USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

6-4 Index of Key Air Pollutant Emissions from U.S. Transportation: 1990-2008

Tuesday, December 27, 2011

6-4 Index of Key Air Pollutant Emissions from U.S. Transportation: 1990-2008

Excel | CSV | Graphic Version

Index: 1990 = 1.0

Year Carbon monoxide Nitrogen oxide Volatile organic compounds PM-10; PM-2.5 Surfur dioxide Ammonia
1990 1.00 1.00 1.00 1.00 1.00 1.00 1.00
1991 0.95 0.99 0.94 0.96 0.95 0.93 1.09
1992 0.90 0.97 0.89 0.91 0.90 0.87 1.17
1993 0.86 0.96 0.83 0.87 0.85 0.80 1.26
1994 0.81 0.94 0.78 0.83 0.81 0.73 1.35
1995 0.76 0.93 0.72 0.79 0.76 0.67 1.43
1996 0.71 0.91 0.66 0.74 0.71 0.60 1.52
1997 0.69 0.92 0.64 0.71 0.67 0.60 1.71
1998 0.66 0.90 0.62 0.66 0.62 0.60 1.65
1999 0.62 0.87 0.61 0.62 0.57 0.60 1.72
2000 0.62 0.88 0.57 0.59 0.54 0.52 1.77
2001 0.58 0.81 0.53 0.55 0.49 0.49 1.79
2002 0.55 0.82 0.52 0.52 0.46 0.49 1.90
R2003 0.51 0.77 0.50 0.52 0.45 0.42 1.92
R2004 0.48 0.72 0.47 0.51 0.43 0.36 1.95
R2005 0.44 0.68 0.44 0.50 0.42 0.29 1.98
R2006 0.41 0.63 0.41 0.48 0.40 0.24 1.97
R2007 0.38 0.59 0.39 0.46 0.37 0.18 1.98
2008 0.35 0.54 0.36 0.44 0.34 0.13 U

Key: R = revised, PM-10 = airborne particulates of less than 10 microns, PM-2.5 = airborne particulates of less than 2.5 microns, U = unavailable.

Notes: The indexes are calculated using data on emissions from highway vehicles only. Particulate matters include PM without condensibles. 2003 data are revised except carbon monoxide, nitrogen oxide, surfur dioxide, and ammonia. 2004 data are revised except nitrogen oxide, sufur dioxide, and ammonia. 2005 data are revised except carbon monoxide, surfur dioxide, and ammonia. 2006 data are revised except carbon monoxide, volatile organic compounds, and ammonia. 2007 data revised except carbon monoxide, surfur dioxide, and ammonia.

Source: U.S. Environmental Protection Agency, Clearinghouse for Inventories and Emissions Factors (CHIEF), Current Emission Trends Summaries, available at http://www.epa.gov/ttn/chief/trends/index.html as of September 2009.