Protection From Ozone-Related Respiratory Problems Only a Fresh Smell Away

People are capable of smelling ozone trouble, if they just use their noses.

Learning to recognize what ozone smells like enables people to make educated decisions about how much time they spend outside. Ozone exposure can be especially harmful to active children and adults, those with respiratory diseases and the elderly.

After monitoring equipment performs high-tech tests on outdoor air, if needed, alerts are issued to notify Houston-Galveston area residents of unhealthy ozone levels.

"Ozone is the fresh smell you can detect during and after a thunderstorm," says Gene McMullen, Houston Department of Health and Human Services' Bureau of Air Quality Control assistant bureau chief. "Office machines such as copiers and laser printers generate electric fields that also produce a small amount of ozone that you can easily smell."

Ozone is a gas composed of three atoms of oxygen. It occurs naturally in the Earth's atmosphere and creates a shield against the sun's ultraviolet rays. It also forms at ground level when emissions by cars, power plants, refineries, chemical plants and other sources react chemically with sunlight.

Unhealthy levels of ground-level ozone typically form in the afternoon during the hot summer months, when sunny days with high temperatures and low wind speeds are more common, says McMullen.

McMullen says recognizing ozone gives people a head start since it takes an hour and-a-half to two hours for information on pollution levels to become available through the Internet or the news media.

"Ozone can cause or aggravate respiratory health problems, which may result in emergency room visits or hospital admissions during, or a few days after, high levels of exposure," says Dr. Nick Hanania, a Baylor College of Medicine pulmonologist. Dr. Hanania is conducting a study exploring the correlation between pollutants and emergency room visits to Ben Taub General Hospital by adult asthmatics.

Dr. Hanania says ozone-related respiratory problems include:

* Irritation of the respiratory system. Symptoms include coughing, throat irritation or an uncomfortable sensation in the chest; they may last a few hours and become painful.

* A reduction in lung function. Ozone can make it more difficult to breathe deeply and vigorously. If exercising or working outside, people may notice they are taking more rapid and shallow breaths than normal, a problem for outdoor workers.

* Exacerbation of asthma. Ozone makes people more sensitive to allergens. When the pollutant reaches high levels, more asthmatics have attacks, requiring a doctor's attention, or use of additional medication. Asthmatics are also severely affected by the reduced lung function and irritation that ozone causes in the respiratory system.

* Inflammation and damage of lung tissue. Ozone damages the cells that line the air spaces in the lung. Affected cells are replaced after a few days, but if damage occurs repeatedly, the lung may change permanently and possibly cause long-term health effects and lower quality of life.

Dr. Hanania, who is also director of Baylor's Asthma Clinical Research Center, says groups most at risk to harmful ozone exposure are children and adults who engage in vigorous outdoor activities, people with respiratory diseases such as asthma and those with unusual susceptibility to ozone.

Information on local ozone levels is available from the Bureau of Air Quality Control by calling 713-640-4358. The recorded statement provides callers the daily air quality index, which is divided by Environmental Protection Agency into five categories: good, moderate, unhealthy for sensitive groups, unhealthy and very unhealthy.

If the index falls in the good category, no health impacts are expected. The moderate category warns unusually sensitive people to consider limiting prolonged outdoor exertion. The unhealthy for sensitive groups category alerts active children and adults and people with respiratory disease to limit prolonged exertion. The unhealthy and very unhealthy levels notify everyone, especially active children and adults and people with respiratory disease, to limit prolonged exertion.

The Bureau of Air Quality Control is responsible for air quality issues within Houston's city limits. It enforces federal and state air pollution regulations, operates and maintains an ambient air-monitoring network and enforces Houston's air pollution registration ordinance.

Information on ozone watches and warnings are available on the Houston Department of Health and Human Services Web site, www.ci.houston.tx.us/departme/health/environmental.html. An ozone watch indicates conditions likely to form high levels of ozone, while a warning indicates that levels have exceeded the federal health standard.

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©2006 Texas Medical Center

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