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Clinical Scenario 3
A 32-year-old man comes in to the office with concerns about the exercise program he recently started. After discussing problems with a sore knee, he describes an episode of coughing and chest discomfort - like a burning sensation in the airways - that occurred recently. Although it was a Code Orange day for ozone, he decided to go for a run. Shortly after leaving his home, the man started coughing, so he slowed to a brisk walk. Even at that pace, he felt a burning sensation in his chest made worse by taking a deep breath. So he went home and rested on the couch. In about an hour the pain subsided. He asks you, "Can air pollution cause burning like that?"


1. Health effects. Short-term ozone exposure can cause cough, pain or discomfort on deep inspiration, and shortness of breath during and immediately following exposure in otherwise healthy people. These symptoms are reversible and usually disappear within several hours of terminating exposure. There is some evidence suggesting that long-term exposure to high ozone levels may have long-term effects, but this is preliminary, and there is no information as to whether an acutely sensitive individual would be at more risk of a long-term effect. The limited data available indicate that the degree of sensitivity as measured by symptoms (e.g., cough) is not related to the degree of sensitivity as measured by the reactions in the respiratory tract (e.g., reversible respiratory epithelial cell injury and inflammation) that also accompany ozone exposure.

2. Inter-individual variability. Individuals vary in their responsiveness to ozone. This individual appears to be a more responsive individual. Although there is variability in responsiveness within an age group, in general, young adults (teens to thirties) appear to be more responsive than older adults (fifties to eighties), though children do not appear to be more sensitive than young adults with regard to respiratory symptoms.

3. Symptoms. Also note that the symptoms of cough and shortness of breath during exercise are consistent with exercise induced asthma, and although this person claims to be nonasthmatic, this should be considered in the differential diagnosis

4. Exposure reduction. Sensitive individuals can avoid or reduce symptoms by reducing the inhaled dose of ozone (the product of concentration, minute ventilation, and duration of exposure) by reducing time spent outdoors or reducing the level or duration of outdoor activity during the times of day that ozone levels tend to be highest.