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Tribal-FERST Issue Profile: Ozone

Ozone is a gas composed of three atoms of oxygen. It occurs both in the Earth’s upper atmosphere and at ground level, and can be good or bad, depending on where it’s found.

Ground-level ozone is a harmful air pollutant created when emissions from cars, power plants, refineries and other sources chemically react in the presence of sunlight. Ground-level ozone is the main ingredient in smog and can be harmful to human health when breathed. People most at risk from breathing ozone are people with asthma, children, older adults and people who work outdoors or are otherwise active outdoors. Breathing ozone is associated with health problems such as chest pain, coughing, throat irritation, airway inflammation, reduced lung function and lung damage, and with aggravating conditions such as bronchitis, emphysema and asthma. Through the Clean Air Act, EPA develops air quality standards for ozone and other pollutants. EPA also establishes national and regional rules to help reduce emissions of the pollutants that form ozone.

Ozone that naturally occurs in the Earth’s upper atmosphere serves as the Earth’s “sunscreen,” forming a protective layer that shields us from the sun’s harmful ultraviolet rays. This beneficial ozone has been partially destroyed by manmade chemicals, causing what is sometimes called “a hole in the ozone.” However, through domestic and international action, this ozone layer is healing and should fully recover by about 2065. 

Visit the links below to learn more about ozone and what tools are available to reduce it.

General Information


Environmental Concentrations, Human Exposures, and Health Risks

Interested in learning more about a specific location? Type an address, city or ZIP code into the box on the right side of the map below. Click on the map to see a pop-up with information about ambient concentration, exposure concentration and cancer risk for the chosen location(s). Navigate to the next feature by clicking the small arrow(s) on the top right side of the pop-up.

Exposure and Risk Reduction Options

Strategies Implemented By Other Communities

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