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Microscale Air Dispersion Modeling Status Community Health Neighborhood Assessment Program. Working Draft March 28, 2001. Three Types of Inventory . Area-Wide Sources (e.g. consumer products) Motor Vehicle (e.g. freeway) Point Source Traditional Points (e.g. NASCO)
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Microscale Air Dispersion Modeling StatusCommunity HealthNeighborhood Assessment Program Working Draft March 28, 2001
Three Types of Inventory • Area-Wide Sources (e.g. consumer products) • Motor Vehicle (e.g. freeway) • Point Source • Traditional Points (e.g. NASCO) • Includes Some “Area-Wide” Sources (e.g. auto repair)
Models for Microscale • ISCST3 • Traditional workhorse model • AERMOD • Latest USEPA model for microscale • Calpuff • 3 dimensional wind field • CALINE • EPA line source model • Lagrangian Particle Dispersion Model • New emerging model
Some Facts • 600+ Individual Point Sources • 64 Individual Pollutants • Diurnal Variation of Emissions • Meteorological Data from Memorial Jr High • November 1999 thru October 2000 • Coarse Grid Receptor Field (500 m grid spacing) • Fine Grid Receptor Field (50m-100m grid spacing)
ISCST3 Results • Preliminary • Formaldehyde • Cr(VI) • Point Sources Only
AERMOD Results • Preliminary • Formaldehyde • Cr(VI) • Point Sources Only
CAL3QHC Results • Preliminary • Benzene • Diesel Exhaust PM • Motor Vehicle Only
CALPUFF Modeling System • CALMET • Multiple sources of meteorological data • 3-dimensional wind field • CALPUFF • non-steady state modeling (i,e., puff model)
CALMETLand type used to calculate heat flux and turbulence parameters
CALPUFF Non-steady State Puffs(An Example - Next Two Slides) • November 11, 1999 • Mn emissions terminate after the 4pm hour • For the 5pm hour • AERMOD and ISC • show zero concentration • CALPUFF • shows non-zero concentration • emission puff still in domain
CALPUFF(Preliminary) Mn Annual avg. conc., point source emissions
Microscale Follow Up Work • Sensitivity studies (e.g., receptor field, source configuration) • Overlay concentration fields from line sources and point sources • Update inventory based on modeling results (iterative procedure) • Continue with CALPUFF analysis • Evaluate Model Performance