A Review of Mobile Source Emissions Inventories in the Mid-Atlantic Region, March 2000, E.H. Pechan & Associates, Inc.

This report analyzes mobile source emissions data for eight major metropolitan areas in the mid-Atlantic Region for 1990 or 1996. It explores the similarities and differences among inventories for metropolitan areas, and it describes differences among various State and national emission inventory estimates. This report identifies important assumptions underlying the calculation of mobile source emissions.

This review showed that differences in methods of calculating emissions for the areas had a significant influence on highway vehicle emission levels. Estimating vehicle speeds by roadway type was the most important analytical difference in emission rates by area.

Methodological differences have evolved for both technical and organizational reasons specific to each State. A common understanding of current methods and an ongoing discussion of future plans would facilitate the use of improved methods as new inventories are developed. The analysis suggests that users of regional emission data bases need to pay attention to the year and daily conditions that were used in developing any motor vehicle emissions data base.