America's 25 Most Ozone-Polluted
Metropolitan Areas, 2006
Ozone acts as a powerful respiratory irritant at the levels
frequently found in most of the nation's urban areas during summer
months. Symptoms include shortness of breath, chest pain when inhaling
deeply, wheezing, and coughing. A study of a sample of longtime
residents of Los Angeles, which has the highest and most frequent ozone
problem in the nation, found that the group had a higher-than-expected
loss of lung function over time.