The concentration of carbon monoxide is dropping in rural regions of the eastern United States, in keeping with trends observed at urban monitoring stations.

Hallock-Waters, K.A. . . . R.R. Dickerson, et al. 1999. Carbon monoxide in the U.S. Mid-Atlantic troposphere: Evidence for a decreasing trend. Geophysical Research Letters 26(Sept. 15).

Beaton, S.P., et al. 1995. On-road vehicle emissions: Regulations, costs and benefits. Environmental Science and Technology 268(May 19):991.

Monastersky, R. 1994. Atmospheric pollutant takes a nosedive. Science News 145(March 26):207.

Novelli, P.C., K.A. Masarie, and P.M. Lang. 1998. Distributions and recent changes of carbon monoxide in the lower troposphere. Journal of Geophysical Research 103(Aug. 20):19,015.

Raloff, J. 1995. Outdoor carbon monoxide: Risk to millions. Science News 148(Oct. 14):247.

The EPA’s National Air Quality and Emissions Trends Report can be found at http://www.epa.gov/oar/aqtrnd97, and the Office of Air and Radiation also offers a trends report at http://www.epa.gov/oar/aqtrnd97/brochure/co.html.

Russell R. Dickerson
University of Maryland, College Park
Department of Meteorology
College Park, MD 20742

Kristen A. Hallock-Waters
University of Maryland, College Park
Department of Chemistry and Biochemistry
College Park, MD 20742

Joseph Pinto
U.S. Environmental Protection Agency
USEPA Mailroom
MD-52
Research Triangle Park, NC 27711

Donald H. Stedman
University of Denver
Department of Chemistry and Biochemistry
Denver, CO 80208

From Science News, Vol. 156, No. 13, September 25, 1999, p. 198. Copyright © 1999, Science Service.