Exercise in Air Pollution
It's healthful to exercise and harmful to breathe polluted
air. Many people wonder if they will do more harm than good by
exercising on days when the air is heavily polluted. The worst
time for pollution is when clouds cover the sky and automobiles
fill the roads. Automobile exhaust fumes are the principal source
of air pollution in most cities, and overlying clouds increase
pollution. Usually the sun’s rays heat the ground to warm air
closest to the ground. Hot air rises, taking large amounts of
pollutants skyward. On air inversion days, the clouds prevent the
sun's rays from getting through to the ground, so the air near the
ground is not heated, remains colder and doesn't rise, causing
the air with its pollutants to remain close to the ground.
Air pollutants such as carbon monoxide, ozone, carbon
dioxide, and sulfur dioxide can damage your lungs. When you
exercise, you breathe more deeply and more frequently so that
you breathe in more pollutants. However, you don't retain more
pollution. Bicycle riders in rush hour downtown Washington
traffic breathe in more carbon monoxide than car riders do, but
have lower blood levels of carbon monoxide. So keep exercising,
but if possible, try to avoid heavily trafficked streets, and
exercise before the heavy morning traffic peak or at least two
hours after the evening rush hour ends.
February 1, 2006