They include children, asthmatics, those with heart and lung diseases and elderly people. But anyone who exercises outdoors may be affected, including athletes, fitness enthusiasts, cyclists, outdoor workers and coaches. We breathe more air during exercise or strenuous work. We draw air more deeply into the lungs. And when we exercise heavily, we breathe mostly through the mouth, bypassing the body's first line of defense against pollution, the nose.
Children are especially susceptible to the effects of smog.
They spend significantly more time outdoors, especially in the summertime, when ozone levels are the highest. National statistics show that children on average spend 50 percent more time outdoors than adults. In addition, children have a higher breathing rate than adults relative to their body weight and lung surface area. This results in their getting a greater dose of pollution. Active children are the group at highest risk from ozone exposure because they often spend a large part of the summer playing outdoors.