Ozone (O3)
Siarhei Tamasheuski avatar
Written by Siarhei Tamasheuski
Updated over a week ago

Ozone is a gas composed of three atoms of oxygen. It naturally occurs in the atmosphere and blocks out harmful UV rays from the sun. At ground level, however, ozone is toxic, harmful to breathe, and is often accompanied by other pollutants.

As sunlight is the major contributing factor, Ozone levels are usually higher in the summer and on warm afternoons. On a hot day, it will make the sky look heavy and a brownish-grey.

Where does it come from?

While other pollutants are emitted directly into the air, Ozone is made by a chemical reaction between the sun’s rays and nitrogen, from cars, industrial plants, and other sources, and volatile organic compounds (VOCs) in the atmosphere. And because these reactions happen up there, the effects are felt way downwind of their sources - across international borders and the oceans.

What are its effects?

Ozone attacks lung tissue by reacting chemically with it. Wheezing, coughing and shortness of breath can all be attributed to inhaling Ozone. Even healthy people can feel the long-term effects, including a reduction in lung function, inflammation of the lung lining, and respiratory discomfort.

When there are high levels of ozone, more people are admitted to hospitals with asthma-related health problems and COPD symptoms, and there is a greater risk of illnesses like pneumonia and bronchitis.

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