Studies have shown that air pollution is related to the worsening of asthma symptoms. One study of young campers with moderate to severe asthma revealed they were 40 percent more likely to have acute asthma episodes on high pollution summer days than on days with average pollution levels.

Another recent study found that the number of daily hospital emergency room visits by older adults due to respiratory distress increased significantly as the air pollution levels in the summer months increased.

Ozone, one of the most common air pollutants, is created by a combination of sunlight, light winds, hydrocarbons from burned fuel and nitrogen oxide. Man-made air pollutants come from motor vehicles and power stations. This combination of elements can create a smog cloud. It is most common in cities where automobile concentration is greatest, and in the summer when the right conditions of sunlight and low winds occur. Under these conditions, we become literally surrounded by an ozone cloud.

Ozone triggers asthma because it is extremely irritating to the lungs and airways. It is well established that ozone concentration is directly related to asthma attacks, need for increased doses of asthma drugs, and emergency treatment for asthma. Throughout the United States, Ozone Action Days are declared when concentrations are highest. These declarations alert people with asthma to avoid the smog as much as possible by remaining in air-conditioned places and by taking other measures to avoid irritants and allergens. During Ozone Action Days, people with asthma should limit their time outdoors, especially from 11 a.m. to 8 p.m. They should stay in a well-ventilated-preferably air-conditioned-building. Most of all, do not exercise outdoors on Ozone Action Days. As always, use your peak flow meter and follow your asthma daily management and action plans.

The United States Environmental Protection Agency (EPA) defines air pollution as "any visible or invisible particle or gas found in the air that is not part of the natural composition of air." Air pollution is reported by the EPA using the Pollution Standard Index (PSI). PSI is reported as a percentage of the federal health standard for ozone. PSIs of 100 or more are dangerous for people with asthma and require special precautions and planning.

If you have asthma, you should also know that your symptoms can worsen even when ozone levels are moderate (PSI 50-100). You may still have to adjust your activities and medications.

Yes, but your concern should be appropriate to the type of environment in which you work. If you work with volatile solvents, sprayed substances, powders, or known carcinogens or allergens, your potential risks are high. Your employer is required to minimize them by meeting the standards of the Occupational Health and Safety Administration (OSHA), the EPA of the workplace.

Even if you work in what seems to be a chemical-free environment, you may still be exposed to air pollution. Older structures may contain mold spores or cockroaches, both powerful allergens. Dust mites are universal in indoor environments. And no matter how old the building, there may be hidden chemicals. New carpeting, for example, may release invisible but toxic fumes. Poorly filtered air handling systems may pour out allergens and irritants. If they are damp from handling humidity, they may actually breed mold spores. If tobacco smoking is permitted in the building, smoke may pollute your air you breathe. Reports of illness have become so repetitive at some work sites that they are said to have "Sick Building Syndrome."

Yes. The EPA and the American Lung Association include the home when declaring the indoor environment a "high priority public health risk." In all likelihood this is where you get your greatest exposure to allergens and irritants. They fall from out of the air and stick to surfaces like carpeting, upholstery and bedding, where their concentration grows. Surface allergens are far more numerous than airborne allergens.

Home is where you cook, eat, sleep, bathe, groom, relax and play with pets. In all of these activities your nose and mouth are dangerously close to, and may even be in direct contact with, the things that cause asthma symptoms. Soaps, cosmetics, cleaning solutions, fireplace or grill smoke, and hair spray may trigger an asthma episode as much as dander, pollinating flowers or dust mites. Neither the EPA nor OSHA regulates this environment. It is your personal responsibility to remove the causes of allergies, ventilate properly and perhaps install air filters.