Monday, March 17, 2008
The air we breathe
By A. Chris Gajilan
Senior Medical Producer
Could the air you breathe cause permanent damage to your health? That is one of the reasons marathon runner and world record holder Haile Gebrselassie has said he will not compete at the Beijing Olympics this summer. While the 34-year-old Ethiopian says he won't run the marathon, he has said that he hopes to run the 10,000 meter race. Gebrsealassie has exercise-induced asthma and is concerned that the longer marathon may cause permanent damage to his health.
Without a doubt, the air in Beijing is bad, but does it really have the potential to cause long-lasting damage in someone who would spend about a month on the ground? When I was there in the early 1990s, the air was thick and hazy. There was a layer of soot from the nearby coal-operated factories. Since then, Beijing has boomed economically, and cars and industries have sprung up everywhere. Today, one measure of air pollution is nearly double the safe limit levels according to Dr. Homer Boushey of the Health Effects Institute. Fine particulate matter, which is found in haze, smoke and dust, has been measured at levels close to 300 microns/cubic meter. The safe upper limit is 150 microns/cubic meter.
While Dr. Boushey says that it's unlikely that two to three weeks in Beijing will cause permanent damage to the lungs or the body, he does acknowledge that exercising in bad air exposes us to more pollutants. When we exercise heavily, we breathe mostly through the mouth, bypassing the body's first line of defense against pollution, the nose. Dr. Boushey points to one 1980s study of track meet results. Researchers found that the higher the levels of ozone on a particular competition day, the worse the winning times. He says there's a direct correlation between pollution conditions and athletic performance. In addition, there is a well-established relationship between ozone and particulate levels, and all cause mortality including heart attacks and respiratory disease. When air pollution levels are bad, there is a measurable increase in asthma attacks and emergency room visits due to respiratory problems. At greatest risk for health problems due to pollution are the elderly, children, those with chronic obstructive pulmonary disease, asthmatics and those with chronic bronchitis.
Are you concerned about air pollution? How do you think it affects human health?
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