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Action Day

You may have heard of Knozone Action Days in Central Indiana, but you might be less familiar with what exactly ozone is or what you’re supposed to do when it hits peak levels. Here are the basics.

Ozone is a gas created when certain VOCs (volatile organic compounds) react chemically with NOx (nitrogen oxides) in the presence of intense sunlight. That’s why ozone levels spike in the summer months when it’s sunny and hot.

Ozone is most often associated with the ozone level in the stratosphere - where it shields the Earth below from harmful UV radiation. When it hovers over close to the ground as smog, however, ozone is harmful to human health and natural ecosystems.

PM2.5 - or particulate matter - is another unit of measure we talk about often. It refers to tiny solid particles or liquid droplets found in the air, including common pollutants such as soot, smoke, dust, and dirt, as well as chemical compounds like sulfates and nitrates. Your body is remarkably good at cleaning the air you inhale before it reaches your lungs and bloodstream. PM2.5 particles, though, are so small - you could fit 40 or more across the width of a single strand of hair - that they can sneak past the body’s defenses and damage health over time.

Knozone Action Days are declared when factors likely to produce high levels of ozone and PM2.5 align - high temperatures, sunny skies, little wind, etc. On these days, air quality can be unhealthy for Indianapolis and Central Indiana residents. Everyone should look to reduce their outdoor activity - especially strenuous exercise - on Action Days, but certain groups may be more affected than others. These include:

  • Children
  • The elderly
  • People with lung-related illnesses
  • Those who are especially active outdoors

Fortunately, there are many ways to help combat high levels of ozone and air pollution:

  • Refuel vehicles after 7pm. When you pump gasoline into your car tank or a gas can, some escapes as fumes. On hot summer days, these emissions can react with sunlight and heat to form ground level ozone. Refueling after 7pm prevents emissions from escaping during the hottest hours of the day when they’re most likely to form ozone.
  • Delay using powered lawn equipment - including mowers - until after 7pm. Someday, hopefully soon, we may see our energy grid powered completely by renewable energies like wind and solar. Until then, though, anything that runs on power - gas, electricity, etc. - runs on fossil fuels at some level and releases emissions when used.
  • Don’t let your vehicle idle. Letting your car idle for longer 10 seconds releases more emissions than simply restarting. Avoid heavy traffic times, drive-thru lanes, and any other idling on Action Days.
  • Choose a cleaner commute. Walk, ride a bike, take public transit or hitch a ride with a carpool to prevent or minimize emissions from driving.
  • Set the thermostat a couple degrees higher. Not only is it easier on your utility bill, saving the energy it takes to run your AC full blast reduces emissions and ozone.
  • Combine errands to reduce trips back and forth. You’ll save emissions and time. It’s a win-win.
  • Delay your use of garden, household, and workshop chemicals until air has returned to healthy levels. Some contain VOCs that may react with sunlight and heat to form ozone.
  • Tell others about Knozone Action Days and how they can help. Central Indiana is our home. It belongs to all of us, and preserving the quality of our air is our shared responsibility. Pass this information along to your friends and family, and tell them about ways they, too, can make a positive impact.

Of course, protecting air quality isn’t only important on Knozone Action Days. There are things you can do every day of the year to help clean up Central Indiana’s air. Check out our How You Can Help section for ways to get started.