Air Quality and Outdoor Exercise: Should You Worry?

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With the Olympic Games beginning this week and concern still lingering over the air quality in host city Beijing, I found myself thinking how lucky I am to have a lush, green, 600-acre park in my neighborhood where I can run and bike to my heart’s (and lungs’) content. Far from the expressway and shaded by trees, I’ve got to be safe from air pollution, right?
Not necessarily, says Norman H. Edelman, MD, chief medical officer of the American Lung Association. "Running in the park will protect you from carbon dioxide and some of the emission from cars, because those levels are higher on major roadways," he tells me. "But on a day with a poor-air-quality index, it’s not going to protect you from smog—it’s like a blanket that sits over the city, and it’s everywhere."
Air pollution, he explains, is usually grouped into two basic categories: ozone (otherwise known as smog), and particle pollution. Both have their own health risks, and both can encompass entire regions—not just hover in dark clouds near highways or smokestacks.
So what exactly is air pollution?
Ozone is formed when emissions from power plants, cars, factories, gas stations, and other sources come in contact with sunlight and heat—which is why smog levels are typically higher in the muggy months of May through October.
Particle pollution, called particulate matter or PM, can include solids such as dust, ash, soot, or liquid aerosols and particles too tiny to see. This type of pollution is heaviest near roadways, but can be present everywhere; it comes from auto exhaust, fuel, burning wood or trash (as evident during the recent California wildfires), cigarette smoke, and other sources.
What are the health risks?
When you breathe in ozone, it irritates your lungs—giving you something like a "sunburn" internally, Dr. Edelman says. This can cause shortness of breath, chest pain, wheezing and coughing, increased susceptibility to respiratory infections and asthma attacks, and inflammation of the lungs and airways.
Particulate matter—especially tiny, microscopic particles—can get deep into the lungs and can also cause irritation and inflammation. In addition, it can increase your long-term risk of lung cancer and heart disease. When EPA scientists analyzed air quality in just nine cities (Detroit, Los Angeles, Philadelphia, Pittsburgh, St. Louis, Boston, Phoenix, Seattle, and San José), they estimated that more than 4,700 premature deaths would occur each year, even if those cities met the current government standards for particulate matter.
If you’re exercising strenuously, you could be breathing in up to 20 times as much oxygen and pollution as you normally would (and if you breathe through your mouth, it bypasses your body’s natural nasal filter). As an athlete using 100% of your available lung function, you’re going to notice very quickly if that function is impaired—especially if you’re running long distances or breathing heavily for an extended period of time.
What can you do?
Luckily, the EPA monitors both types of air pollution, and you can find alerts for your area on its website, Airnow.gov. You can even have smog alerts emailed to you.
Experts suggest that you exercise indoors on days with poor-air-quality alerts, and use common sense at other times as well. Run in the mornings or in the evenings when temperatures and ozone levels are lower, and avoid congested streets and high-traffic areas (high levels of emission particles can linger up to 50 feet from the roadway). People with exercise-induced asthma or other health conditions should take extra precautions, and pay close attention to how specific times and places may affect their breathing.
We certainly don’t have the problem that China has, and pollution shouldn’t keep us from getting the benefits of outdoor exercise. But we should still be mindful of the days when air-quality levels are questionable, and take advantage of those which are still safe.
By Amanda MacMillan

source:www.healthnews.com