Ozone Action Days and What You Can Do to Help

We’re all familiar with the term “ozone action day,” “ozone warning day,” or “ozone watch day” and typically associate these designations with a hot summer day.  But what do they really mean?  Below we explain the significance of ozone pollution and what you can do to make a difference.

Ozone is a form of oxygen not emitted directly into the air, but formed through chemical reactions between natural and man-made emissions of volatile organic compounds (VOCs) and oxides of nitrogen (NOx) in the presence of sunlight.  Sources of these pollutants include automobiles; gas- and diesel-powered motors; refineries; chemical manufacturing plants; solvents used in dry cleaners and paint shops; and wherever natural gas, gasoline, diesel, kerosene, and oil are combusted.

When found in the upper atmosphere (i.e., the “ozone layer”), ozone is a good thing and helps keep out the sun’s harmful rays. However, when ozone forms near the ground, it is a pollutant that can affect human and environmental health.

Ground-level ozone pollution, or “smog,” is the periodic increase in the concentration of ozone in the air. It is mainly a daytime problem during summer months because warm temperatures play a role in its formation. When temperatures are high, sunshine is strong, and winds are weak, ozone can accumulate to unhealthful levels.

The biggest concern with high ozone concentrations at ground level is the damage it causes to human health, vegetation, and common materials (e.g., rubber, surface coatings). High concentrations of ozone can cause shortness of breath, coughing, wheezing, headaches, nausea, eye and throat irritation, and lung damage. People who suffer from lung diseases like bronchitis, pneumonia, emphysema, asthma, and colds have even more trouble breathing when the air is polluted. These effects can be worse in anyone who spends significant periods of time exercising or working outdoors.

The U.S. Environmental Protection Agency has developed an Air Quality Index that specifies when local air quality is healthy and unhealthy.  When ozone levels are predicted to reach unhealthy levels or are currently being measured at unhealthy levels, an alert—sometimes called an “ozone watch” or “ozone warning”—is issued. These notices caution citizens to limit their time outdoors as well as remind them to take actions to help reduce their emissions that contribute to ground-level ozone. To learn more about air quality in your region and sign up for alerts, visit http://www.enviroflash.info/. You can receive alerts via e-mail, Twitter or download a smart phone app.

Simple actions everyone can take to reduce air pollution include:

At Home

  • conserve energy by setting your air conditioner at a higher temperature and turning off unused lights
  • use energy more efficiently by looking for ENERGY STAR® certified appliances and lighting
  • switch electricity use to non-peak periods by running your dishwasher and clothes washer in the evening
  • wait to mow the lawn until after 6:00 pm

On the Road

  • limit driving by combining trips, carpooling, and taking public transit
  • avoid idling by skipping the drive-thru line and minimize driving when roads are most congested
  • postpone refueling your vehicle until after 6:00 p.m. and don’t top off the tank
  • keep your vehicle well maintained by getting regular oil changes and keeping tires properly inflated

For more tips on how you can help, visit the Air Now site.