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30 Cards in this Set
- Front
- Back
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What’sin ‘Clean’ Air |
•78 %Nitrogen •21 %Oxygen •0.9 %Argon •0.03%Carbon dioxide(300 ppm) •Plustrace gases including methane, hydrogen, nitrous oxide, ozone |
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What is Air Pollution? 1) general term 2) mixture of... |
•Airpollution is a general term referring to a scenario when the air containsgases, aerosols, or vapors in harmful amounts.–‘Harmful’amounts to human health or comfort, animal welfare, or plants and materials •Airpollution is a complex mixture of multiple airpollutants |
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Pollutionof Natural Origin |
Wildfires Volcanoes Vegetation - VOCs,pollens Dusts Seaspray |
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Pollutionfrom Human Activities |
•AKA“Anthropogenic” •Burningof fossil fuels –Electricitygeneration –Heating,cooking –Manufacturing –Transportation •Also,biomass burning, dusts from driving on unpaved roads, use of chemicals |
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PollutantDefinitions •Gas •Aerosol •Vapor |
•Gas – matter that has no fixed volume orshape; it conforms to the volume and shape of its container• •Aerosol – an assemblage of solid or liquidparticles dispersed in a gaseous medium •Vapor – Gaseous state of any substance thatnormally exits as a liquid or solid |
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PollutantDefinitions •Primary pollutant Secondary pollutant |
•Primary pollutant –Directly emitted from the source Secondarypollutant– Formed in the atmosphere through physical and chemical conversion ofprecursors |
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SpecificPollutants of Concern ParticulateMatter 1) definition 2) Sources 3) Defined based on Size. - PM10 - PM10-2.5 - PM 2.5 - PM2.5xx - ~45microns |
1) •Solidor liquid particles suspended in air (an aerosol) –Unitsas mass per unit volume of air: mg/m3 or mg/m3 –Diversechemical composition (dusts, sulfates, metals,organic chemcials, etc.)depending on source –Primaryor secondary 2) •:Fossil fuel combustion (power plants, traffic), industrial activity,wood-burning stoves, and natural sources (dusts, pollen), conversion ofprecursors (NOx, SOx,VOCs) 3) - Particulatematter - Coarseparticulate matter - Fineparticulate matter - Ultrafineparticulate matter - Totalsuspended particles |
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Particular Matter Relationship between diameter and sources 2.5 - 10 0.1 to < 2.5 < 0.1 (ultrafine) |
1) natural and mechanical sources 2) combustion 3) combustion (esp. diesel fuel |
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NitrogenOxides (NOx) 1) Def. ; description; primary? secondary? 2) Sources 3) Contribute to... 4) conversion to ______ contributes to _______ |
1)•Categoryof highly reactive gases including NO2 andNO –NO2 is a brownish gas –Primaryand secondary pollutants 2) •Combustion,primarily fossil fuels–Traffic,power plants, industries 3) •secondaryparticulate matter and ozone formation 4)•Conversionto nitric acid contributesto acid deposition (AKA ‘acid rain’) |
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SulfurDioxide (SO2) 1) Def. ; description; 2) Sources 3) conversion to ______ contributes to _______ |
1) Gaseouspollutant 2) Sources:Combustion of coal & metal ores, also crude oil –Powerplants, trains, ships, metal-processing facilities, industrial boilers –Also,natural source is volcanoes 3) a) SO2 => sulfates & sulfuricacid => ‘acid rain’ b) SO2=> sulfate aerosols=> secondary PM |
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Ozone(O3) 1) description 2) primary or secondary? - formed through... - key component of ... -- levels are... |
1) Colorlessgas–Troposphericozone or ‘ground-level’ ozone–EPA:“Good up high – bad nearby” 2) Secondarypollutant – complex reactions involving NOx& VOCs in presence of sunlight – ‘photochemical smog’ –highly diurnal and seasonal |
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CarbonMonoxide (CO) 1) description 2) Source 3) Specific effect - oxygen? |
1) Colorless,odorless gas 2) Source:Incomplete combustion –Gasoline,natural gas, oil, coal, wood, tobacco, other organic materials –Trafficis the largest contributor to outdoor air 3) Specificeffect – Chemical affinity for hemoglobin –Displacesoxygen in blood –Reducedoxygen delivery |
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Lead 1) Source 2) Levels decrease dramatically when... |
1) Leaded gasoline (historically in US) –Alsometal processing, lead smelters, waste incineration, lead batteries 2)introduction of catalytic converter engine& switch to unleaded gasoline (1975) –Residuallead contamination in soil |
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Mercury 1) source 2) Human exposure pathway (interactions with... - heat? - precipitation? - bacteria converts it to - then it gets into... -- humans... |
1) Commoncomponent of coal 2) - vaporizes - settles out - converted by bacteria from elemental form to organic compound, methylmercury - mostly in sediments of oceans, lakes, river --> methylmercury gets into aquatic food chain and biomagnifies (highest concentrations in large predator fish) - humans exposed largely by fish consumption |
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VolatileOrganic Compounds (VOCs) 1) sources 2) e.g. 3) primary? secondary? |
1) –Oil& gasoline combustion: Somenaturallypresent in oil; others added to gasoline –Industrialuse of solvents, glues –Naturalsources – primarily vegetation 2) E.g.,benzene, formaldehyde, terpenes 3) Primaryand secondary |
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Factorsthat Affect Local and Global Concentrations of Air Pollutants Fateand Transport of Air Pollutants 1) Vary....depending on |
1) Vary temporally(seasonally or daily) and spatially,depending on: –Emissions(amount, source, and patterns) –Weather(temperature, wind speed & direction, precipitation) –Topography –Otherpollutants (chemistry) |
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AtmosphericRegions •Troposphere |
–Earth’ssurface to ~6 miles –Temperaturedecreases with height –Airwell-mixed –Weatherphenomena occur here –Providesthe natural greenhouse effect |
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AtmosphericRegions Stratosphere |
-- From troposphere to ~30 miles --Temperature increases with altitude -- Slow mixing -- Ozone layer provides protection from UV radiation |
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LocalConditions Affecting Transport of Pollutants |
1) Localtropospheric conditions –Normal:surface air, warmed by earth, rises; cooler, denser air above sinks; thuscontinuous mixing and low pollutant concentrations –Temperatureinversion: cooler surface air trapped below warmer air above; thus littlemixing and high pollutant concentrations at ground level 2) Localwindsprovide horizontal mixing |
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ExtremeAir Pollution Episodes The“London Fog” Episode 1)when, what 2)source |
1) December5-9, 1952 - Pollutionso thick – nearly no visibility 2) Primarysource of pollution was coal burning for home heating –Abnormallycold winter –Temperatureinversion led to stagnant air conditions –Pollutionmostly consisted of SO2 and PM |
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The“London Fog” Episode results 1) number of deaths? who did it affect mostly? 2) health effects 3) what regulations did it lead to? |
1) 10,000-12,000 deaths (over severalmonths); Affectedprimarily infants and those over age 45 2) Pneumomia, respiratory conditions, CVD 3) Ledto regulation: USAir Pollution Control Act in 1955 UKClean Air Act in 1956 |
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AirPollution Regulationin the U.S. CleanAir Act (Enacted 1963;Amended 1965, 1967, 1970, 1977, 1990) 1970 Clean Air Act Amendments? (7) - government? -Agencies? - Standards? - states? |
1) –Expansionof federal authority for air pollution control –Creationof U.S. EPA –NationalAmbient Air Quality Standards (NAAQS) for Criteria Air Pollutants –NationalEmission Standards for Hazardous Air Pollutants (NESHAP) –Emissionsstandards for new or modified sources –Newauto emissions standards –Statesto enforce Clean Air Act with an approved state implementation plan (SIP) |
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CriteriaPollutants 1) defined by___ 2) Deemed a general risk to .... 3) regulated by... |
1) •CleanAir Act 2) •humanhealth and/or welfare (includescrops, livestock, property, air & ground transportation, views) 3)•USEPA using National Ambient Air Quality Standards (NAAQS) |
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HazardousAir Pollutants (HAPs) 1) established by _____amendments 2) AKA 3) Includes how many pollutants -are they all hazardous? 4) Ambient standards? 5) regulated through? |
1) 1970Clean Air Act 2)airtoxics 3) >180pollutants including VOCs, mercury compounds, pesticides, solvents,radionuclides –Notall known to be hazardous 4) •neitherappropriate nor practical 5) •emissioncontrols (performance-based standards or technology requirements) |
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RegulatoryApproaches •Ambient standards |
– Set a maximum allowed concentration in ambient air and assess compliance |
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Emissions standards |
– limit the amount of a pollutant that can be emitted from a specific source ----–Specific types of industries -----–Vehicles |
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Technology requirements |
– Enforcement of techniques that must be used to limit emissions ----------–Best available control technology / maximum achievable control technology |
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Market-based regulatory approaches |
–Cap and trade |
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Information requirements |
–Toxics Release Inventory |
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CleanAir Act – More Recent History 1) •1997and 1990 Clean Air Act Amendments largely to address ________ 2) 2007Supreme Court decision |
1) shortcomings: –NAAQSnot met for at least one criteria pollutant in every major urban area in US –Otherissues including HAPs & acid rain 2) •CO2 falls within broad definition of an ‘airpollutant’ under the Clean Air Act, and EPA must regulate it unless it made adetermination that CO2 doesn’t contribute to global climatechange |
