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How ozone affects the air you breathe

Created date

July 5th, 2010

Inhale . . . exhale . . . inhale . . . exhale. Do you know what you re breathing? In 2006, ' almost a quarter ' of people age 65-plus lived in counties with unhealthy ozone levels, and 21% lived in counties where fine particle matter exceeded national standards.

Understanding ozone

When sunlight reacts with the smoke and gas from burning fossil fuels like petroleum, coal, or natural gas, ground-level ozone forms. According to the Centers for Disease Control, breathing ozone can worsen asthma, bronchitis, and emphysema. A recent study from the Harvard School of Public Health found death rates tended to rise on days when ozone pollution increased. Out of 2.7 million deaths across 48 U.S. cities, older adults and people with atrial fibrillation (a heart disorder) were at increased risk. "Ozone gets into your air passages, and it causes the lining of these areas to swell," says Norman H. Edelman, M.D., chief medical officer for the American Lung Association. "It s like getting a sunburn on your lungs. You may feel a tightness in your chest, have difficulty breathing, your eyes may tear, or your nose may be stuffed."

Pointing out particles

While ozone occurs more during warm summer months (between May and October), particle pollution occurs year-round. Particle pollution, or particulate matter (PM), is a complex mixture of small particles and liquid droplets. A major source comes from the burning of fuel in woodstoves, diesel trucks and buses, and coal-fired power plants. "The most dangerous kinds of particulates are very fine and get deep in the lungs," says Edelman. According to the American Lung Association, short-term increases of particle pollution (for hours or days) have been linked to death from respiratory and cardiovascular causes, including stroke, and increased numbers of heart attacks. "The cardiovascular effects of air pollution probably have the greatest impact on the health of older adults," says Sykes. "While our initial concerns about PM were focused on respiratory function, the data have shown that inhalation of PM into the lungs triggers a cascade of events that result in effects elsewhere in the body, most notably in the cardiovascular system." On days with high levels of particle pollution, one study found adults living with diabetes experienced a decrease in the ability of their blood vessels to control blood flow. "Decreased blood flow has been associated with an increase in the risk of heart attack, stroke, and other health problems," says Sykes. Recent data from a four-year study of 11.5 million Medicare enrollees showed that small increases in fine particle pollution resulted in increased hospital admissions for heart and vascular disease, heart failure, and chronic obstructive pulmonary disease. Participants over 75 years of age experienced the greatest increase in admissions for heart problems.

What you can do

You may not be able to see ozone or PM, but it s definitely there. That s why you should check the Air Quality Index (AQI) each day. The AQI has six levels to signal how clean the air is. Each level is a different color. You may have seen this index in your newspaper or in a weather report. Find it online at When the AQI shows unhealthy conditions, you should change your behavior. "When it s in the orange category, if you are in a sensitive group we recommend you do one of three things: move the time of the outdoor activity to a time when air quality is better, reduce the time you spend outdoors, or decrease your exertion level. Those will reduce your exposure," says Susan Stone, environmental health scientist with the U.S. Environmental Protection Agency. The harder you exercise, the more air you take in. When the AQI reaches orange, limit your outdoor activities (including things like gardening) to the early morning or wait until after sunset. You can also try walking indoors in a shopping mall or gym or use indoor exercise equipment. Even on days when the AQI shows healthy levels, avoid exercising near high traffic areas where particle pollution is more prevalent. Instead, walk or jog away from main roads. Everyone has different sensitivities to air quality, Stone explains. "People should try to figure out where they are on the scale. One thing people say is, I didn t realize I was sensitive to ozone, but now that I ve been looking at the AQI forecast, I ve noticed that when it hits a certain level, I might have some symptoms. " Follow the above tips from the pros, and you re sure to breathe easier.

Take a deep breath?

The Air Quality Index forecasts the current air quality. "Sensitive groups" can refer to older adults, children, individuals with respiratory disease such as asthma or heart disease, and individuals who are active outdoors.

Levels of health concern and their meaning

Good:Air quality is considered satisfactory, and air pollution poses little or no risk. Moderate:Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution. Unhealthy for sensitive groups:Members of sensitive groups may experience health effects. The general public is not likely to be affected. Unhealthy:Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects. Very unhealthy:Health alert-everyone may experience more serious health effects. Hazardous:Health warnings of emergency conditions. The entire population is more likely to be affected.