CONCEPTUAL MODELING PROTOCOL FOR THE NEIGHBORHOOD ASSESSMENT PROGRAM

Objectives of Modeling Protocol ldevelop and evaluate methodologies to estimate annual average concentrations of various pollutants released from multiple sources at the neighborhood scale (Barrio Logan) lrecommend a method to perform neighborhood assessments

Size of Modeling Domain lMicro-scale (Neighborhood scale) modeling - receptors located near emission sources, i.e., meters to few kilometers from the sources lRegional scale modeling - source and receptor distances of several kilometers, to hundreds of kilometers, to the size of air basins

Air Toxic Pollutants To Be Modeled lMicro-scale modeling - more than 100 pollutants, including: Acetaldehyde, Acrolein, Acrylonitrile, Arsenic, Benzene, Beryllium, 1,3- Butadiene, Cadmium, Chloroform, Hexavalent Chromium, Ethylene Dibromide, Dioxin, Diesel PM, Formaldehyde, Hydrazine, Lead, Manganese, Methylene Chloride, Mercury, Nickel, (PCBs), Perchloroethylene, Trichloroethylene, Vinyl Chloride lRegional modeling - 30 pollutants: Acetaldehyde, Acrolein, Arsenic, Benzene, Beryllium, 1,3-Butadiene, Cadmium, Carbon Tetrachloride, Chloroform, Diesel PM, Ethylene Dichloride, Ethylene Oxide, Formaldehyde, Hexavalent Chromium, Iron, Lead, Manganese, Mercury, Methylene Chloride, MTBE, Nickel, o-Dichlorobenzene, p-Dichlorobenzene, Perchloroethylene, Styrene, Toluene, Trichloroethylene, Vinyl Chloride, Xylenes, Zinc

Micro-scale Models to Estimate Annual Concentrations lTraditional Models l ISCST3 - U.S. EPA regulatory model l CALINE - U.S. EPA approved model for line sources lAdvanced Models l AERMOD - recommended as replacement for ISCST3 l CALPUFF- recommended model for complex terrain and for long-range transport lNew and Emerging Models l Lagrangian particle dispersion model - state-of-the- science short-range model that estimates concentrations at scales of meters to tens of meters from a source

Input Data For Micro-scale Modeling  meteorology (hourly surface observations from local airports and on-site measurements)  point source emissions (including some traditional “area wide” sources, e.g. dry cleaners)  mobile source emissions (hourly traffic volumes and emission factors)  source configurations (e.g., stack heights)  receptor locations

Micro-scale Modeling Domain - Mobile Sources

Micro-scale Modeling Domain - Point Sources

Regional Models To Estimate Annual Concentrations lTraditional Models UAM (Urban Airshed Model) - used for air quality planning lAdvanced Models Models-3 - state-of-science model developed by U.S. EPA

Regional Scale Modeling Objective: Estimate annual concentrations due to transport of pollutants from distant sources or air basin(s) that contribute to neighborhood areas (background concentrations) Improvements to Regional Scale Modeling: l Incorporate SAPRC 99 and air toxic chemistry l Apply over air basin(s) using an entire year of data for meteorology and emissions

Inputs For Regional Scale Modeling lDevelopment of Regional Emissions Inventory l Update the 1998 database to reflect seasonal variations in emissions and update toxic emissions as well l Utilize latest version of EMFAC2000 to estimate motor vehicle emissions lDevelopment of Meteorological Inputs for Regional Air Quality Models l CALMET - a diagnostic model that requires observational data for winds and temperature l MM5 - an advanced state-of-science prognostic meteorological model to simulate winds and temperatures

Location of the coarse and fine grids used in MM5 model

CALMET - Wind Fields (Morning)

CALMET - Wind Fields (Afternoon)

MM5 - Wind Fields (Afternoon)

Regional scale air quality modeling domain

Model Performance Evaluation lA scientific process to ensure models are working properly and are estimating reliable concentrations lCompare model estimates of concentrations with observational data and conduct operational and diagnostic evaluation lFollow the procedures identified in ARB's Technical Guidance Document on modeling. lStandard statistical techniques such as bias and gross error will be calculated for annual model estimates of concentrations as well as for monthly and seasonal averaging times

Databases For Evaluating Model Performance Micro-scale models: lConduct a field monitoring study to collect a database for short-range dispersion in urban neighborhood areas lField study includes release of a tracer gas, bag sampling and continuous monitoring of the tracer gas, and meteorological measurements which include six sonic anemometers and a mini-sodar lSampling will be conducted over a one week period for four seasons of year at several sites lFunding available for total of 20 weeks of sampling

Databases For Evaluating Model Performance Regional Models: lUse routine meteorological and air quality (criteria and toxic) data collected by air districts and ARB lUtilize data collected from recent studies (SCOS97 and CRPAQS/CCOS) and other data gathered from special monitoring studies

Recommendations From Study lIdentify which micro-scale and regional models are best suited for assessing neighborhood impacts lDevelop recommendations for guidelines to determine the cumulative impacts posed by air pollutants at the neighborhood-scale lShare modeling results and recommendations with U.S. EPA and other interested groups