The 1996 National Toxics Inventory and its Role in the Government Performance and Results Act

摘要

The Environmental Protection Agency has routinely collected emissions inventory data for criteria pollutants for about 20 years. The 1990 amendments to the Clean Air Act (CAA) provided a new focus on hazardous air pollutants (HAPs) that resulted in a similar need for HAP emissions inventories. As a result the EPA's Office of Air Quality Planning and Standards (OAQPS) has produced several inventory products that provide data for specific CAA needs. Examples are the seven pollutant (112(c)(6)) and urban program (112(k)) inventories, and the 1993 National Toxics Inventory (NTI). More recently, the Government Performance and Results Act (GPRA) has established the need for a more comprehensive HAP emissions inventory effort that can be used to track EPA's progress over time in reducing HAPs in ambient air. In response to GPRA, EPA has established goals for the Air Toxics Program that require first, a demonstration of HAP emissions reductions, and in later years, a demonstration of reduced risk to the public from HAP emissions. To meet the objective of estimating risk, EPA will need a model-ready emissions inventory in order to perform dispersion and exposure modeling. The OAQPS 1996 NTI will be the first effort to estimate not only HAP emissions on a national scale, but also source-specific parameters necessary for modeling such as location and facility characteristics (stack height, exit velocity, temperature, etc.). The compilation of this huge amount of data presents a significant challenge to OAQPS. Since HAPs estimates have not previously been required, current data is limited and new methodologies for estimating emissions are necessary. In order to begin compiling the necessary data, OAQPS has solicited HAP emissions data from the states. Approximately thirty states have delivered HAP emissions inventories they have voluntarily compiled. This state data varies in completeness, format, and quality. OAQPS will evaluate and supplement the state data and estimate emissions from missing states and from sources not included in state data in order to produce a complete model-ready national 1996 inventory. This paper will discuss OAQPS' plans for establishing the 1996 NTI including methodologies, schedule, format, and review.