Ozone Exposure May Lead To Heart Attacks

Ozone, or trioxygen, is a naturally occurring gas present in the atmosphere. It is mostly concentrated in the region known as the ozone layer, located between 6 and 30 miles above the earth’s surface. The ozone layer filters out harmful ultraviolet rays, protecting life on the planet.

For several years, human activities have produced ozone-depleting substances, such as chlorofluorocarbons (CFCs), threatening the vital protective layer. This prompted the international community to come up with changes regarding emissions of harmful substances. Current trends show the ozone layer is expected to recover in the next few decades.

However, at ground level, ozone is a dangerous air pollutant. The gas can affect the cardiovascular system, and may even be lethal. Now, a new study reveals that even a short-term exposure to the gas can do its damage.

Low level ozone is formed when sunlight reacts with hydrocarbons and nitrogen oxides emitted by vehicles and factories.

The study, conducted by the United States Environmental Protection Agency (EPA), “provides a plausible explanation for the link between acute ozone exposure and death,” said lead author Robert Devlin of the EPA’s National Health and Environmental Effects Research Laboratory.

The study was published June 25 in American Heart Association’s journal Circulation.

Air pollution claims nearly 50,000 lives in the United States each year according to EPA estimates. However, further studies are needed to fully understand how these deaths occur.

Researchers recruited 23 volunteers, age 19 to 33 years and exposed them ozone gas for two hours which is equivalent to the EPA’s eight hour standard of 0.076 parts per million.

The volunteers were also exposed to clean air for two hours within the next two-weeks. The participants performed cardiac stress tests after both exposures.

None of the participants complained of any symptom during exposure to ozone. However, tests following ozone exposure showed that vascular changes occurred as a result of exposure to the gas.

Volunteers exhibited irregular heart rhythm, increased levels of signature marker for inflammation, and diminished ability to dissolve blood clots.

These changes lasted until the morning after ozone exposure, according to researchers. Changes were reversible among young and healthy individuals, they added.

Scientist suggest that ozone behaves like particulate matter which is also linked to death in older people with heart disease.

To reduce ozone exposure, researchers recommend closely monitoring air quality and minimizing outdoor activities when air quality outside is poor.