top of page
Writer's pictureGroup Against Smog & Pollution

Welcome to Ozone Season, Allegheny Co.: Here’s What You Need to Know About the Air Pollutant

Updated: Mar 25



No, not the kind that’s way up high protecting us from those harmful UV rays. We’re talking ground-level ozone.

What the heck is ground-level ozone?


At the ground level, ozone is a harmful type of air pollution that is classified as a criteria pollutant by the U.S. Environmental Protection Agency (EPA) because its level in outdoor air needs to be limited based on health criteria. Heard of the term smog? Ozone is its main ingredient.


Since the temperature keeps creeping up into the 70s and 80s, it seems like a good time to remind folks that ozone is most prevalent during the warm-weather months we’re headed into now.


And yes, while ozone may be initially created in urban areas, it can travel long distances and accumulate in high concentrations far away from its original sources.


So, what causes it? Where does ozone come from?


Glad you asked. Ground-level ozone is created by chemical reactions that occur between nitrogen oxides (known as NOx) and volatile organic compounds (known as VOCs). This happens when sunlight chemically reacts with pollutants emitted by cars, power plants, industrial boilers, chemical plants, refineries, and even some species of trees.


And it can be harmful to your health: Inhaling ozone can cause everything from throat irritation and coughing to chest pain and airway inflammation that makes it difficult to breathe. Ozone can even reduce lung function and harm lung tissue, and exposure can exacerbate conditions like asthma and other breathing issues. Some scientists have compared ozone-caused lung damage to a sunburn.


People most at risk from breathing air containing ozone include people with asthma, children, older adults, and people who are active outdoors, especially outdoor workers. In addition, people with certain genetic characteristics, and people with reduced intake of certain nutrients, such as vitamins C and E, are at greater risk from ozone exposure. 


The EPA has developed a course called, Ozone and Your Patients’ Health, to educate medical professionals as well as patients and their families about the science behind ozone’s effect on respiration and how to manage their respiratory health using the Air Quality Index.


How can I reduce my risk when it comes to ground-level ozone? And my ozone footprint?


When it comes to minimizing your exposure to ozone, timing is essential: We’re most likely to see peak hourly values of the pollutant in the late afternoon – we’re talking from around 4 p.m. to 7 p.m. That means you can mitigate exposure by avoiding certain activities during that time of day.


How can you help reduce your ozone footprint? Here are a couple of recommendations from the Allegheny County Health Department (ACHD):


  1. Limit daytime driving. Combine trips when possible.

  2. Use public transit or rideshare.

  3. Walk or bicycle for short trips.

  4. Avoid prolonged idling and jackrabbit starts.

  5. Don’t refuel. If you must, do so after 7 p.m.

  6. Refuel carefully. Don’t top off your tank.

  7. Use latex instead of oil-based paint.

  8. Save energy. Wash dishes and clothes with full loads.

  9. Keep window shades/blinds closed during the day to cut down on air conditioning.


bottom of page