PITTSBURGH -- A recent study done by the American Lung Association ranks Pittsburgh as the worst city in the nation for air pollution.

However, Guillermo Cole of the Allegheny County Health Department, said, "The ranking is unfair and misleading."

Cole told Channel 11 News that the ALA based its ranking on a single air sample from a single site in Allegheny County. That site is the liberty monitor on top of South Allegheny High School, which is less than 3 miles from the Clairton coke works.

Cole said the ALA didn't use several other air quality samples -- from places like Lawrenceville, Moon and North Park -- which all met the national standard.

It's the second consecutive year that Pittsburgh was at the top of the list.

The city was also ranked second worst for year-round particle pollution, only behind Los Angeles.

The ALA said the rankings were based on monitors from the Environmental Protection Agency located throughout Allegheny County.