California Air Resources Board

When the representative meteorological data necessary for your AERMOD run is not available, you may want to create the screening meteorological data to perform a screening analysis using US EPA’s AERSCREEN model.

AERSCREEN is a screening-level air quality model based on AERMOD. The AERSCREEN model consists of two main components - the MAKEMET program; and the AERSCREEN command-prompt interface program. AERSCREEN interfaces with MAKEMET for generating the application specific worst-case meteorological matrix using representative ambient air temperatures, minimum wind speed, and site specific surface characteristics such as albedo, Bowen ratio, and surface roughness. The AERSCREEN model interfaces with AERMAP (terrain processor in AERMOD) and BPIPPRM (building downwash tool in AERMOD) to process terrain and building information respectively, and interfaces with the AERMOD model utilizing the SCREEN option to perform the modeling runs. The AERSCREEN program generates estimates of worst-case 1-hour concentrations for a single source, and also automatically provides impacts for other averaging period such as 3-hr, 8-hr, 24-hr and annual ratios currently implemented in AERSCREEN. The screening analysis with AERSCREEN should be consistent with the guidance contained in EPA’s Guideline on Air Quality Models and appropriate screening modeling documents such as the Screening Procedures for Estimating the Air Quality Impact of Stationary Sources (EPA, 1992a).

The data for AERSCREEN are made available for your convenience. These data are provided by Air Quality Planning and Science Division of CARB. The data include a note for users, all air-basin wide temperature tables, and a surface characteristics file. The air-basin wide temperature tables include maximum and minimum temperatures by seasons - winter, spring, summer and fall for each meteorological monitoring site within an air-basin. The temperature datasets were prepared from CARB’s meteorological data warehouse for the years 2004-2013. It included all valid sites, except CIMIS operated monitoring stations that report measurements taken at 2-meter height whereas other stations report measurements typically at 10-meter height level. In general, the temperature data were grouped by season in order to be consistent with seasonally varying surface characteristics such as albedo, Bowen ratio and surface roughness for each land cover type. It was found that 10-year dataset was long enough to capture ENSO (El Nino Southern Oscillation) effects on temperature, and generally be able to represent areas surrounding a specific meteorological monitoring station.

You may go to the map page of the ARB designated air basins to find out which air basin your project is located in and what files need to be downloaded.  A list of air basins and corresponding counties is also available on the map page.  You can also download the air basin KMZ file, then open it in Google Earth or other geographic browsers to see the locations of air airbasins and to determine what files to download for your project.

CARB Disclaimer

The fact that CARB has supplied you with these data does not mean that the CARB will place its approval on subsequent applications. We must emphasize that the models must be applied properly with appropriate input data which is consistent with their formulation, testing, and assumptions.

Download All Files (contains a note for users, all air-basin wide temperature tables, and a surface characteristics file for AERSCREEN.

Download Individual AERSCREEN Files

1. User Instructions
2. Surface characteristics input data
3. Great Basin Valleys air basin temperature input data
4. Lake County air basin temperature input data
5. Lake Tahoe air basin temperature input data
6. Mojave Desert air basin temperature input data
7. Mountain Counties air basin temperature input data
8. North Central Coast air basin temperature input data
9. North Coast air basin temperature input data
10. Northeast Plateau air basin temperature input data
11. Sacramento Valley air basin temperature input data
12. Salton Sea air basin temperature input data
13. San Diego air basin temperature input data
14. San Francisco Bay Area air basin temperature input data
15. San Joaquin Valley air basin temperature input data
16. South Central Coast air basin temperature input data
17. South Coast air basin temperature input data