The 2008 Summer Olympics start today in Beijing, China. Central Texans will be watching along with the rest of the world. Most of the pre-games news has focused on the pollution problem in and around Beijing and how the athletes will be able to compete. This controversial topic does not just pertain to elite athletes and large metropolitan cities. Wherever there is the combination of cars, manufacturing, hot weather and at times unfortunate geography, there is the need to monitor the conditions on a daily basis if you spend time outdoors and especially if you exercise outdoors.

Many people go by the adage, "I have to see it to believe it." Well guess what? You can see the pollution in some cases but not all. We have seen the pollution Beijing is experiencing. You can see the pollution when you fly into a major metropolitan city if the conditions are right. And on local Ozone Action Days we can see the haze that seems to blanket downtown Austin in a fog.

Although Central Texas certainly doesn't compare to Beijing in terms of air pollution, outdoor exercising during one of the region's Ozone Action Days is not recommended. If you're using the Ozone Action Day alert or the hazy downtown visual as your guide of whether or not to exercise, you may want to use a more scientific means.

API versus AQI

The Texas Commission On Environmental Quality (TCEQ) uses a Air Quality Index formulated by the U.S.Environmental Protection Agency (EPA). The AQI is a daily means of reporting about air quality and the focus is how clean or dirty the air is and if there are any associated health concerns. Based on five major air pollutants regulated by the Clean Air Act, ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide are monitored and factored into the index. According to the TCEQ, Ground-level ozone and airborne particles are the two pollutants that pose the greatest threat to human health in this country.

• "Good" The AQI value for your community is between 0 and 50. Air quality is considered satisfactory, and air pollution poses little or no risk.
  
  
• "Moderate" The AQI for your community is between 51 and 100. Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people. For example, people who are unusually sensitive to ozone may experience respiratory symptoms.
  
  
• "Unhealthy for Sensitive Groups" When AQI values are between 101 and 150, members of sensitive groups may experience health effects. This means they are likely to be affected at lower levels than the general public. For example, people with lung disease, including asthma, are at greater risk from exposure to ozone, while people with either lung disease or heart disease are at greater risk from exposure to particle pollution. The general public is not likely to be affected when the AQI is in this range.
  
  
• "Unhealthy" Everyone may begin to experience health effects when AQI values are between 151 and 200. Members of sensitive groups may experience more serious health effects.
  
  
• "Very Unhealthy" AQI values between 201 and 300 trigger a health alert, meaning everyone may experience more serious health effects.
  
  
• "Hazardous" AQI values over 300 trigger health warnings of emergency conditions. The entire population is more likely to be affected.
  
  

In a nutshell, AQI values below 100 are generally thought of as satisfactory. When AQI values are above 100, air quality is considered to be unhealthy-at first for certain sensitive groups of people, then for everyone as AQI values get higher. If you're reading or watching Air Pollution Index (API) figures monitored in Beijing you can't correlate one to the other.

"The API and AQI are not apple to apples," says Andrea Morrow, TCEQ Spokesperson. "The API measures takes into consideration PM10 readings (sand and large particles). Except for the station in El Paso, we don't monitor PM10 around Texas. Occasionally, when the Saharan dust comes across the ocean and makes it's way to Texas, you'll see some warnings."

The Ministry of Environmental Protection, The People's Republic of China publishes API readings for its cities. If you're following the Olympics and the conditions the athletes are competing in, an API pollution reading below 50 is classed as "excellent," 51 to 100 "fairly good," 101 to 200 "slightly polluted," 201 to 300 "poor" and over 301 is "hazardous," according to the Beijing Municipal Bureau of Environmental Protection.

Health Concerns?

About 20.5 million people in the US have been diagnosed with asthma, with at least 6.2 million of them children under the age of 18. Asthma is the third ranking cause of childhood hospitalizations under the age of 15.

Asthma is a chronic, inflammatory disease in which the airways become sensitive to allergens (any substance that triggers an allergic reaction). Several things happen to the airways when a person is exposed to certain triggers:

• The lining of the airways become swollen and inflamed.
• The muscles that surround the airways tighten.
• The production of mucus in increased, leading to mucus plugs.

All of these factors will cause the airways to narrow, thus making it difficult for air to go in and out of your lungs, causing the symptoms of asthma. Ozone can aggravate asthma. Ozone makes people more sensitive to allergens, which are the most common triggers for asthma attacks.

• Ozone can irritate the respiratory system.
• Ozone can reduce lung function. When scientists refer to "lung function," they mean the volume of air that you draw in when you take a full breath and the speed at which you are able to blow it out. Ozone can make it more difficult for you to breathe as deeply and vigorously as you normally would. When this happens, you may notice that breathing starts to feel uncomfortable. If you are exercising or working outdoors, you may notice that you are taking more rapid and shallow breaths than normal. Reduced lung function can be a particular problem for outdoor workers, competitive athletes, and other people who exercise outdoors.
• Ozone can inflame and damage the lining of the lung.
• Scientists suspect that ozone may have other effects on people's health. Ozone may aggravate chronic lung diseases, such as emphysema and bronchitis. Also, studies in animals suggest that ozone may reduce the immune system's ability to fight off bacterial infections in the respiratory system.

More information about mindful eating can be found at the Asthma Services section of the Dell Children's Medical Center of Central Texas Web site.

Best Practices

You don't have to wear a mask when outdoors. You should be cognizant of the pollution forecast for the day and the times of the day that may make breathing more difficult for exercise. Here are some other tips to think about.

• Exercise when the levels are at their lowest. This generally occurs in the early morning for Central Texas. Levels are highest between noon and 6 p.m.
• Be flexible with your schedule. Monitor the readings on the Web site and plan accordingly.
• Throughout ozone season (April 1st October 31st), the CLEAN AIR Force offers a free notification service to participants by email when an Ozone Action Day is forecast for the following day. Sign up so you can make sure you're notified when conditions will be less than optimum.
• Keep a workout bag with gym clothing in your car or at the office and exercise indoors on the days when the levels are too high.
• Find a gym that sells one day passes.
• Sign up for an indoor yoga or Pilates session. We could all use more flexibility.

Links

City of Austin Air Quality Program
Ministry of Environmental Protection, The People's Republic of China API Readings
TCEQ Ozone Warning Status
TCEQ Map of Current Ozone Levels - State
TCEQ Austin Area AQI Readings
TCEQ Ozone Action Day Forecasts