West Side Cities Improve Air Quality

Seattle, Tacoma and Portland are among the top 10 cities nationwide when it comes to improved air quality over the past decade, a transportation research group said Monday.

The Road Information Program analyzed data from the U.S. Environmental Protection Agency in reaching its conclusions. It compared the average number of poor air quality days between 1986 to 1988 with those between 1993 to 1995 in urban areas with populations of more than 500,000.

Five areas - Seattle, Buffalo, Raleigh-Durham-Chapel Hill, Miami, and Tucson - had no poor air-quality days in the 1993-1995 period, resulting in a 100 percent improvement from the mid-1980s. Tacoma had one poor day from 1993-1995, and Portland had two.

By comparison, Seattle had an annual average of 15.67 poor days in the 1986-1988 period, Tacoma had an average 7.33, and Portland had an average 8.33.

The Road Information Program, a non-profit transportation industry group, attributed the improvement in air quality to reduced vehicle emissions during the period.