KNOXVILLE, Tenn. (WVLT) -- If you suffer from asthma, Knoxville is one of the most challenging places you can live. Rankings by the Asthma and Allergy Foundation of America put Knoxville at number four among the worst cities for people with Asthma.

"We live in the Tennessee Valley, and a valley tends to trap pollutants," said Dr. Elise Schriver, a pulmonary physician at the University of Tennessee Medical Center's Heart Lung Vascular Center.

That pollution, pollen problems, and allowing smoking in public places has led the AAFA to rank Knoxville the fourth worst city in the nation for asthmatics.

"We see a lot of asthma. It's very common," said Dr. Schriver. "A lot but not all of asthma is due to allergies and we live in a very moist area, where a lot of plants, pollens and molds flourish."

"Allergy season, coming up, will affect it," said Traci Connatser of Knoxville. Connatser has suffered from asthma for nearly a decade. "The last couple of weeks I can tell that I started wheezing more."

Connatser takes year-round allergy medicine, and uses an inhaler when she has asthma symptoms. "I can't control the allergy season and stuff like that. I can just control that by taking medication."

Dr. Schriver says using symptom relievers properly, and controller medicines if necessary, is the best way to treat your asthma, no matter where you live. "It's a disease that you need to maintain control of, just as if you have diabetes or high blood pressure. You'll need to maintain control of it the rest of your life," she said.

Although some cities may have fewer environmental triggers, you can't escape your asthma by skipping town. "Once you have asthma, you've got asthma usually forever," said Dr. Schriver. "If you move away, you can't get away from your asthma."

The AAFA says there aren't any asthma-free cities, and one in five Americans is affected by asthma.

Richmond, Va. is the 2010 Asthma Capital. St. Louis is second, followed by Chattanooga. Minneapolis ranks best.