Atmospheric Photochemistry And Air Pollution IV

12.335/12.835 EXPERIMENTAL ATMOSPHERIC CHEMISTRY, FALL 2014TOPIC 1ATMOSPHERIC PHOTOCHEMISTRY andAIR POLLUTIONAIR POLLUTION: HUMAN HEALTH,REGULATION, MONITORING & COSTSRONALD PRINN & MARIA ZAWADOWICZOCTOBER 2, 20141

INCORPORATING METEOROLOGY IN THE BOX MODEL1. USE THE u MEASUREMENTS TO ALIGN THE MODEL x AXIS AND USE IN THEBOX MODEL ADVECTION TERMS.2. USE THE T & u MEASUREMENTS TO CALCULATE A RICHARDSON NUMBER TOHELP CHOOSE SUITABLE texchange VALUES (e.g. unstable 1 hour, neutral 6 hours,stable 12 hours).TOP OF BOUNDARY LAYER Cory Cripe. Some rights reserved. License: CC BY-NC 3.0.This content is excluded from our Creative Commons license.For more information, see http://ocw.mit.edu/help/faq-fair-use/.3. USE TEMPERATURE SOUNDINGS OR HAZE LAYER HEIGHT TO ESTIMATE Z2

COMPONENTS OF ATMOSPHERIC CHEMISTRY MODELSDYNAMICAL EQUATIONSWinds , Eddy diffusion coefficientsMASS CONTINUITY EQUATIONMOMENTUM EQUATIONSTemperatureTHERMODYNAMIC EQUATIONCHEMICALRatesforHeating Pi - Li -EQUATIONSU.VrFophFluxes.([i]V) ntioiaocissod esot rat{ t RADIATIONForUnpredictedgreen housegases usescenarios orextra polationsFor Source gasesuse predictions,extra polationsor scenarios [i]Concentrations(O3, etc.)Rates for Chemistry{CONTINUITY EQUATIONSTRANSPORT,CHEMISTRY ANDRADIATIONCOMPONENTSIN COMPLEX 3DMODELSInteractions Between Air Pollution and ClimateStratosphereUVO2NO2O3NOO2UVOHHNO3O( 4CO2OHCFCsBCSO2Biosphere & Human ActivityGreenhouse GasesPrimary & Secondary PollutantsAbsorbing Aerosols (BC)Reactive Free Radical/AtomLess Reactive RadicalsReflective AerosolsFigure by MIT OpenCourseWare.3

The spatialgridWe divide the earth’satmosphere into afinite number of boxes(grid cells).Assume that eachvariable has the samevalue throughout thebox.Write a budget for eacheach box, defining thechanges within thebox, and the flowsbetween the boxes.Figure Henderson-Sellers: A ClimateModeling Primer. John Wiley & Sons, Inc. All rights reserved. This content is excluded from our CreativeCommons license. For more information, see http://ocw.mit.edu/help/faq-fair-use/.4

Air Pollution and Human Health(Reference: Adapted from http://www.air-quality.org.uk/18.php)Introduction Pollution-related health problems result from primary pollutants such as sulfurdioxide, nitrogen dioxide, and some particulates, and secondary pollutants like ozone andparticulates produced from primary gas-phase pollutants.Particulates The extent to which particulates are considered harmful depends largely on theircomposition. Sea salt, for example, is believed to have a positive effect on health. Man-madesources of particulates, however, are rarely harmless. In towns and cities, these areextensively from diesel vehicle exhausts. The effects of man-made particulate emissions areconsidered detrimental due to their composition, containing mainly unburned fuel oil andpolycyclic aromatic hydrocarbons (PAHs) that are known to be carcinogenic amonglaboratory animals. Particulates may originate from many other sources including cementmanufacturing processes, incineration and power generation, so localized particulate pollutionis common. The sizes of particles are important when assessing their effects on health. PM2.5and PM10 as well as total suspended particulates are routinely monitored. This is due to thefact that particles of less than 2.5-10 micro-meters (mm) in diameter can penetratedeep into the lung and cause more damage, as opposed to larger particles that may befiltered out through the airways' natural mechanisms.Ozone Ozone is created by the action of sunlight on CO, volatile organic compounds (VOCs)and nitrogen oxides over 1-3 day time periods. This results in ozone being widely dispersedas a pollutant, and can form in greater concentrations in rural areas. As ozone concentrationsare particularly dependant on sunlight, episodes are always likely to develop followingsustained periods of warmth and calm weather. Ozone is a toxic gas that can bringirreversible damage to the respiratory tract and lung tissue if delivered in highquantities. Levels during air pollution episodes range up to 100-250 ppb (0.1-0.25ppm). At these concentrations ozone impairs lung function and causes irritation tothe respiratory tract. Asthmatics are especially affected.5

Oxides of Nitrogen The oxides of most concern are nitric oxide (NO) and nitrogen dioxide(NO2). The latter is more damaging to health, due to the toxic nature of this gas. NOis emitted to the atmosphere as a primary pollutant, from traffic and power stations, and isoxidized to nitrogen dioxide following dispersal. Health effects of exposure to NO2 includeshortness of breath and chest pains. The effects of NO include changes to lung function at highconcentrations.Carbon Monoxide Carbon monoxide combines with hemoglobin, the oxygen carryingcomponent of the blood stream, to form carboxy-hemoglobin (COHb) which can be lifethreatening in high doses. The effects of CO pollution are more damaging to pregnant womenand their fetus. Research into smoking during pregnancy shows that concentrations within theblood stream of unborn infants is as high as 12%, causing retardation of the unborn child'sgrowth and mental development.Lead Lead is still a serious air pollutant especially to those living near to areas of dense trafficin cities where leaded fuel is still used or to coal-fired power plants. Damage to the centralnervous system, kidneys and brain can result when levels in the blood reachconcentrations of 800 mg/liter. Much of the concern regarding pollution from lead centersaround its effects on child health. Children exhibit vulnerability to the toxic effects of lead atmuch lower concentrations than for adults. There is a strong link between high lead exposuresand impaired intelligence.Sulfur dioxide The health effects of sulfur dioxide include heart disease and bronchitis. SO2emissions have been significantly reduced through legislative measures in developed countries.Asthmatics are especially sensitive for whom concentrations above 125 ppb may result in a fallin lung function. Tightness in the chest and coughing may also result at levels approaching 400ppb. At levels above 400 ppb the lung function of asthmatics may be impaired to theextent that medical help is required. Sulfur dioxide pollution is more harmful whenparticulate and other pollution concentrations are also high (the synergistic effect).6

Volatile Organic Compounds (VOCs)Some VOCs are directly harmful, including: Benzene which may increase susceptibility toleukemia, if exposure is maintained over a period of time; Polycyclic Aromatic Hydrocarbons(PAH) some of which can cause cancer (there are several hundred different forms of PAH, andsources can be both natural and man-made); Dioxins, whose sources include manufacturing oforganic compounds as well as the incineration of wastes and various other combustionprocesses involving chlorinated compounds, and which has health effects due to inhalationand ingestion (e.g. dioxins entering the food chain from soils); 1,3 Butadiene, for which there isan apparent correlation between exposure and a higher risk of cancer, and which is producedfrom manufacturing of synthetic rubbers, gasoline-driven vehicles and cigarette smoke.General Air Quality ProblemsAir quality indoors Many different compounds are contained in tobacco smoke, including carbonmonoxide, ammonia, dioxins and PAH; the latter two are thought to be carcinogenic. Othersources of indoor pollution include particulates from mineral fibers as well as household dust.Dust in buildings is known to cause problems including fatigue and nausea. One of the mostpressing concerns with indoor air pollution is with carbon monoxide built up from gas, oil orwood fired appliances. Open gas flames and fire places also produce BC.Asthma and air pollution There has been a steady rise in the number of reported asthma casessince the 1970s, and air pollution problems are believed to be a significant (but not sole)contributor to the rise. High concentrations of nitrogen dioxide, sulfur dioxide, ozone andparticulates (especially PM10) can all trigger breathing difficulties in asthmatics.7

NATIONALAMBIENTAIR QUALITYSTANDARDS(NAAQS)8

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OZONE MONITORINGNETWORKIN NEW ENGLANDHigh concentrations of ozone near groundlevel can be harmful to people, animals,crops, and other materials. Ozone canirritate your respiratory system, causingyou to start coughing, feel an irritation inyour throat and/or experience anuncomfortable sensation in your chest.Ozone can aggravate asthma, and caninflame and damage cells that line yourlungs. Ozone may also aggravate chroniclung diseases such as emphysema andbronchitis and reduce the immunesystem's ability to fight off bacterialinfections in the respiratory system. Lastly,ozone may cause permanent lungdamage. These effects can be worse inchildren and exercising adultsImage courtesy of EPA.10

O3 at BOSTON - LONG ISLAND STATION (Operating 1999 to Present)YearTotalDays 76Sept260.073Aug 3200600.083June220.083July 20.083July180.079July 00410.094June 0.083June250.078June260.078July 42002100.126Aug130.117Aug140.1020.102Sept 9200190.111June200.107June190.100Aug 20.094July24200000.084June100.073June 10.072Aug 90.070June 2199940.102July160.100June240.089June 10.087May31July 3MAP**11

REGIONAL OZONE HEALTH ALERTS IN NEW ENGLANDBASED ON THE MONITORING NETWORK. Human health isaffected by exposure to ozone expressed as a function of theAOT40 Index (AOT40 hourly ozone exposure above 40 ppb inunits of ppb.hr/mo; see earlier lecture for USA AOT40 map)Image courtesy of EPA.12

Air Pollution Economic Effects(Yang et al, Report 113, MIT Joint Program on the Science & Policy of Global Change:http://globalchange.mit.edu) Approach Extensive data set on epidemiological effects of airpollution exposure Resultant illness, death, demand for medical services Lost labor, leisure, diversion of resources to medical andhealth services introduced into MIT economic model Results based on historical pollution levels evaluated US benefit of air pollution regulation, andremaining burden of air pollution (1975-2000)13

Change in Welfare450Benefit of Policy is avoidedhealth costs due to thepolicy.Remaining Cost of Pollutiondecreases due to lowerpollution levels, but is offsetby increases due to risingincome and population.Welfare is a measure of totalconsumption of goods andservices. billions 1997 USD400350300250200150Benefit of Policy100Cost of ts of air pollution regulation and costs of remaining pollution.Figure by MIT OpenCourseWare.Welfare350200250 billions USD billions USD300200150100500197519801985 1990Year(a) Benefits199515010050019752000PMO319801985 1990Year19952000(b) Costs by PollutantFigure by MIT OpenCourseWare.14

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Remaining Cost of Pollution decreases due to lower pollution levels, but is offset by increases due to rising income and population. Welfare is a measure of total consumption of goods and services. Change in Welfare Benefits of air pollution regulation and costs of remaining pollution. billions 1997 USD Year 1975 0 50 100 150 250 350 450