An emission inventory for an industrial or commercial enterprise is a compilation of information from which one can calculate or estimate the rates (quantity per unit time) at which pollutants are released to the environment. For purposes of this chapter, only the emissions that contaminate workroom or community air are considered; emissions to surface or ground water, to soil, or to other environmental receptors are treated only as they may, in turn, result directly in emissions to workplace or community air.
An emission inventory may be simple or complex. A rudimentary inventory may consist of source location, date, identification of process, a qualitative listing of materials used, and an index of size (e.g. annual production rate) for the subject enterprise. Such an inventory, along with emission factors generated by studies of similar processes, will permit the making of an estimate of annual emissions. A comprehensive emission inventory, on the other hand, may contain sufficient detail to permit quantification of emissions, including temporal variations, for a number of specific materials from each point of release in a complex industrial process.
An inventory of emissions, along with various other kinds of companion information, discussed in this chapter, permits the making of estimates of the nature, and sometimes the intensity, of exposures to airborne agents in workplaces or in the community. The level of detail needed and achievable for the inventory depends both on the purposes for which it is to be used and the data sources, or data generating efforts, which can be utilized.