What you need to know about ozone

By Beth Gorman

“Why, Mom? It looks fine out there. Why can’t I go to practice today?”

How do you explain to 10-year-old Stephanie that there is something insidious in the air that she can’t see or even smell, but because she has asthma, she must avoid? It’s a question many families must answer during ground-level ozone season, which starts in April and continues all summer long in the Southwest.

When people hear the word “ozone,” they immediately think of the ozone layer, which is naturally formed miles above the surface of the planet. Ozone in that location is critical because it protects us from the sun’s dangerous ultraviolet light. You may remember concerns regarding a “hole” in the ozone layer. Reports indicate that actions taken worldwide decades ago to limit the production and release of certain chemicals that were damaging the ozone layer are working and the thinning is slowly healing.

Where does the “bad” ozone come from?

Ozone at “nose level” is formed when emissions from many different sources (natural and human-caused) combine photo-chemically with oxygen, under specific meteorological conditions. The ingredients for ozone include nitrogen oxides (NOx) and volatile organic compounds (VOCs) that are produced primarily when fossil fuels are burned (in engines of motor vehicles, power plants and gas-powered lawn equipment, for example) or when some chemicals evaporate (from factories, gasoline, solvents, paint, etc.) into the air. To add to the mix, some types of vegetation emit VOCs as well, including varieties of eucalyptus, bottlebrush, willow, oak and sycamore.

Ozone is a very complicated air pollutant since it isn’t emitted directly from a source and is created when just the right mix of pollutants are present under just the right weather conditions. The sun needs to be at a more direct angle above us, which starts in late spring and continues through the summer months and hot temperatures boost volatile chemical evaporation. In addition, calm air and a cloudless sky allow the intense solar radiation to trigger the reaction that creates ozone. And, ozone doesn’t stay where it is created. It can travel on prevailing winds and end up miles downwind of the original sources.

How is ozone harmful?

The worst thing about ground-level ozone is what it does to our lungs. When it meets tender tissue, like our airways and lungs, it oxidizes it, causing inflammation and irritation akin to an internal sunburn. This makes taking a deep breath more difficult and can actually be painful for people with respiratory disease, like asthma.

Which brings us back to Stephanie, and why it is best if she doesn’t play soccer when ozone levels are unhealthy. Health impacts are greater if you are outside breathing faster on a high-ozone day. Stephanie loves soccer and is a really good player, which involves a lot of running up and down the field. If she plays when ozone is elevated, Stephanie risks experiencing decreased lung function, wheezing, asthma attacks, increased susceptibility for respiratory infections and pulmonary inflammation, and the possibility of needing medical treatment or even a visit to the emergency room. Her mom understands this and is trying to protect her from these challenges. But it isn’t easy, especially when Stephanie looks out the window and sees clear skies and a seemingly normal-looking day.

Are our pets susceptible to ozone, too?

It isn’t just human lungs that are affected when ozone is high. Pets are not immune to the effects of ozone pollution, so on days when air quality is poor, they should be kept inside as much as possible and avoid strenuous outdoor activities. According to Dr. Wendy McClelland, DVM, in her article ‘Very High Risk’ Air Quality Affects Pets, Too, “Pets with short noses and flat faces, such as Boston terriers, Pugs, Bulldogs, Shih-Tzus, and cats such as Himalayan, Persian, Scottish Fold, are particularly at risk for respiratory issues during high-risk air quality alerts.” So, limiting exposure to outside air and reducing your furry friend’s level of excursion when he or she is outside will help protect their airways from irritation.

How can we protect ourselves?

To reduce exposure when ozone levels are elevated, you can do what Stephanie ended up doing and spend more time indoors, choose less intensive outdoor activities (like walking instead of running) so you don’t breathe in as much ozone, and you can plan outdoor activities during the morning or evening when ozone levels are lower. It is critical to check local air quality so you know if and when ozone is going to be high.

What can we do to reduce the emissions that form ozone?

There are so many different actions that we can choose from to improve air quality that everybody can do something to help keep the air ozone-free. And the majority of these activities will save us money, too, so there are benefits all around! Pick one or two from the list below to begin breathing cleaner air.

• Conserve energy and purchase Energy Star equipment when buying new items.
• Drive less—share rides, take transit, bike, walk whenever possible. You will be surprised at how stress is reduced when you cut the time you are driving alone in your car.
• Refuel your vehicle in the evening, be careful not to spill, don’t overfill your gas tank, and tighten your gas cap securely.
• Check tire pressure monthly and keep them properly inflated.
• Avoid planting high-VOC-emitting trees when adding to your landscape.
• Combine errands to skip trips.
• Replace gas-powered lawn and garden equipment with electric, battery, or manual when possible.
• Avoid engine idling. Park and go inside instead of idling in drive-thru lines. Check your phone before you leave the building, as opposed to while you are in your car.

Since the majority of the emissions that form ozone are vehicle-related, healthy air does start with us. The fewer the high ozone days, the more time our kids—Stephanie included—can be outside playing and being active, which is the healthiest place for them. Healthy air is in our hands!

Keep up with all of Green Living’s content by visiting our website.

Beth Gorman is a senior program manager for the Pima County Department of Environmental Quality in Tucson. She manages the Public Outreach and Education Section of the department, which consists of pollution prevention and public outreach programs regarding air quality and stormwater protection, as well as community outreach for air quality permitting, solid waste management, and water quality issues. She  also oversees the Arizona Department of Environmental Quality-funded Voluntary No-Drive Days/Clean Air Program and the Lawn & Garden Equipment Emission Reduction Program, and is the media spokesperson for the department.