How Are Fugitive Dust Sources Modeled?
Fugitive dust (particulate matter) from sources such as coal piles and haul trucks is difficult to model for a number of reasons. First of all, it is difficult to establish an emission rate because of the uncertainty of the emission factors. Also, the conditions at each location can vary so widely that it is impossible to categorize sources. Due to the nature of fugitive dust sources, the WDNR does not usually model these sources. The impact of fugitive dust sources can be determined upon request. As improvements are made to the science necessary for understanding fugitive sources, this stance will change. There are fugitive emissions that should be modeled, however. These include emissions that are created within a facility building that are not vented directly to a stack and small emission units that are written together in the permit. Examples include natural gas heaters with roof vents, foundry furnaces, and dip tanks vented to general building ventilation.
