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AoH Conference Call October 8, 2004. Air Resource Specialists, Inc. Review of IMPROVE Aerosol Data. Visibility parameters and equations IMPROVE monitoring Regional Haze Rule data guidelines Review of 2002 IMPROVE data (selected sites) Next steps. Definitions of Visibility.
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AoH Conference CallOctober 8, 2004 Air Resource Specialists, Inc.
Review of IMPROVE Aerosol Data • Visibility parameters and equations • IMPROVE monitoring • Regional Haze Rule data guidelines • Review of 2002 IMPROVE data (selected sites) • Next steps
Definitions of Visibility • Visual Qualities - The color, texture, and clarity of a scene • Visual Range (km) - The greatest distance at which a large black object on the horizon can be seen • Extinction/Scattering/Absorption (Mm-1) - The fraction of light lost per unit length along a sight path • Deciview (dv) - An index which is linear with human perception of visibility
Visibility Equations • Extinction is the sum of particle scattering, natural atmospheric scattering, and absorption: bext = bsp + bRayleigh + babs • Extinction can be converted into Visual Range or Deciview: Visual Range (km) = 3912 / bext Deciview (dv) = 10 x ln (bext / 10)
IMPROVE Extinction Equation • bext (Mm-1) = 3 * f(RH) * [Ammonium SULFATE] • + 3 * f(RH) * [Ammonium NITRATE] • + 4 * (1.4) * [ORGANIC CARBON] • + 10 * [ELEMENTAL CARBON] • + 1 * [SOIL] • + 0.6 * [COARSE MASS] • + Rayleigh scattering (typically use 10 Mm-1) • Where: • f(RH) is the relative humidity enhancement factor • Elemental carbon is the only species which absorbs light
IMPROVE Aerosol Sampler Systems • Sulfur>>Sulfate • Soil • PM2.5>> • Coarse Mass • Nitrate • Sulfate • (backup) • Organic Carbon • Elem. Carbon • PM10>> • Coarse Mass
Regional Haze Rule Data Guidelines • Calculate extinction based on IMPROVE equation, using 6 species and monthly f(RH) • Allowed to fill in missing species data with quarterly median values if strict conditions are met • Data completeness: • 50% for all quarters • 75% for the year • No more than 10 consecutive samples missing in a year • Minumum of 3 complete years needed to represent 5 year average • Convert extinction to deciview • Calculate annual 20% best and worst deciview averages
IMPROVE Total Aerosol ExtinctionWorst 20% for 2002 VIEWS web site: http://vista.cira.colostate.edu/views/Web/AnnualSummary/ContourMaps.aspx
IMPROVE Ammonium Sulfate ExtinctionWorst 20% for 2002 VIEWS web site: http://vista.cira.colostate.edu/views/Web/AnnualSummary/ContourMaps.aspx
IMPROVE Ammonium Nitrate ExtinctionWorst 20% for 2002 VIEWS web site: http://vista.cira.colostate.edu/views/Web/AnnualSummary/ContourMaps.aspx
IMPROVE Organic Mass ExtinctionWorst 20% for 2002 VIEWS web site: http://vista.cira.colostate.edu/views/Web/AnnualSummary/ContourMaps.aspx
2002 Data from Selected Sites • Timeline species extinction plots for 6 sites across WRAP: • Spokane Indian Reservation, WA • Medicine Lake, MT (adjacent to Fort Peck) • Rocky Mountain NP, CO • Grand Canyon NP, AZ • Yosemite NP, CA • Crater Lake, OR
Crater LakeRecon. Aerosol Extinction Comparison Avg. extinction: 48.9 Mm-1 Avg. extinction: 24.8 Mm-1
Crater LakeRecon. Aerosol Extinction Comparison Avg. extinction: 24.8 Mm-1 Avg. extinction: 23.9 Mm-1
Grand CanyonRecon. Aerosol Extinction Comparison Avg. extinction: 23.4 Mm-1 Avg. extinction: 21.8 Mm-1
Next Steps • Conference call week of October 18 • Working with RMC to transfer emission and TSSA data files to ARS • Begin adding draft documents to the AoH web site (introductory materials first) • Prepare samples of CIA reports on AoH web site (currently based on available data) • Review agenda for November meeting