Performing an air dispersion modeling analysis often results in the creation of many files on your computer. Besides input and output files, projects can contain numerous meteorological data, terrain data, digital basemaps, and external data files. Whether you are modeling a simple scenario with AERMOD or a complex regional study with CALPUFF, there will be many different file types to account for and manage.
One of the model updates made by the U.S. EPA earlier this year was the release of the new AERMINUTE executable. AERMINUTE processes 1-minute ASOS wind data to generate hourly wind speed and wind direction averages to supplement data within standard hourly surface data files. Meteorological stations throughout the United States have gradually replaced manned observations with Automated Surface Observing Stations (ASOS). This led to a marked increase in missing or calm hours in the hourly observations which degrades the quality of air dispersion modeling analyses. AERMINUTE provides much higher wind data quality by processing the raw 1-minute data logged by the automated station.
When using the US EPA AERMOD model, it is often necessary to give the same properties to several sources. For example, for a facility that has seasonal operations, the same variable emission rate may apply to many sources. Rather than entering the same information repeatedly, it is possible to use source ranges to specify a series of sources to which the same information will be applied.