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Clinical Scenario 2
During the well-child physical exam of a 3-year-old boy, the mother indicates that she is starting back to work and, for four days a week, she will be leaving her son in a local day care. She has a few questions about the day care situation she has found for him. One of the questions concerns outdoor playtime on days with high levels of air pollution. It is the daycare's policy to let the children go out for an hour in the morning on Code Orange or Red air quality days. The mother asks you, "Shouldn't they keep him in on days when air pollution levels are high?"

1. Long-term health effects. Although there is no conclusive answer as to whether long-term exposure to ozone can result in serious health effects in people without asthma, there is some evidence suggesting that long-term exposure may predispose one to development of new asthma and may interfere with the postnatal growth and development of the respiratory system. These potential effects may be related to the reversible respiratory epithelial injury and inflammation accompanying short-term exposure. On the other hand, long-term ozone exposure does not appear to account for a large part of the asthma or other respiratory disease in the population living in some cites of the United States with high ozone levels. Research in these areas will hopefully help quantify any health risks of long-term exposure and identify the determinants of exposure most responsible for any such effects.
2. Benefits of exercise. It is well known that active exercise promotes better health for children and adults. The well-documented benefits of exercise should not be given up as one tries to avoid potential health effects of ozone exposure. If one chooses to reduce outdoor activity when ozone levels are high, indoor activity should be increased on those days or outdoor activity should be increased at times of the day or on other days when pollution levels are lower.
3. Balanced response. Given the known health benefits of exercise, the inevitable scheduling of outdoor activities that may be important to one or one's children during high ozone periods, and the uncertainties of ozone health effects, it is hard to argue that one should never exercise outdoors on high ozone days. On the other hand, it would be prudent to minimize cumulative exposure when possible by reducing exposure on days when outdoor ozone levels are high (Code Orange or Red days) without reducing the overall level of physical activity. The inhaled dose of ozone (the product of concentration, minute ventilation, and duration of exposure) can be reduced on heavily polluted days by reducing the amount of time spent outdoors or reducing the level and duration of outdoor activity during the times of day that ozone levels tend to be highest in your area. In areas where ozone levels are routinely high, one might develop a schedule for outdoor activities that avoids the worst times of day and that allows for either rescheduling activities or reducing activity levels on bad days.