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Frequently Asked Questions about Ozone and Your Health

On hot, sunny summer days, ground level ozone can rise to unhealthy levels. Breathing ozone can trigger a variety of symptoms, including coughing, throat irritation, and chest pain. It is important to understand the health effects of ozone and the simple steps you can take to protect yourself.

How can ozone affect health?

Ozone affects the lungs and respiratory system in many ways. Exposure can lead to increased school or work absences, visits to doctors and emergency rooms, and hospital admissions. Research also indicates that ozone exposure can increase the risk of premature death from heart or lung disease.

Ozone can:

Irritate Your Respiratory System

You might start coughing, feel an irritation in your throat, or experience an uncomfortable sensation in your chest. These symptoms can last for a few hours after ozone exposure and may even become painful.

Reduce Lung Function

Lung function is the volume of air that you draw in when you take a full breath and the speed at which you are able to blow it out. This can make it more difficult for you to breathe as deeply and vigorously as you normally would, especially when exercising. If you are exercising or working outdoors, you may notice that you are taking more rapid and shallow breaths than normal. Reduced lung function can be a particular problem for outdoor workers, competitive athletes and others who exercise outdoors.

Aggravate Asthma Symptoms

When ozone levels are high, more asthmatics have attacks that require a doctor’s attention or the use of additional medication. Ozone makes people more sensitive to allergens, which are common triggers for asthma attacks. Asthmatics may also be more severely affected by ozone-induced respiratory irritation and reduced lung function than non-asthmatics.

Inflame and Damage the Lining of the Lung

Some scientists have compared ozone-caused lung damage to a sunburn. Ozone damages the cells that line the air spaces in the lung. Within a few days, the damaged cells are replaced and the old cells are shed–much in the way skin peels after a sunburn. If this kind of damage occurs repeatedly, it may lead to permanent damage to your lungs that could cause a lower quality of life.

Cause Permanent Lung Damage

Repeated short-term ozone damage to children’s developing lungs may lead to reduced lung function as an adult. In adults, ozone exposure may accelerate the natural decline in lung function that occurs with age.

Who is at risk?

Roughly one out of three people in the U.S. is at risk of experiencing ozone-related health effects. As concentrations of ground level ozone increase, both the number of people and the seriousness of the health effects increase. People who are particularly sensitive to ozone include:

  • people with lung diseases such as chronic bronchitis, emphysema, and asthma;
  • children, because they often play outdoors when ozone levels are high, are more likely to have asthma, and take in a greater proportion of air than adults when they breathe;
  • older adults;
  • active people of all ages who work or exercise vigorously outdoors; and,
  • healthy people who happen to be sensitive to ozone.

How can you avoid unhealthy exposure?

People are generally exposed to ozone when they are outdoors during high ozone periods. The rate of exposure for a given individual is related to the concentration of ozone in the surrounding air and the amount of air the individual is breathing per minute. Consequently, increased physical exertion during outdoor activities increases a person’s rate of ozone exposure. People with the greatest exposure are those who exercise outdoors for long periods of time when ozone concentrations are high. Since people breathe more deeply during exercise, ozone penetrates deeper into the respiratory tract, increasing the possibility of adverse health effects. People with the lowest exposure are those who spend most of the day in an air-conditioned building with little air turnover. You can protect your health by:

  • Paying attention to symptoms such as coughing, chest pain with a deep breath, chest tightness, and shortness of breath and reducing your exposure.
  • Rescheduling outdoor physical activities to times of day when ozone levels are lower, generally before noon and after 6:00 p.m.
  • Reducing the time you are active outdoors.
  • Substituting less intense activities for those that require greater exertion, such as walking instead of jogging.
  • Creating an ozone action plan if you have asthma or other chronic respiratory conditions and following it carefully when ozone levels are elevated

Because fitness levels vary widely among individuals, moderate exertion for one person may be heavy exertion for another person. No matter how fit you are, cutting back on the level or duration of exertion when ozone levels are high will help protect you from ozone’s harmful effects.

How can you know when ozone levels are unhealthy?

Checking local air quality using the Air Quality Index (AQI) is as easy as checking the weather forecast. The AQI is a simple color-coded scale that corresponds to six different levels of health concern. For example, yellow means “moderate” conditions and red means “unhealthy” conditions. This color scheme can help you know at a glance if ozone is reaching unhealthy levels and you need to take steps to reduce your exposure. You can find daily ozone forecasts and real-time ozone conditions at AirNow.

Source: U.S. Environmental Protection Agency

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