AERSCREEN:Status and UpdateJames Thurman9thModeling ConferenceU.S. EPA/OAQPS/AQAD/AQMGthurman.james@epa.gov**Overview • AERSCREEN workgroup** **• Description and Features • Initial test results** **• MAKEMET • AERSCREEN stages** **• Questions AERSCREEN Finalization Workgroup** • Jim Haywood, Chair, Michigan DEQ• Karen Wesson, EPA• Roger Brode, EPA (formerly with MACTEC)• James Thurman, EPA• Bob Paine, ENSR• Lloyd Schulman, TRC• Acknowledge Herman Wong, EPA Region10AERSCREEN: Description**• AERSCREEN is a DOS tool that runs AERMOD in a “screening” mode for a single source** **– calls MAKEMET, BPIPPRM and AERMAP to generate necessary AERMOD inputs** **• Spring 2008, incorporates output from AERSURFACE b ut** **does not currently call AERSURFACE – SCREEN option added to AERMOD in 1995 forces** **model to calculate centerline concentration for eac h** **source/receptor/meteorology combination • Output limited to to 1-hour averages and NOCHKD sel** **ected option to eliminate date sequence checking** **AERSCREEN Features • Program developed by Jim Haywood, MI DEQ** **– Data entered via prompts or by input file – Source types: point, volume, rectangular area, ci** **rcular area, and flare** **– Flat or complex terrain • AERSCREEN calls AERMAP for complex terrain process** **ing • Terrain not used for rectangular area sources** **– PRIME building downwash • Specify stack location and direction relative to b** **uilding center • Specify building dimensions (height, horizontal di** **mensions) • Direction of long building dimension from north** **• Not used for area or volume sources • AERSCREEN calls BPIPPRM** **– No deposition – MAKEMET meteorology** **• Specify min and max temperatures, minimum wind spe ed,** **anemometer height and surface characteristics • Internal matrices of other meteorological paramete** **rs AERSCREEN Features** **• User can specify – Probe distance for terrain processing** **• Default of 5 km for flat terrain (with or without building** **downwash) or rectangular area sources – Flagpole receptors** **– Elevation of source location for PROFBASE (even fo r** **flat terrain) • Elevation above sea level for potential temperatur** **e profile – Rural or urban (if urban, urban population)** **– Ambient air distance (fence line distance) – Source location in geographic or UTM coordinates** **• Search routine to find worst case impact – RANKFILE output in AERMOD** **– Concentration, date, direction, distance, and meteorology** **AERSCREEN Features • Routine to find maximum concentration for** **automatic receptor distances • Re-Use of Previous AERSCREEN Run Files** **• Performs errors checks on AERMOD and AERMAP output and writes log file of** **AERSCREEN run • Includes factors for 3-hour, 8-hour, 24-hour and** **annual averages – based on upper bound of SCREEN3 factors** **– 3-hour: 1.0 (0.90**±**0.10) – 8-hour: 0.9 (0.70** ±**0.20) – 24-hour: 0.6 (0.40** ±**0.20) – Annual: 0.1 (0.08** ±**0.02)**Figure 1: AERSCREEN Averaging Period Ratios vs. Plume Height(line shows 95th-percentile and error bars show 90thand 98thpercentiles)**0.0 0.1** **0.2 0.3** **0.4 0.5** **0.6 0.7** **0.8 0.9** **1.0 0 50 100 150 200** **3-hr 8-hr** **24-hr Annual** **SCREEN 3-hr SCREEN 8-hr** **SCREEN 24-hr SCREEN Ann** **Plume height (m) AERSCREEN Tests** **• Significant testing to date shows good results across wide range of applications** **• “Good” defined as reasonable conservatism compared to AERMOD** **refined estimates 1.05** **0.98 2.98** **168 Flat Terrain** **Non-downwash Rural & Urban** **Roger Brode 2.23** **1.08 7.46** **28 Complex Terrain** **Bob Paine 1.18** **0.96 4.56** **168 Complex Terrain** **Varying Source/ Terrain Distance** **Roger Brode 1.49** **0.97 2.18** **26 Stack non-downwash** **Karen Wesson 1.17** **0.96 2.54** **32 Stack downwash** **Karen Wesson 2.35** **1.09 5.20** **7 Miscellaneous** **Jim Haywood Median** **Ratio Min.** **Ratio Max.** **Ratio No. of** **sources Type** **Database MAKEMET** **• MAKEMET loops through several meteorological parameters:** **– Wind speed (stable and convective) – Cloud cover (stable and convective)** **– Max/min ambient temp (stable and convective) – Solar elevation angle (stable and convective)** **– Convective velocity scale (w*) (convective only)****– Mechanical mixing heights (stable only)****• Uses AERMET subroutines to calculate u* and L, and****also calculates convective mixing heights • For AERSCREEN, uses wind direction of 270** **• Generates surface and profile files for running AE RMOD** **Surface Characteristics and MAKEMET • Three methods of surface characteristics into** **AERSCREEN 1. User defined: annual, non-sector based** **2. Seasonal tables from AERMET User’s Guide (Tables 4-1, 4-2, 4-3)** **• User specifies dominant land use type and moisture conditions** **– Water, deciduous forest, coniferous forest, swamp, cultivated land,** **grassland, urban, desert shrubland – Moisture for Bowen ratio: average, dry, or wet** **• Non-sector based 3. AERSURFACE output** **• User enters AERSURFACE output filename or AERMET s tage 3 input** **filename • Annual, seasonal, or monthly** **• 1 to 12 surface roughness sectors sectors • AERSURFACE is run for the source location** **• MAKEMET is run for each temporal, sector combinati on** **and met files generated for each combination**Input and validate dataGenerate meteorological files and run BPIPPRM and AERMAP for source ifnecessaryIs there a source-receptordirectiondependency?flat terrain and no downwash andnot a rectangular area source,execute PROBEterrain and/or downwash orrectangular area source, executeFLOWSECTORREFINEOutputUser actionsProgram actions**No Yes** **AERSCREEN Stages & Steps**Example input fileValidationpage**Summary of stages • PROBE** **– 5 km default probe distance (25 m spacing) in one direction** **– AERMOD executed for each temporal/spatial sector o f SC** **• FLOWSECTOR – Rectangular area sources** **• 5 km probe distance (25 m spacing) for 5 degree di agonals** **• AERMOD run for each SC temporal/spatial sector for each diagonal** **– Other sources • Receptors every 10 degrees out to probe distance** **• Direction specific terrain and projected building dimensions used** **• AERMOD run for each SC temporal sector – Upwind spatial sector of direction being processed** **• REFINE – Find overall maximum concentration from PROBE or F** **LOWSECTOR – Use meteorology and SC associated with maximum con** **centration – If terrain and/or downwash, use terrain heights an** **d projected building dimensions of direction of maximum concentration** **– Refine receptor spacing to 1, 2, or 5 m increments 5 km** PROBE051015202530FLOWSECTOR: rectangular areaFLOWSECTOR: other sourcesxyxyxy-----------------------------------------------------------------------------********************** AERSCREEN MAXIMUM IMPACT SUMMARY *********************-----------------------------------------------------------------------------MAXIMUM SCALED SCALED SCALED SCALED1-HOUR 3-HOUR 8-HOUR 24-HOUR ANNUALCALCULATION CONC CONC CONC CONC CONCPROCEDURE (ug/m3) (ug/m3) (ug/m3)(ug/m3) (ug/m3)--------------- ---------- ---------- ---------- ---------- ----------ELEVATED TERRAIN 0.3652E+05 0.3652E+05 0.3287E+050.2191E+05 3652.DISTANCE FROM SOURCE 139.0 meters directed toward 180 degreesRECEPTOR HEIGHT -5.02 metersIMPACT AT THEAMBIENT BOUNDARY 0.1552E+05 0.1552E+05 0.1397E+059310. 1552.DISTANCE FROM SOURCE 30.0 meters directed toward 110 degreesRECEPTOR HEIGHT -5.88 meters**Future • Draft release package:** **– AERSCREEN and MAKEMET executables – User can download BPIPPRM, AERMOD,** **AERMAP and AERSURFACE from SCRAM website** **http://www.epa.gov/scram001 – User documentation and example case**