Question: I am trying to model several facilities in a county that has UTM zone 16/17 run right through the county.  I have sources on both sides of the line. Is there any way in BEEST to enter the UTM zone the facility is in so that I don't have to set up two models?

Answer: BEEST supports only one UTM zone per model because the AERMOD, ISCST3, and ISC-PRIME models do not support multiple UTM zones. The zone is set in the "AERMAP Options" tab seen when you click the "Run AERMAP" button. After you set this value, there is not a way to enter UTM zones for individual sources. A solution is to set the model zone so that the majority of sources are in this zone and then convert the coordinates for the rest of the sources to have the same zone value.