Much of the ozone pollution at high elevations in the mountains of Western North Carolina is transported by winds from other states. Symptoms of ozone exposure can include coughing, throat irritation, chest pain, rapid and shallow breathing, and asthma attacks. Emergency room visits for asthma have increased as much as 36 percent on high ozone days, according to some studies. High ozone levels can damage leaves on trees and crops, reducing growth rates and crop yields. Due to its reactive nature, ozone also can prematurely degrade and wear out rubber, paints and other materials.
Ozone is primarily a problem during the summer months, when heat and sunlight are more intense.
Ozone levels also vary on a daily basis. In most areas of North Carolina, ozone levels peak in the afternoon, when temperatures are higher, and then drop at night. In the mountains, however, ozone levels can remain high throughout the day and night at altitudes above 4,000 feet. You can prevent unhealthy ozone exposure by limiting outdoor work and exercise in the afternoons on high ozone days. Ozone levels generally are much lower in the mornings, so limit exposure by working and exercising outdoors before noon.