This document presents the most recent estimates of national and regional emissions of the criteria air pollutants, lead, sulfur dioxide, and particulate matter. The emission trends are the net effect of many factors, including changes in the nation's economy and in industrial activity, technology, consumption of fuels, traffic, and other activities that cause air pollution. The trends also reflect changes in emissions as a result of air pollution regulations and emission controls. The emissions of each pollutant are estimated for many different source categories, which collectively account for all anthropogenic emissions. The report presents the total emissions from all 50 States and from each EPA Region in the country. Also included this year is coverage of biogenic, greenhouse gases, toxics, and global emissions. Estimates are included from 1900 to 1992. Preliminary estimates are presented for the years 1990 through 1992 and will be finalized in next year's report.

Cover title. Prepared in part by E.H. Pechan & Associates. Project officer: Sharon Nizich. "October 1993." Includes bibliographical references (pages 9-1-9-7).