Aug 29th, 2023

With spreading wildfires impacting the air we breathe in recent news, this is a perfect time to learn about Air Quality Index (AQI).

Do you know what is in the air we breathe? The vast majority of air consists of two components – 21% Oxygen and 78% Nitrogen. The remaining 1% is a mixture of other gasses. However, while contaminants may only form a small portion of the air around us, they can have an enormous impact on our health both long and short term. The most hazardous contaminants include carbon monoxide, ozone, and particular matter.

The U.S. AQUI is EPA's index for reporting air quality using a scale of 0 to 500. The higher the AQI value, the greater the level of air pollution and the greater the health concern.

Why A Problem

Besides being linked to early death in people with heart or lung disease, contaminants like particle pollution or ozone can cause a number or serious health problems that include:

  • Coughing
  • Wheezing
  • Breathing difficulties
  • Lung damage
  • Reduced lung function
  • Asthma attacks
  • Heart attacks
  • Strokes

Who It Impacts

Everyone, including healthy adults, can experience harmful effects from poor air quality. However, some people may be at greater risk. They are:

  • People with lung or heart disease (e.g. asthma; COPD)
  • Children and teenagers (their lungs are still developing)
  • Pregnant people
  • Older adults
  • Minority populations
  • People who are active outdoors, including outdoor workers

How To Protect Yourself

This is where AQI plays an important role. You may use AQI forecasts ( to plan outdoor activities or to check the current air quality.

Check AirNow

AirNow reports air quality using the official U.S. Air Quality Index (AQI), a color-coded index designed to communicate whether air quality is healthy or unhealthy for you. When you know the AQI in your area, you can take steps to protect your health.


The U.S. Environmental Protection Agency (EPA) establishes an AQI for five major air pollutants regulated by the Clean Air Act. Each of these pollutants has a national air quality standard set by EPA to protect public health:

  • Ground-level ozone*
  • Particle pollution (particulate matter, PM2.5, PM10)*
  • Carbon monoxide
  • Sulfur dioxide
  • Nitrogen dioxide

*Most state and local air quality forecasters issue forecasts for ozone and particle pollution, which are two of the most widespread pollutants in the U.S. A few areas also issue forecasts for nitrogen dioxide and carbon monoxide (Using Air Quality Index).

An AQI value of 100 generally corresponds to an ambient air concentration that equals the level of the short-term national ambient air quality standard for protection of public health.

↓ AQI values at or below 100 are generally thought of as satisfactory.
↑ AQI values above 100 indicate unhealthy air quality: at first for sensitive groups of people, then for everyone as AQI gets higher.

If the AQI forecast shows unhealthy levels, take these simple steps to reduce your exposure:

  • Choose a less intense activity
  • Shorten your outdoor activities
  • Reschedule activities
  • Exercise away from busy roads
  • Move your activity indoors
    • This may help with ozone because it's generally lower indoors. However, keep in mind that when particle levels are high outdoors, they can be high indoors too.
Best Practices

Can you help reduce some contaminants in the air? Absolutely! Here are a few tips:

  • Drive less. Bike or walk, carpool, or use public transportation.
  • Use energy efficiently. Choose ENERGY STAR certified products and turn off lights and devices that you are not using.
  • Choose clean heat. Upgrade to a heat pump, electric heat, or ductless heat pumps.
  • Keep tires inflated to the recommended pressure.
  • Don't let your engine idle. And, keep car, boat, and other engines tuned.
  • Refuel thoughtfully. Stop when the pump shuts off to avoid spilling and tighten your gas cap.
  • Use low-VOC paint and cleaning products. Seal and store them so they can’t evaporate.
  • Burn efficiently. If you use wood for heat, check EPA's Burn Wise for tips.
  • Don't burn leaves, garbage, plastic, or rubber.

By knowing this information about Air Quality Index (AQI), you'll be better equipped to take safety measures when needed and keep the air that you and your loved ones breathe as safe and healthy as it can be. Please help spread this awareness widely. 

Sources:, AQI Ozone Guide, AQI Particle Pollution Guide.