Ozone season in North Texas officially began on April 15, and while many think that the invisible gas with the funny name is all about the upper atmosphere, it can create perilous health conditions right here on the ground. Ozone is nothing more than a mutated form of the oxygen that keeps us alive. Instead of the regular two atoms in its molecule, it has three. In nature, the action of the sun’s radiation is why, but it’s complicated.

Nine counties have been classified by the U. S. Environmental Protection Agency (EPA) as having unhealthy concentrations of ozone: Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall and Tarrant.

Breathing air that contains ozone can reduce lung function and increase respiratory symptoms, aggravating asthma and other respiratory conditions. Ozone exposure also has been associated with increased susceptibility to respiratory infections, medication use by asthmatics, doctor visits and emergency department visits and hospital admissions. It may also contribute to premature death, especially in people with heart and lung disease. High ozone levels can also harm sensitive vegetation and ecosystems.

Inhaling ground-level ozone is especially dangerous for people that have asthma or respiratory problems, and they may experience increased frequency of asthma attacks and health care needs. Young children may also be at risk for developmental problems associated with ozone exposure. Asthma rates have more than doubled over the last 20 years. People without respiratory problems or asthma can also experience health effects from ozone exposure such as coughing, throat irritation, pain, burning or discomfort when taking a deep breath, chest tightening and shortness of breath.

There is an Air Quality Index that the government uses for reporting daily air quality levels. It’s color-coded to indicate how polluted the air is and how to protect your health. Green: good, no action necessary; Yellow: moderate, unusually sensitive people should consider limiting prolonged outdoor exertion; Orange; unhealthy for sensitive groups, active children/adults and people with respiratory disease or asthma should limit prolonged outdoor exertion; Red: unhealthy, active children/adults and people with respiratory disease or asthma should avoid prolonged outdoor exertion; everyone else, especially children, should limit outdoor exertion; Purple: very unhealthy, active children/adults and people with respiratory disease or asthma should avoid all prolonged outdoor exertion; everyone else, especially children, should limit prolonged outdoor exertion.

Nowadays, gas-burning vehicles cause half of all ozone-forming emissions. Other manmade emissions sources include cement and power plants, bakeries, paint shops, dry cleaners, vegetation and forest fires.

The North Central Texas Council of Governments and Regional Transportation Council have developed a list of the most ozone-producing activities for our region's air quality, and these are things that the public has at least some control over. The list includes driving gas-guzzlers, cold starts, hard accelerations, high speeds, low speeds, excessive idling, diesel engines and vehicle miles traveled. It’s simple: lots of cars equal lots of ozone.

For more information, visit AIRNow.gov.