SWES 210 Exam 3Atmospheric Science and Air Pollution- What is air made of?o Permanent gases – remain  78% N2 which cannot be taken up 21% O2 Trace amounts of Ne, He, H2, Xe, Ar (permanent gases)o Variable gases – vary in concentration  CO2 ~.038% Trace amounts of O3, CH4, N2O, H2O- Atmosphere’s layers (atmosphere is the thin layer of gases thatsurrounds earth)o Troposphere – 0-10 km Air is responsible for weather Air gets colder/less dense as elevation increases Contains ¾ of the atmosphere’s mass because air isdensero Stratosphere – 10-~50 km 1,000 times drier and less dense Little vertical mixing Where the good ozone is (absorbs UV radiation that would reach the surface)o Mesosphere - ~50-85 km Very low air pressure and temperatureo Thermosphere – 85-120 km- Atmosphere propertieso Atmospheric pressure – force per unit area produced by acolumn that decreases with altitudeo Relative humidity – ratio of water vapor a given volume ofair contains to max amount it could contain at a giventemperature- Weather and climateo Front – boundary between air masses that differ intemperature and moisture (therefore density) Warm – where a warmer, moister mass replaces acolder one Cold – colder drier air mass replaces a warmer one- Convective circulation o Less dense warm air rises and creates vertical currentso As air rises into regions of lower atmospheric pressure, itexpands and coolso As the cool air descends, it becomes denser and replaces the warm, rising air- Thermal inversions: layer in which temperature increases with height, can lead to smog being trapped close to the ground- Wind systemso Hadley cells – pair of convective cells that are activated by solar radiation  Warm air rises and expands, releasing moisture Air moves northward and southward  Cools and descends at 30 degrees N and So Coriolis effect – earth rotates on its axis so that it spins faster on the poles that results deflecting them from a straight path All this equals curving global wind patterns- Outdoor air pollutiono Air pollutants Gases and particulate materials added to the atmosphere Can affect climate and/or harm people or other organismso Volcanoes (natural source) Aerosols- Sulfur dioxide, H2O, O2 all react and condense into fine droplets - Reflect sunlight back to space- Cool off earth’s surfaceo Fires (natural source) – may build up from human suppression and as a result promotes destructive forest fireso Dust storms (natural source) – from windo Human caused Primary – emitted directly from source (burning of fossil fuels) in a form that can cause harm or react to form bad substances Secondary – form in atmosphere when primary pollutants react with components in the atmosphere- Ozone and other oxidants in smog- Legislation o Air Pollution Control Act (1963) funded research and encouraged emission standardso Clean Air Act (1970) Set standards for air quality, limits on emissions Provided funds for pollution control research Allowed citizens to sue parties violating the standardso Clean Air Act (1990) strengthened regulations for auto emissions, toxic air pollutants, acidic deposition, stratospheric ozone depletion- Emissions and air quality standardso EPA sets nationwide standards for emission and concentrations of ambient pollutantso States monitor air quality Develop, implement and enforce regulations Submit plans to EPA EPA takes over enforcement if plans are adequateo Criteria pollutants – ambient pollutants that pose great threats on people CO – produced by incomplete combustion of fuel- Bad because it can bind to hemoglobin, preventing it from binding with O2 SO2 – produced by combustion of coal- Can form other harmful molecules that result in acid deposition NO2 – contributes to smog and acid deposition- Form nitrogen oxides  Tropospheric ozone – results from interaction of sun, heat, nitrogen dioxides and volatile carbon- Causes respiratory problems Particulate matter – solid or liquid particles small enough to be suspended in the atmosphere- Dust and soot that can damage respiratory tissues Lead – heavy metal released from combustion of leaded gas- Accumulates within body tissues and cause nervous system malfunction- Smog o Industrial: seen in larger cities on the east coast, burning of coal and oil  creates sulfuric acid, ammonium sulfate, carbon monoxideo Photochemical: exhaust from cars, N2  nitric oxide  ozone or acid rain Formed in hot, sunny cities, surrounded by mountains Light driven reactions between primary pollutants and atmospheric compounds- Ways to reduce smogo Catalytic converters on cars o Financial incentives to replace aging vehicleso Vehicle inspectiono Reduce sulfur in diesel- Areas that fail National Ambient Air Standards are typically big cities- US emissionso 63% CO, 13% NOx, volatile organic compounds 13%, 9% SO2o Average US driver emits 6 tons of CO2/year + otherso Total emissions have declined 60% since the Clean Air Act of 1970  Despite increased population, energy consumption, miles traveled, gross domestic product Scrubbers – chemically convert or remove airborne pollutants before emitted from smokestacks- Hazardous air pollutants (toxic)o Substances that cause cancer, reproductive effects, organ problemso EPA regulates 188 toxic air pollutants from metal smelting, sewage, industry  heavy metals, VOCs, dieselo CAA regulations reduced more than 35% since 1990 - Air pollution in Chinao Gov’t is trying to reduce  Shutting down factories and installing pollution control devices Encouraging clean fuels, renewable and nuclear energyo Asian Brown Cloud – 2 miles thick layer of pollution of Southern Asia- Stratospheric ozone depletiono Depleting chemicals  hydrocarbons like CFCs (don’t react, stay in stratosphere for a century) Chemicals used in fridges, aerosols, fire extinguisher, ethane and methane Releases chlorine atoms that split ozone (one can destroy 100,000 ozone molecules- Cl+O3  ClO + O2o N2O (nitrous oxide)  produced by bacteria in N-fertilized soil, in stratosphere forms NO, also reacts with ozoneo Antarctic ozone hole  high altitude polar stratospheric clouds form during winter that contain condensed nitric acid that splits chlorine atoms off chlorine containing substances Chlorine atoms becomes trapped in clouds over Antarctica In spring when the