According to the Asthma and Allergy Foundation of America’s 2010 ranking, Knoxville is the worst allgery city to live in spring in America, followed by Louisville and Chattanooga. The factors that contribute to allerge including high concentration of grass, trees or weeds, wind, humidity, and air pollution.

Since pollen thrives in high humidity, you'd better to get far away from river basins if you have hay fever.