CLEARING THE AIR: A REPORT ON EMISSION TRENDS IN SELECTED U.S. CITIES

This report presents data on the emissions inventories of volatile organic compounds (VOCs) and oxides of nitrogen (NOx) over the last 25 years in 10 cities scattered geographically throughout the country, as well as a forecast of those emissions inventories a decade from now. Furthermore, the emissions inventories are provided by source, allowing for a more complete view of the contributors to ozone and the relative effectiveness of past and future emission control efforts. Some key findings from this report are as follows: (1) While ground-level ozone continues to be a pervasive problem in many major U.S. cities, automobiles and light trucks are no longer the primary or even secondary cause of summertime ozone "smog" in the 10 cities studied. (2) Available emission inventories submitted to the Environmental Protection Agency by states indicate that autos and light trucks currently represent less than one-third of the overall emissions that lead to the ozone problems in these cities, compared to other polluters. (3) Although cars and light trucks continue to receive critical attention from the news media during ozone alerts, a more complete picture shows significant improvements in auto-related VOCs and NOx emissions over the past 35 years -- improvements unmatched by other sources of ozone -- with over a 90% reduction in VOCs and from 15% to 60% for NOx achieved by 2005, relative to 1970. (4) Analysis of local emission inventories from 1970 to 1996 projects that the role of stationary polluters in urban smog, such as refineries, manufacturing plants, and utilities has increased substantially at the same time that the role of the auto is declining. (5) Other mobile sources such as trucks, buses, planes, trains, and other utility and off-road vehicles show similar emission increases in these cities at a time when auto emissions are heading downward. (6) Continued tightening of Federal tailpipe emission standards, cutting hydrocarbon and NOx levels by 96% and 76% respectively over the past 25 years, is the single largest reason for the improvement in urban air quality -- more than offsetting the growth in vehicle miles traveled experienced in all 10 cities studied. (7) Programs such as new auto emission and light truck emission standards, periodic emission inspections and Reformulated Gasolines will be extremely effective in reducing auto-related ozone problems after 1996.

  • Corporate Authors:

    Energy and Environmental Analysis, Incorporated

    1655 North Fort Myer Drive
    Arlington, VA  United States  22209
  • Publication Date: 1994-9

Language

  • English

Media Info

  • Features: Figures; Tables;
  • Pagination: 34 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00672512
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jan 9 1995 12:00AM