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VOC’s/CFC’s and Ozone Dan Gloudemans
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Presentation Overview VOC’s Ozone Formation, natural/other VOC’s Destruction, natural/other CFC’s Measurement / EPA AQI Ozone hole/ Home Ozone exposure What is being done about Ozone? Clean Air Act OTC CARB/OTC Ozone in the Midwest?
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Brief VOC overview Organic Compound – contains carbon and hydrogen Ie: octane, butane…, sugar VOC = Volatile Organic Compound, organics that evaporate easily VOC’s are compounds that lead to the formation of ground level Ozone – “smog” VOC’s can be found in anything from paints to deodorant
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Good/Bad Ozone – “Good up high, bad nearby” Ozone is beneficial in Stratosphere blocks many ultra violet rays (λ < 320 nm) But is very harmful in Troposphere it is a highly reactive gas that can affect the normal functioning of the lungs
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Formation of Ozone (O3) “natural” Ozone first formed - ~500 million years ago, after release of Oxygen Ozone formation – atomic Oxygen Most natural ozone formation occurs in the Tropics “Chapman reactions” So called after S. Chapman who is famous for his paper 'A theory of upper-atmosphere ozone, Mem. Roy. Meteorol. Soc.' in 1930 which set out the first theoretical explanation of the ozone layer in the stratosphere.
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… Other formation of Ozone - Groundlevel Photochemical reaction of NOx (collectively NO and NO2) with VOC’s in the presence of sunlight
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Destruction of Ozone - “natural” Ozone destruction by UV radiation – very similar fashion Ozone concentration highest in the poles!
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…Other Destruction of Ozone CFC’s among others Organic molecules – H’s replaced with Halogens Cl and F
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Measurement of Ozone Reported in Dobson Units (DU) Imagine all ozone on the surface of the earth evenly (vs. reality of the strato/troposhpere) 1 DU = 0.01 mm of Ozone 300 DU a typical value Thus, 300 DU = 3 mm O3 spread evenly across earth
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AQI – Air Quality Index Measures presence of 5 pollutants ground-level ozone particle pollution carbon monoxide sulfur dioxide nitrogen dioxide 0-500 Scale 100 is National Air quality standard ~200 – unhealthy to very unhealty – whole population could be affected >300 - Hazardous
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The “Ozone Hole” Over Antarctica First noticed in 1970’s British Antarctic Survey (BAS) First discovered/measured in 1985 TOMS (Total Ozone Mapping Spectrometer). Findings thought faulty Eventually confirmed Graph shows measurements above the Halley Bay research station
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Home Exposure to VOC’s EPA's Total Exposure Assessment Methodology (TEAM) Found that VOC level are often 2 to 5 times higher indoors The relative danger varies greatly Length and level of exposure nose and throat discomfort, headache, allergic skin reaction, nausea, fatigue, dizziness.
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What is being done about Ozone? US adopted Montreal Protocol in 1987 – limit CFC’s States most dangerous phased out by 2000 Clean Air Act All class I substances outlawed by Jan 1 2000 chlorofluorocarbon-11 (CFC–11) chlorofluorocarbon- 12 (CFC–12) + others All class II substances outlawed by Jan 1 2030 hydrochlorofluorocarbon-21 + various other Ozone “Action Days” Days > 90F, little or no wind Encourage to reduce emmisions, and protect
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OTC – Regional effort OTC = Ozone Transport Commission Several northeastern states (13 total) Created under Clean Air Act (CAA) amendments in 1990 Focus on Ground Level Ozone - specifically NOx emissions - during May – Sept “Ozone Season” NOx Budget Program – sell or store unused allowances Regional emissions trading program
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OTC - Progress
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OTC – but room for More progress
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CARB/OTC California Air Resource Board In addition to NOx, these two regulate VOC emmisions Consumer Products
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Wisconsin Ozone? Yes! Southeastern Wisconsin During Action Days Combining errands Fueling car gas tanks at night Mowing lawns after 6:00 p.m Properly inflating vehicle tires Carpooling, biking, walking or riding the bus to work
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Midwestern Ozone problem areas US EPA, Region 5 What about Minnesota?
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Questions?
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References EPA – “air Now” How VOCs Contribute To Formation Of Ground-Level Ozone. Chemical & Engineering News, 1/24/2005, Vol. 83 Issue 4, p26, 1/3p; (AN 16120478) How VOCs Contribute To Formation Of Ground-Level Ozone. Chemical & Engineering News; 1/24/2005, Vol. 83 Issue 4, p25, 3p, 1c “SMOG, POLICY AND CHEMISTRY.” Chemical & Engineering News http://www.dnr.state.wi.us/org/aw/air/ozone/OzActionNotice.htm
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