Spring, heat mean start of ozone warnings

"If inhaled, ozone causes breathing and airway problems for asthma sufferers and smokers with chronic obstructive pulmonary disease (COPD). People can have difficulty breathing and sometimes experience severe chest pains. For some sufferers, immediate hospital attention and treatment are required," says Dr. Nick Hanania, director, Adult Asthma Clinic and Pulmonary Diagnostic Laboratory, Ben Taub General Hospital, part of the Harris County Hospital District.

Houston, the nation's fourth largest city, has some of the highest concentration of ozone pollution.

Created through a combination of pollutants from cars, industrial sites and the area's intense heat, ozone is a dangerous gas. However, this ozone gas should not be confused with the protective atmospheric layer of ozone shielding earth from the sun's harmful rays. Ground-level ozone pollution can be seen as smog from miles away and sometimes appears as a hazy shimmer around a downtown skyline, says Hanania, also associate professor, Section of Pulmonary, Critical Care and Sleep Medicine, Baylor College of Medicine.

People susceptible to ozone are children who normally spend a lot of time outdoors during the summer, active adults who work or exercise outdoors, people with asthma or other respiratory problems and others who have unknown reactions to ozone.

Ozone can cause the following symptoms:

• Cough, throat irritation and uncomfortable sensation in the chest

• Reduced lung function and the inability to breathe normally

• Inflamed and damaged cells in the lining of the lungs

• Difficulty fighting off lung infections

Not all people show symptoms. In some, lung damage can occur without any noticeable signs. In others, lung damage can continue to occur even after symptoms disappear. When levels are high, people at risk should take these simple precautions:

• Stay indoors and in air-conditioned comfort, as much as possible

• Limit outside activities to the early morning hours or after sunset

• Don't exercise or work outdoors when ozone levels tend to be highest

•Stay away from high-vehicular traffic areas and avoid exercising near these areas

Ozone is not confined to industrial or heavy car traffic areas of town. Ozone gas can be moved about by wind and sometimes lingers in areas and trap itself inside houses. In houses without air conditioning, ozone can come in through open windows and doors. Fans placed in windows for cooling can pull in ozone into houses.

"Public ozone alerts are important because they help people stay safe and healthy. Depending on the levels of ozone in the air, these alerts can be life-saving for some people. The best thing is to be in a place with central air or air conditioning," Hanania adds.

If symptoms and breathing problems occur, seek immediate medical attention through a primary care physician or an emergency center. For more information on ozone warnings and forecasts, visit the U.S. Environmental Protection Agency.