OKLAHOMA CITY (AP) -- An Ozone Alert has been issued for Friday in central Oklahoma and the Tulsa metropolitan area.

The Association of Central Oklahoma Governments issued an Ozone Alert for central Oklahoma, while the Department of Environmental Quality issued one for the Tulsa metro area.

Ground-level ozone is the primary component of smog and is a health and environmental concern from May to September.

It's formed by nitrogen oxides and volatile organic compounds mixing in the presence of intense sunlight. Little or no wind further adds to the problem.

People with increased health risks include those with asthma, adults over 65, children under 18, persons with chronic obstructive pulmonary disease, people with cardiovascular disease, and those with diabetes.

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