If you suffer from asthma, Lancaster County is a challenging place to live, according to the Asthma and Allergy Foundation of America.

The nonprofit consumer and patient organization ranked Lancaster County the 21st worst for living with the respiratory condition out of the 100 largest metropolitan areas in the United States.

Harrisburg was ranked the fifth “most challenging” place to live for asthma sufferers. Scranton was ninth; Allentown was 16th; and Pittsburgh was 23rd.

Atlanta was ranked the worst metro area in the nation for those with asthma.

The Washington-based group ranked the metropolitan areas based on 12 factors including prevalence of asthma, mortality from the condition, air quality, public smoking laws, medication usage and the number of asthma specialists in each metro area.

Lancaster County received worse than average marks for asthma prevalence, deaths from asthma, air quality, its public smoking laws and the number of asthma specialists serving the population.

The area got better than average marks for its poverty rate, the number of residents uninsured and the high number of asthmatics who must use inhalers and other “rescue” medications here.

A year ago, an environmental group, PennEnvironment, said the Lancaster County area had the fifth-worst soot problem in the U.S. for mid-sized cities.

Soot — fine and coarse particles in the air from power plants and vehicles — aggravate asthma conditions.

And in 2004, the county was ranked with the 23rd-worst smog problem by the American Lung Association. Smog, also known as ozone, comes largely from power plants and vehicles, and also can harm asthma sufferers.

However, last August, the state Department of Environmental Protection sought to have the county listed as in compliance with smog standards, saying there had been no ozone violations in Lancaster County for several years.

The AAFA said it does annual rankings of asthma hotspots to encourage asthma sufferers to work with their communities to improve local problems.

“The ranking gives us evidence of how problematic asthma is across the country,” said Dr. Derek Johnson, director of pediatric allergy at the Temple University Medical Center, in a AAFA press release.

“People just can’t move away from their asthma since every city in America has a variety of risk factors. Instead, people should work with an asthma specialist to make a good asthma management plan no matter where they live.”