organic Compounds: (VOCs)EPA established for each concentrations above which adverse effects on health may occur
17Nitrogen Dioxide (NO2)Properties: reddish brown gas, formed as fuel burnt in car, strong oxidizing agent, forms Nitric acid in airEffects: acid rain, lung and heart problems, decreased visibility (yellow haze), suppresses plant growthSources: fossil fuels combustion, power plants, forest fires, volcanoes, bacteria in soilClass: Nitrogen oxides (NOx)EPA Standard: ppm
19Ozone (O3)Properties: colorless, unpleasant odor, major part of photochemical smogEffects: lung irritant, damages plants, rubber, fabric, eyes, 0.1 ppm can lower PSN by 50%,Sources: Created by sunlight acting on NOx and VOC , photocopiers, cars, industry, gas vapors, chemical solvents, incomplete fuel combustion productsClass: photochemical oxidants
20Ozone (O3)10,000 to 15,000 people in US admitted to hospitals each year due to ozone- related illnessChildren more susceptibleAirways narrowerMore time spent outdoors
21Mobile Source Emissions: Hydrocarbons – Precursors to Ozone
22Carbon Monoxide (CO)Properties: colorless, odorless, heavier than air, % of atmosphereEffects: binds tighter to Hb than O2, mental functions and visual acuity, even at low levelsSources: incomplete combustion of fossil fuels % from auto exhaustClass: carbon oxides (CO2, CO)EPA Standard: 9 ppm5.5 billion tons enter atmosphere/year
24Lead (Pb) Properties: grayish metal Effects: accumulates in tissue; affects kidneys, liver and nervous system (children most susceptible); mental retardation; possible carcinogen; 20% of inner city kids have [high]Sources: particulates, smelters, batteriesClass: toxic or heavy metalsEPA Standard: 1.5 ug/m32 million tons enter atmosphere/year
26Mobile Source Emissions: Fine Particulate Matter (PM2.5)
27Sulfur Dioxide (SO2) Properties: colorless gas with irritating odor Effects: produces acid rain (H2SO4), breathing difficulties, eutrophication due to sulfate formation, lichen and moss are indicatorsSources: burning high sulfur coal or oil, smelting or metals, paper manufactureClass: sulfur oxidesEPA Standard: 0.3 ppm (annual mean)Combines with water and NH4 to increase soil fertility
28VOCs (Volatile Organic Compounds) Properties: organic compounds (hydrocarbons) that evaporate easily, usually aromaticEffects: eye and respiratory irritants; carcinogenic; liver, CNS, or kidney damage; damages plants; lowered visibility due to brown haze; global warmingSources: vehicles (largest source), evaporation of solvents or fossil fuels, aerosols, paint thinners, dry cleaningClass: HAPs (Hazardous Air Pollutants)MethaneBenzeneChlorofluorocarbons (CFCs), etc.Concentrations indoors up to 1000x outdoors600 million tons of CFCs
29Other Air Pollutants Carbon dioxide ChloroFluoroCarbons Formaldehyde BenzeneAsbestosManganeseDioxinsCadmiumOthers not yet fully characterized
30Factors that increase and/or decrease pollution Local climate (inversions, air pressure, temperature, humidity)Topography (hills and mountains)Population densityAmount of industryFuels used by population and industry for heating, manufacturing, transportation, powerWeather: rain, snow,windBuildings (slow wind speed)Mass transit usedEconomics
31Thermal Inversion Pollutants • surface heated by sun warmaircool air• surface heated by sun• warm air rises (incl. pollutants)• cools off, mixes with air of equaldensity & disperseswarm air (inversion layer)• surface cools rapidly (night)• a layer of warm air overlays surface• polluted surface air rises but cannotdisperse ⇒ remains trapped
32Smog Forms ...when polluted air is stagnant (weather conditions, geographic location)Los Angeles, CA
33PollutionThe term “Smog” (smoke and fog) was first used in 1905 to describe sulfur dioxide emissionIn 1952, severe pollution took the lives of 5000 people in London“It isn’t pollution that’s harming the environment. It’s the impurities in our air and water that are doing it.” Former U.S. Vice President Dan Quayle97annual.html
35Ultraviolet radiation SolarradiationPhotochemical SmogUltraviolet radiationNONitric oxideOAtomicoxygenO2MolecularoxygenNO2NitrogendioxideH2OWaterHydrocarbonsPANsPeroxyacylnitratesAldehydes(e.g., formaldehyde)O3OzoneHNO3Nitric acidP h o t o c h e m i c a l S m o g
37Why is indoor air quality important? 70 to 90% of time spent indoors, mostly at homeMany significant pollution sources in the home (e.g. gas cookers, paints and glues)Personal exposure to many common pollutants is driven by indoor exposureEspecially important for susceptible groups – e.g. the sick, old and very young
38ExposureTime spent in various environments in US and less-developed countries
39House of Commons Select Committee Enquiry on Indoor Air Pollution (1991) “[There is] evidence that 3 million people have asthma in the UK… and this is increasing by 5% per annum.”“Overall there appears to be a worryingly large number of health problems which could be connected with indoor pollution and which affect very large numbers of the population.”[The Committee recommends that the Government] “develop guidelines and codes of practice for indoor air quality in buildings which specifically identify exposure limits for an extended list of pollutants…”
40Sources of Indoor Air Pollutants Building materialsFurnitureFurnishings and fabricsGluesCleaning productsOther consumer productsCombustion appliances (cookers and heaters)Open firesTobacco smokingCookingHouse dust mites, bacteria and mouldsOutdoor air
41Important Indoor Air pollutants Nitrogen dioxideCarbon monoxideFormaldehydeVolatile Organic Compounds (VOCs)House dust mites (and other allergens, e.g. from pets)Environmental tobacco smokeFine particlesChlorinated organic compounds (e.g. pesticides)Asbestos and man-made mineral fibresRadon
42Health Effects Nitrogen dioxide Respiratory irritant Elevated risk of respiratory illness in children, perhaps resulting from increased susceptibility to respiratory infection; inconsistent evidence for effects in adultsConcentrations in kitchens can readily exceed WHO and EPA standards
43Health Effects Carbon monoxide An asphyxiant and toxicant Hazard of acute intoxication, mostly from malfunctioning fuel-burning appliances and inadequate or blocked fluesPossibility of chronic effects of long-term exposure to non- lethal concentrations, particularly amongst susceptible groups
44Health Effects Formaldehyde Sensory and respiratory irritant and sensitizerPossible increased risk of asthma and chronic bronchitis in children at higher exposure levelsIndividual differences in sensory and other transient responsesCaution over rising indoor concentrations
45Health Effects Volatile Organic Compounds (VOCs) Occur in complex and variable mixturesMain health effects relate to comfort and well- being, but benzene (and other VOCs) are carcinogenicConcern about possible role of VOCs in the aetiology of multiple chemical sensitivity; also implicated in sick building syndrome
46Health Effects House dust mites House dust mites produce Der p1 allergen, a potent sensitizerGood evidence of increased risk of sensitization with increasing allergen exposure, but this does not necessarily lead to asthmaSmall reductions in exposure will not necessarily lead to reduced incidence and/or symptomsIndoor humidity is important
47Health Effects Fungi and bacteria Dampness and mould-growth linked to self- reported respiratory conditions, but little convincing evidence for association between measured airborne fungi and respiratory diseaseInsufficient data to relate exposure to (non- pathogenic) bacteria to health effects in the indoor environment
48Health Effects Environmental tobacco smoke (ETS) Sudden infant death syndromeLower respiratory tract illnessMiddle ear diseaseAsthma12 million children exposed to secondhand smoke in homes
49Health Effects Fine particles Consistent evidence that exposure to small airborne particles (e.g. PM10) in ambient air can impact on human health; mechanisms uncertainChronic Obstructive Pulmonary Disease and Cardiovascular Disease patients and asthmatics probably at extra riskRelative importance of indoor sources is unknown
50Health Effects Radon Can cause lung cancer Estimated that 7,000 to 30,000 Americans die each year from radon-induced lung cancerOnly smoking causes more lung cancer deathsSmokers more at risk than non-smokers
51Radon Risk: Non-Smoker Radon Level(pCI/L)If 1000 people who did not smoke were exposed to this level over a lifetime.. About X would get lung cancerThis risk of cancer from radon exposure compares to …What to do:208Being killed in a violent crimeFix your home104310x risk of dying in a plane crash2Risk of drowning<1Risk of dying in a home fire1.3Average indoor radon level0.4If you are a former smoker, your risk may be higher
52Radon Risk: Smoker If you are a former smoker, your risk may be lower Radon Level(pCI/L)If 1000 people who smoke were exposed to this level over a lifetime.. About X would get lung cancerThis risk of cancer from radon exposure compares to …What to do:Stop smoking and …20135100x risk of drowningFix your home1071100x risk of dying in a home fire857429100x risk of dying in a plane crash2152x the risk of dying in a car crash1.39Average indoor radon level0.43If you are a former smoker, your risk may be lower
53Radon 55% of our exposure to radiation comes from radon colorless, tasteless, odorless gasformed from the decay of uraniumfound in nearly all soilslevels vary
54(From: http://www.epa.gov/iaq/radon/zonemap.html) Zone pCi/L>4<2
55Radon: How it Enters Buildings Cracks in solid floorsConstruction jointsCracks in wallsGaps in suspended floorsGaps around service pipesCavities inside wallsThe water supply
56Radon: Reducing the Risks Sealing cracks in floors and wallsSimple systems using pipes and fansMore information: echSuch systems are called "sub-slab depressurization," and do not require major changes to your home. These systems remove radon gas from below the concrete floor and the foundation before it can enter the home. Similar systems can also be installed in houses with crawl spaces.
57Sick Building Syndrome (SBS) Building Related Illness (BRI) vsBuilding Related Illness (BRI)
58Sick Building Syndrome A persistent set of symptoms in > 20% populationCauses(s) not known or recognizableComplaints/Symptoms relieved after exiting building
59Complaints/Symptoms Headaches Dry Skin Fatigue Nasal Congestion Reduced MentationIrritabilityEye, nose or throat irritationDry SkinNasal CongestionDifficulty BreathingNose BleedsNausea
60Building Related Illness Clinically Recognized DiseaseExposure to indoor air pollutantsRecognizable Causes
63Movement of Air Into / Out of Homes Amount of air available to dilute pollutantsimportant indicator of the likely contaminant concentrationIndoor air can mix with outside air by three mechanismsinfiltrationnatural ventilationforced ventilation
64Movement of Air Into / Out of Homes Infiltrationnatural air exchange that occurs between a building and its environment when the doors and windows are closedleakage through holes or openings in the building envelopepressure induceddue to pressure differentials inside and outside of the buildingespecially important with cracks and other openings in wall
65Movement of Air Into / Out of Homes InfiltrationTemperature induced (stack effect)driven by air movement through holes in floors, ceilingsin winter, warm air in a building wants to rise, exits through cracks in ceiling and draws in
66Movement of Air Into / Out of Homes Natural ventilationair exchange that occurs when windows or doors are opened to increase air circulationForced ventilationmechanical air handling systems used to induce air exchange using fans and blowersTrade-offscut infiltration to decrease heating and cooling costs vs. indoor air quality problems
67Movement of Air Into / Out of Homes Infiltration ratesInfluenced byhow fast wind is blowing, pressure differentialstemperature differential between inside and outside of houselocation of leaks in building envelope
69The Clean Air Act Congress found: • Most people now live in urban areas• Growth results in air pollution• Air pollution endangers living thingsIt decided:• Prevention and control at the source was appropriate• Such efforts are the responsibility of states and local authorities• Federal funds and leadership are essential for the development of effective programsThe Clean Air Act
70Clean Air Act Originally signed 1963 States controlled standards1970 – Uniform Standards by Federal Govt.Criteria PollutantsPrimary – Human health riskSecondary – Protect materials, crops, climate, visibility, personal comfort
71Clean Air Act 1990 version 1997 version Acid rain, urban smog, toxic air pollutants, ozone depletion, marketing pollution rights, VOC’s1997 versionReduced ambient ozone levelsCost $15 billion/year -> save 15,000 livesReduce bronchitis cases by 60,000 per yearReduce hospital respiratory admission 9000/year
72Clean Air ActPresident George W. Bush signed rules amending Clean Air Act that allowed power plants and other industries to increase pollution significantly without adopting control measures
73Clean Air Act http://www.epa.gov/air/oaq_caa.html Title I - Air Pollution Prevention and ControlPart A - Air Quality and Emission LimitationsPart B - Ozone Protection (replaced by Title VI)Part C - Prevention of Significant Deterioration of Air QualityPart D - Plan Requirements for Nonattainment AreasTitle II - Emission Standards for Moving SourcesPart A - Motor Vehicle Emission and Fuel StandardsPart B - Aircraft Emission StandardsPart C - Clean Fuel VehiclesTitle III - GeneralTitle IV - Acid Deposition ControlTitle V - PermitsTitle VI - Stratospheric Ozone Protection
74Specific Air Pollution Treatment Technology TraditionalMove factory to remote locationBuild taller smokestack so wind blows pollution elsewhereNewBiofiltration : vapors pumped through soil where microbes degradeHigh-energy destruction: high-voltage electricityMembrane separation: diffusion of organic vapors through membraneOxidation: High temperature combustor
82Sulfur Dioxide Control Advanced Flue Gas Desulfurization Demonstration Project|Objective: To reduce SO2 emissions by 95% or more at approximately one-half the cost of conventional scrubbing technology, significantly reduce space requirements, and create no new waste streams.Technology/Project Description: Pure Air built a single SO2 absorber for a 528-MWe power plant. Although the largest capacity absorber module of its time in the United States, space requirements were modest because no spare or backup absorber modules were required. The absorber performed three functions in a single vessel: prequenching, absorbing, and oxidation of sludge to gypsum. Additionally, the absorber was of a co-current design, in which the flue gas and scrubbing slurry move in the same direction and at a relatively high velocity compared to that in conventional scrubbers. These features all combined to yield a state-of-the-art SO2 absorber that was more compact and less expensive than contemporary conventional scrubbers.Other technical features included the injection of pulverized limestone directly into the absorber, a device called an air rotary sparger located within the base of the absorber, and a novel wastewater evaporation system. The air rotary sparger combined the functions of agitation and air distribution into one piece of equipment to facilitate the oxidation of calcium sulfite to gypsum.Pure Air also demonstrated a unique gypsum agglomeration process, PowerChip®, to significantly enhance handling characteristics of adsorbed flue gas desulfurization AFGD-derived gypsum.
84Source: NATIONAL AIR POLLUTANT EMISSION TRENDS, United States Environmental Protection Agency Office of Air Quality Planning and Standards EPA-454/RMarch 2000
85Comparison of 1970 and 1999 Emissions Source: Latest Findings on National Air Quality: 1999 Status and Trends EPA EPA-454/FSince the 1970 Clean Air Act was signed into law, emissions of each of the sixpollutants decreased, with the exception of NOx . Between 1970 and 1999,emissions of NOx increased 17 percent. The majority of this increase can beattributed to heavy-duty diesel vehicles and coal-fired power plants. EPA hasmajor initiatives to reduce emissions of NOx considerably from these sources.Emissions of NOx contribute to the formation of ground-level ozone (smog),acid rain, and other environmental problems, even after being carried by thewind hundreds of miles from their original source.
87Between 1970 and 1999, U.S. population increased 33 percent, vehicle miles traveled increased 140 percent, and gross domestic product increased 147 percent. At the same time, total emissions of the six principal air pollutants decreased 31 percent.
88EPA tracks trends in air quality based on actual measurements of pollutant concentrations in the ambient (outside) air at monitoringsites across the country. Monitoring stations are operated by state,tribal, and local government agencies as well as some federalagencies, including EPA. Trends are derived by averaging directmeasurements from these monitoring stations on a yearly basis. Thechart at above shows that the air quality based on concentrations ofthe principal pollutants has improved nationally over the last 20years (1980–1999). The most notable improvements are seen for Pb,CO, and SO2 with 94-, 57- and 50-percent reductions, respectively.
89Number of People Living in Counties with Air Quality Concentrations Above the Level of the National Ambient Air Quality Standards (NAAQS) in 1999Despite great progress in air quality improvement, approximately 62 million people nationwide still lived in counties with pollution levels above the national air quality standards in This number does not take into consideration the 8-hour ozone standard.Blue bars represent 8-hour standard for ozone.
90Trends in Sulfur Dioxide Emissions Following Implementation of Phase I of the Acid Rain Program: Total State-level Utility SO2 (1980, 1990, 1999)This set of maps illustrates the geographic and temporal trends in state-level utility sulfur dioxide (SO2) emissions before and during implementation of Phase I of the Acid Rain Program. The maps illustrate total state-level utility SO2 emissions in 1980, 1990, and 1999.Total sulfur dioxide emissions were significantly reduced during Phase I of the Acid Rain Program. In the first five years of the program, Phase I sources reduced SO2 emissions by more than 50% from 1980 levels; total utility SO2 emissions (Phase I and II sources) were reduced almost 30% nationwide. Although most SO2 emissions occur in the Midwestern U.S., it is important to note that over time, this same region has also seen the most significant decrease in SO2 emissions in the country. The highest SO2 emitting states in 1980 (Ohio, Indiana, and Pennsylvania), have achieved an average reduction of about 40%, from 1980 levels.Acid rain causes acidification of lakes and streams and contributes to damage of trees at high elevations (for example, red spruce trees above 2,000 feet) and many sensitive forest soils. In addition, acid rain accelerates the decay of building materials and paints, including irreplaceable buildings, statues,and sculptures that are part of our nation's cultural heritage. Prior to falling to the earth, SO2 and NOx gases and their particulate matter derivatives, sulfates and nitrates, contribute to visibility degradation and harm public health.
91Fifty Years of Air Pollution Figures are in millions of metric tons per year
92Mobile Sources: The Last Ten Years VOCs CO NOx PM10 SOx LeadMobile Sources: The Last Ten Years-3%-8%-10%-24%-29%Percent reductions shown are based on estimates of tons/year from mobile sources over the time period-85%
93Who is Affected by Air Pollution? 63Over 74 million people are subjected to high levels of at least one of these pollutantsWho is Affected by Air Pollution?2219951Ozone CO NO PM10 SO2 LeadMillions of people living in counties with air quality that exceeds each NAAQS (1990 data)
94Milestones in the Control of Automotive Emissions Autos linked to air pollutionOriginal CAA, PCV valvesHC & CO exhaust controlsCAA amendments, EPA formedEvaporative controlsFirst I/M ProgramNOx exhaust controlsFirst catalytic convertersNew cars meet statutory limitsVolatility limits on gasolineNew CAA AmendmentsMilestones in the Control of Automotive Emissions
951987 Montreal Protocol: CFC emissions should be reduced by 50% by the year 2000 (they had been increasing 3% per year.)1990 London amendments: production of CFCs, CCl4, and halons should cease entirely by 2000.1992 Copenhagen agreements: phase- out accelerated to 1996.
96Goals of Kyoto Protocol Reduction of greenhouse gases to below levels:5.2% world wide reduction on average by6% for Canada byWhen sufficient countries ratify the Protocol (at least 55 countries comprising at least 55% of emissions), Protocol comes into effectUSA - 25% of emissions