The GreenDallas Guide to Ozone and Ozone Alerts

The GreenDallas Guide to Ozone and Ozone Alerts

Ozone season begins in March and lasts through November. An ozone alert is issued every time the ozone level increases on the ground. So, what is ozone? It’s a gas that occurs in the upper atmosphere and at times on ground level. It’s good to have in the upper atmosphere because it protects the Earth from the sun’s harmful ultraviolet rays. It’s bad at ground level because it’s the main ingredient of urban smog and can be harmful to breathe.

Here’s why paying attention to the ozone level matters:

  1. What happens when you breathe it? Breathing ozone can cause an array of issues including chest pain, coughing, throat irritation and congestion. It can worsen bronchitis, emphysema and asthma.
  2. Who’s vulnerable? Ozone is a general human health threat, but those most vulnerable are children, the elderly, people with respiratory issues and people who work outside.
  3. How can you prevent it? The best thing you can do on an Ozone Alert Day is to use public transportation to lower emissions, combine errands and reduce trips, and reduce outdoor activity that could exhaust you.

Below is a graphic of the color-coded ozone alert system that explains the Air Quality Index featuring Arlo the airmadillo.

Ozone Air Quality Index Graphic  

For more information about Ozone, following the Department of Environmental Quality’s social media pages on Facebook and Twitter.  To sign up for air pollution alerts, visit

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