This paper describes a mobile differential absorption LIDAR system, which operates in the UV, visible, and IR spectral regions. This system can measure a range of important air pollutants emitted by industry, including SO2, NO2, NO, HCl, benzene, toluene, and a large range of other VOC's. These species can be monitored at fugitive and flammable levels at ranges of up to 1 km (for IR measurements) and 3 km (for UV measurements). Examples of measurements of fluxes emitted from large scale industrial sties are presented and discussed. Comparisons are given between measured fluxes and those calculated using the US Environmental Protection Agency's and American Petroleum Institute's standard procedures for estimating industrial emissions. The fluxes measured by DIAL are higher than the values derived from the API procedures. Possible reasons for discrepancies between the measured results and the EPA/API estimation procedures will be discussed.