Episode 3: What Is AQI?

The AQI, or Air Quality Index, is a simple way to communicate how clean or polluted the air is, using numbers and colors that anyone can understand. But what does it all mean, and how does that affect you?

In this episode, we decode the AQI and help you make sense of what that means for you and your family.

Transcript

Hey everyone and welcome back! This is Inhale, Exhale, an air quality podcast about the air we breathe. My name is Ms. Carmen, I’m a science educator in Brooklyn, NY, and I am your host. At the time of recording this podcast, the outside temperature is 59 degrees and the AQI is 12. 


Imagine this: You wake up in the morning, check your  weather app, and see a number next to something called the AQI— the Air Quality Index. It’s 85. Sounds fine to you, there’s no local alerts, so out you go for a run, but halfway through, you feel… off. Your chest feels tight, and your throat starts to dry and scratchy. By that afternoon, you have a slight headache and your throat burns. What’s going on?

That number—AQI 85—was telling you something. The air quality wasn’t great.

Today, we’re talking about the Air Quality Index—what it means, how it works, and why you should check it just how you check the weather.


Let’s start with the basics. AQI stands for Air Quality Index. It’s a simple way to communicate how clean or polluted the air is, using numbers and colors that anyone can understand. The AQI scale runs from 0 to 500, with different colors representing different levels of health risk:

Green (0-50) → Good. You can breathe easy with no concerns!


Yellow (51-100) → Moderate. For most people this AQI is fine, but after more than a day of this, you’ll likely get the dry, scratchy throat feeling even if you have absolutely no preexisting conditions.

Orange (101-150) → This is unhealthy for sensitive groups, and if you have asthma, you’ll feel it. Some localities may issue an air quality advisory once the AQI reaches this level, since 24 hours of exposure at this level affects everyone..

Red (151-200) → This is unhealthy for everything that breathes, and localities will issue an air quality alert or even declare an air quality emergency when the AQI reaches this number. 

Purple (201-300) → Very unhealthy. At this level, folks are urged to remain indoors.

Maroon (301-500) → Hazardous, and serious health risks will be experienced by anyone breathing in this air.

Unfortunately, on June 8th 2023, NYC experienced hazardous air quality conditions. Smoke from northern Canadian wildfires made it all the way down here on a low pressure system and our local AQI was measured at 340 at 4pm.


Where do these numbers come from? Well, they’re based on measurements of the presence of five major air pollutants:

Ground-level ozone
Particulate matter (PM2.5 and PM10)
Carbon monoxide
Sulfur dioxide
Nitrogen dioxide


So why do we have an air quality index? The short answer: People were getting sick and dying. Unfortunately that’s usually how serious things need to get to impact change.

Let’s take a quick trip back to London, 1952. At that time the city was covered in a dense, toxic smog caused by coal burning. Over just a few days, more than 10,000 people died from respiratory illnesses. Los Angeles in the 1940’s was best represented by thick smog from cars and industry, which made it hard to breathe. People were showing up at hospitals with burning eyes and inflamed lungs on a regular basis.

Events like these created a need for a simple, standardized way to understand how the air was doing. That’s why countries started developing air quality indexes. In 1976, the U.S. Environmental Protection Agency (EPA) launched the AQI system, and today, variations of it are used worldwide, though the basis remain the same for unified understanding.

Checking the AQI can help you make smart choices about your daily outdoor activities. Planning a run? Depending on the AQI, you might want to consider exercising indoors. Have asthma or other respiratory issues? Check the AQI before opening your windows and introducing outdoor air inside your home.
Traveling? Air pollution levels vary greatly by city and season. Some of the most polluted cities in the world regularly hit AQI levels above 200. You’ll want to check before you go.

You can check AQI levels a few ways online, all for free:
A lot of weather apps now include AQI data on a 12 to 24 hour average, PurpleAir.com has real-time, live local air sensor data , and you can also check AirNow.gov if in the US


Let’s clear up some common myths about AQI.

Myth: If I can’t see pollution, the air is fine.
Fact: Some of the most harmful pollutants, like PM2.5, are microscopic. You can’t see them, but they still get deep into your lungs, causing short and long-term consequences.

Myth: A little air pollution won’t hurt me.
Fact: Even short-term exposure can cause inflammation, headaches, and fatigue. Long-term exposure to air pollution? That’s already been linked to asthma, heart disease, and cognitive decline.

Myth: AQI is only important in big cities.
Fact: Rural areas can, and do have poor air quality, some worse than cities do. Wildfires, agriculture, and high pollen seasons all contribute to the AQI.


So, what’s the big takeaway? The AQI is like a weather report for the air and your lungs. Checking it helps you protect your health, plan your day, and understand what’s in the air around you.

Next episode, we’re bringing the focus inside—because believe it or not, the air inside your home might be more polluted than the air outside.



Thanks for tuning in and very special thanks to support from friends who made this podcast possible. Thank you! Until next time—breathe easy and don’t forget! No matter where you are, like it or not, we’re all in this together. This is Ms. Carmen signing off from Inhale, Exhale, an air quality podcast.