DNR has made new meteorological data available for use in the AERMOD dispersion model. The data consist of 19 five-year sets for the period of 2005-2009. Nine new sites have been added that were not included in the 2000-2004 datasets. Changes to the locations represented by several meteorological stations, as well as recent upgrades to EPA's meteorological data preprocessor (AERMET) and the inclusion of one minute wind data using EPA's new AERMINUTE preprocessor have results for the 2005-2009 data being substantially different from the 2000-2004 data.

DNR tested the sensitivity of AERMOD to the changes introduced in the new datasets and found that concentrations increase tend to increase for the shortest averaging periods (1-hour and 3-hour) and decrease for longer averaging periods (8-hour, 24-hour, and annual).

Facilities submitting modeling as part of an application should begin using the new dataset immediately. The 2000-2004 dataset will remain available until June 30, 2012 and will only be accepted if it has already been approved in a dispersion modeling protocol.

To download the new data or for more information, please visit the Air Quality Bureau Pre-processed Meterological Data for AERMOD webpage.