Three small children running in an open field with trees in the background.

Ah, summer. A time to run through sprinklers, soak up sunshine on a lazy afternoon, play sports outside from dawn to dusk, host backyard barbecues, and camp out under the stars.

Or is it? Summer is a time for fun, but as temperatures skyrocket and air becomes stagnant, ozone and air pollution rise to dangerous levels and prolonged exposure can cause respiratory problems for everyone.

What exactly is ozone?

There are two types of ozone layers in our atmosphere: a protective layer of ozone in the upper atmosphere (called the stratosphere) that screens out harmful ultraviolet rays from the sun; and harmful ozone in the lower atmosphere (called the troposphere), that poses significant health risks to people. It is the major component of the air pollution known as smog.

Harmful ozone is the chemical formed when emissions called hydrocarbons and nitrous oxides from motor vehicles, power plants or some industries interact with sunlight. Increased levels of ozone usually occur during the summer months when temperatures are high, days (and subsequently sunlight) last longer, and air movement is minimal. And while you can’t taste, touch or smell ozone, you can FEEL it as it irritates sensitive body tissue causing stinging eyes, shortness of breath, chest pain, wheezing and coughing.

According to the U.S. Environmental Protection Agency (EPA), ozone can irritate your respiratory system, reduce lung function, aggravate asthma and damage cells that line your lungs.

Who is most at risk from ozone exposure?

Several groups of people are particularly sensitive to ozone, especially when they are active outdoors – because physical activity causes people to breathe faster and more deeply.

  • Active children are the group at highest risk from ozone exposure because they often spend a large part of the summer playing outdoors. Children are also more likely to have asthma, which may be aggravated by ozone exposure.
  • Active adults of all ages who exercise or work vigorously outdoors have a higher level of exposure to ozone than people who are less active.
  • People with asthma or other respiratory diseases that make the lungs more vulnerable to the effects of ozone will generally experience health effects earlier and at lower ozone levels than less sensitive individuals.

Experts found that on high-pollution summer days, children with asthma were 40 percent more likely to suffer respiratory problems than on unpolluted days. There is also a notable increase in emergency room visits for elderly patients during smoggy days.

In general, as concentrations of ground-level ozone increase, more and more people experience health effects – the effects become more serious, and more people are admitted to the hospital for respiratory problems. When ozone levels are very high, everyone should be concerned about ozone exposure.

How do I know when ozone levels are dangerously high?

Most local television and radio news reports include air quality findings in their weather reports: Newspapers print air quality charts on a daily basis; and many air pollution control agencies publish air quality data on their websites.

EPA issues state and local air quality forecasts on a special consumer website,

What should I do when ozone levels are unhealthy?

The American Academy of Allergy, Asthma & Immunology (AAAAI) encourages everyone to take extra precautions during the hazy, hot and humid summer days that tend to foster high levels of harmful ozone.

When the air quality is deemed unhealthy, it is vital to remember that children with asthma are particularly vulnerable. On these days, stay inside as much as possible and limit strenuous outdoor activities to the early morning hours when ozone levels tend to be lower.

Daily AQI ColorLevels of ConcernValues of IndexDescription of Air Quality
GreenGood0 to 50Air quality is satisfactory, and air pollution poses little or no risk.
YellowModerate51 to 100Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution.
OrangeUnhealthy for Sensitive Groups101 to 150Members of sensitive groups may experience health effects. The general public is less likely to be affected.
RedUnhealthy151 to 200Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects.
PurpleVery Unhealthy201 to 300Health alert: The risk of health effects is increased for everyone.
MaroonHazardous301 and higherHealth warning of emergency conditions: everyone is more likely to be affected.

You certainly can’t stay inside all summer, but you can take steps to reduce exposure to the harmful effects of ozone pollution.

  • Air conditioning keeps indoor air cool and dry, while electrostatic, pleated or allergy-proof filters effectively minimize indoor circulation of pollens and mold. If you go out in your car, run the air conditioner and make sure it is set on “recirculate” to minimize the amount of outdoor air that comes in.
  • If you have allergies and/or asthma, work with your physician to ensure you have an up-to-date Asthma Action Plan in place. Know what triggers to avoid and what action to take if symptoms arise.
  • Finally, be creative! Pull out “rainy day” indoor activities such as board games or plan trips to the mall or movie theater as special “smoggy day” treats.

Ozone alerts and unhealthy air go hand-in-hand with summertime. By arming yourself with facts and taking the necessary precautions, you can escape the potentially devastating impact of ozone and focus instead on breathing easy.

Learn more about how weather can impact your allergy and asthma symptoms and check the allergy and asthma forecast for your area.