Patient advocate: What is the AQI, and why should you care?

July 2025 made history as one of the Earth’s five hottest months on record. This July? More of the same.

The stubborn “heat dome” that blanketed a good chunk of the U.S. in June held on to make July 4th miserable for a lot of people. Dealing with the heat is tough enough, especially for children and those over 65, but with the heat come warnings about the AQI, or air quality index.

The AQI was implemented in 1968 by the then-National Air Pollution Control Administration, whose responsibilities are now under the Environmental Protection Agency (EPA). It tracks five major pollutants: ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide and nitrogen dioxide.

In short, it tell us how safe our air is to breathe. And it’s an important number to know in your locality. Fortunately, you can look up real-time AQI information for over 500 U.S. cities on airnow.gov, a partnership among the EPA, the National Oceanic and Atmospheric Association, the National Park Service, the Centers for Disease Control and Prevention, NASA and others.

You can also find worldwide data on AQI.in, an open-source AQI tracker developed by a New Delhi-based entrepreneur.

So it’s easy to find the information. The question becomes how you can use it to protect yourself and loved ones from pollution.

First, let’s break down the five pollutants and why they can be dangerous, especially to those with preexisting health conditions, such as asthma, COPD, bronchitis and heart disease.

• Ground-level ozone: The ozone layer up in the atmosphere protects us from most of the sun’s radiation. On Earth, though, it’s damaging to our lungs. As ozone concentrates and mixes with other pollutants, it becomes known as smog. It is currently one of the least well-controlled pollutants in the U.S. — and also one of the most dangerous, according to the American Lung Association.

• Particulate matter: Known as PM, this pollutant refers to microscopic solid or liquid particles suspended in the air, which can include dust, soot and smoke — a particular concern during wildfire season. These particles can penetrate deep into the lungs and even enter the bloodstream, leading to various health issues.

• Carbon monoxide: Known as CO, it is a colorless, odorless and tasteless toxic gas produced by incomplete combustion of carbon-based fuels such as gasoline and coal. It's extremely dangerous because it binds to hemoglobin more readily than oxygen, potentially bringing on oxygen deprivation, which can be fatal. It’s especially dangerous to those with heart conditions.

• Sulfur dioxide and nitrogen dioxide: These pollutants come primarily from the burning of fossil fuels, particularly in vehicles, power plants and industrial facilities. They pose serious health risks, including respiratory problems, and contribute to environmental issues like acid rain.

All of these are factored into the AQI, which can tell you when it’s safest to be outdoors, and when it’s not. The AQI is a numerical scale that is color coded. An AQI 50 or under is considered good (green); 51-100 (yellow) is moderate; 101-150 (orange) is unhealthy, especially for sensitive groups; and anything from 151 to 300 or more (red) is extremely hazardous to the general population.

Summer is typically when the AQI is more concerning. Air pollution is often made worse by intense heat and stagnant air, especially in populated areas. Drought conditions can bring on wildfires. If you recall, smoke from last summer’s wildfires in Canada had a huge impact on U.S. states.

Here are a few tips to keep yourself and your loved ones safer this summer from the pollutants measured by the AQI.

• Check the AQI before venturing out: It’s front and center on most weather apps.

• Go outdoors for yardwork or exercise in the morning: The AQI generally gets worse as the day heats up, and it’s also unfavorable in the evening due to accumulated pollutants and reduced wind speeds.

• Be prepared: If you or someone in the family has asthma, carry a rescue inhaler. N95 masks, which we learned to wear during the pandemic, can also help limit the amount of particulate matter you may inhale.

• Pay attention to indoor air quality: Use air purifiers with HEPA filters, for example. Dust and vacuum to control particulate matter. Frequently change filters in furnaces and air handlers. Control moisture to avoid mold.

The AQI is more than a number. It’s a guide to a healthier summer.

• Teri (Dreher) Frykenberg, R.N., a registered nurse and board-certified patient advocate, is the founder of NurseAdvocateEntrepreneur.com, which trains medical professionals to become successful private patient advocates. She is the author of “How to Be a Healthcare Advocate for Yourself & Your Loved Ones” and “Advocating Well: Strategies for Finding Strength and Understanding in Health Care,” available at Amazon.com. Contact her at Teri@NurseAdvocateEntrepreneur.com to set up a free phone consultation.