The good and the bad about ozone

Q. I don't get it. Is ozone a good thing or a bad thing?

Ozone, a gas, is a form of oxygen. It is created when an electric spark or ultraviolet light passes through air, or when pollutants react chemically with sunlight.

Beneficial ozone is in the upper atmosphere, 10 to 30 miles above the surface of the Earth. It protects us from the sun's ultraviolet rays. Too much of these rays may increase the risk of skin cancer, cataracts and problems with our immune systems. Part of the good ozone layer has been destroyed by man-made chemicals.

Detrimental ozone is at ground level and is the main component of smog. This bad ozone is horrible for your respiratory system. Ozone may aggravate chronic lung diseases such as emphysema and bronchitis, and reduce the immune system's ability to fight off bacterial infections in the respiratory system.

Seniors and children are especially vulnerable to ozone pollution. Those with asthma and nasal inflammations seem to be more sensitive to pollutants.

Active children are at highest risk from ozone exposure because they spend a lot of time playing outdoors. Obviously, adults who work and play outdoors are at higher risk than indoor types.

Ozone can make you cough, suffer from throat irritation and experience an uncomfortable sensation in your chest. This gas can also make it more difficult to breathe deeply.

People who experience high ozone levels may discover that their initial symptoms disappear after a while. However, ozone continues to cause lung damage even when there are no symptoms.

Studies done in the U.S. reported that ozone with concentrated ambient fine particles can cause a significant increase in blood pressure. The studies also found that increased levels of ambient sulfate and ozone may increase the risk of heart arrhythmia in older people.

Seniors with respiratory problems should check the news and highway signs for reports of high ozone levels.

The Air Quality Index reports levels of ozone and other common pollutants in the air. The higher the AQI value, the greater the health concern.

The following guide about AQI ratings is from the U.S. Environmental Protection Agency:

• Good. The AQI value for your community is between 0 and 50. Air quality is satisfactory and poses little or no health risk.

• Moderate. The AQI is between 51 and 100. Air quality is acceptable; however, pollution in this range may pose a moderate health concern for a very small number of individuals. People who are unusually sensitive to ozone or particle pollution may experience respiratory symptoms.

• Unhealthy for Sensitive Groups. When AQI values are between 101 and 150, members of sensitive groups may experience health effects, but the general public is unlikely to be affected.

• 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 feel serious health effects.