The American Lung Assn.
of The Air
The American Lung
Association State of the Air 2011 report ranks the metropolitan areas
based on ozone and particle
pollution during 2007, 2008 and 2009. For particle pollution, we rank
separately the areas with high year-round (annual average) levels and high
short-term levels (24-hour) found in monitoring sites across the United States.
We take official data from the U.S. Environmental Protection Agency (EPA) to
compile the rankings. For more information about how we grade and rank cities,
go to Methodology.
The cities are ranked by the air quality in the most polluted county in the metropolitan
area. Click on the city name to open links to a chart of the trends for ozone
and year-round particle levels, as well as more information about air pollution
and the local Lung Association. Note that some cities rank high on one list and
donít show up on other lists because of the differences in their pollution
problems. Each city includes all the counties that form the economic and
transportation network that makes up the metropolitan area as defined by the
The cities on the cleanest cities lists for ozone and for short-term levels of
particle pollution had no days with unhealthy levels of ozone or particle
pollution. These lists are not ranked because all the cities earned the same
scores. The cities on the list of the cleanest for year-round particle
pollution levels are ranked by their average levels of particles, as calculated
by the EPA. Note that some cities are clean for one category, but not for