The Palisades and Eaton fires in Los Angeles destroyed more than 10,000 homes, businesses, and everything inside, from bathroom cleaners to electrical wiring.
Naturally, people in the Los Angeles area are reaching for their phones to see what the Air Quality Index (AQI) is saying about the air around them. But to most people's surprise, AQI was good to moderate across Los Angeles, even in the areas hardest hit by the fires. In Pasadena, the AQI fell from a high of 293 (a rating of “very unhealthy”) on January 11 to a low of 30 (a rating of “good”) the next day. How could that be?
Throughout the week, concerned residents participated in calls conducted by major organizations such as the Clean Air Coalition and local NPR station KCRW, asking questions such as: How far do they have to be from a fire to be safe from these pollutants? And how do they protect themselves from bad air?
Air pollution is a silent killer that no one is immune to. Every year, seven million people around the world die prematurely due to air pollution. In the United States, exposure to air pollution causes 100,000 to 200,000 deaths each year. Ed Abol, clinical professor of medicine at the Keck School of Medicine at the University of Southern California (USC), said long-term exposure can cause a variety of health effects in nearly every organ system in the body.
Wildfires play a natural and important role in ecosystems, especially in western states such as California. However, due to human-induced climate change, these fires are becoming more severe and frequent. This means more people are exposed to bad air.
But how bad is that atmosphere? Unfortunately, the answer is not as simple as you think. But here's what we know and don't know about air quality, and how we should think about lowering the risk of air pollution.
What AQI can (and can't) tell us about the atmosphere
The Environmental Protection Agency developed the AQI to give the public a tool to understand how good or bad the air is throughout the day. It uses data collected by 5,000 air quality monitors installed across the country to track levels of specific pollutants in the air and assign them numbers. The numbers correspond to color-coded categories to help people understand air quality and pollutants. Outdoor activities are safe.
The latest AQI can be found on EPA's AirNow website or AirNow app. We also provide fire and smoke maps that show where areas have AQI and smoke prospects.
Former Vox reporter Rebecca Lever explained:
AQI is calculated based on five standard pollutants regulated by the Clean Air Act: particulate matter known as PM2.5, ozone, carbon monoxide, sulfur dioxide, and nitrogen dioxide. When you look at your AQI on your phone or on a website, the numbers you see represent the main pollutants. Pollutants that increase AQI numbers tend to be PM2.5 and ozone.
In the case of the California wildfires, pollution sources are exposing millions of people in the greater Los Angeles area to smoke. And that smoke contains pollutants that are outside the AQI range. “It's true that when all these things are burning, there are more toxic compounds in the air,” said Rima, a professor of population and public health sciences at the Keck School of Medicine at the University of Southern California. Habre says.
When a fire burns down a home or building, certain volatile organic compounds, toxic metals, and toxic gases can be released into the atmosphere, all of which are not considered in AQI. As a result, people are becoming increasingly concerned about the air and the long-term health effects it will have, just as first responders did after the 9/11 attacks.
Wildfire ash, which can irritate the skin and lungs, falls from the air and settles to the ground, so it's not factored into the AQI, Habre said. Therefore, AQI can say that the air is good even if there is visible ash in the houses and streets.
There are ways to measure potentially harmful pollutants and chemicals in the air that are outside of the AQI range. That's how we know they exist in the first place, Avol says. “But we don't routinely measure all of these things everywhere and at all times, because that would be incalculably expensive,” he added.
Is AQI still useful in wildfire situations? Yes and no. While it remains a critical resource, it was not designed for situations like this unprecedented wildfire, which has destroyed thousands of buildings and structures. But even if AQI doesn't tell you the full picture, there are ways to help you make choices that consider safety and risk.
Think about the risks and how best to protect yourself
When I attended an air quality information webinar this week, I heard Los Angeles residents asking many of the same questions. “How far do I have to be from a wildfire to protect myself from bad air?” How can they keep their families safe?
The uncomfortable truth is that there is no one-size-fits-all answer to these questions. You may live several miles away from the fire, but if the wind is blowing in your home's direction, you may be at risk of exposure to bad air. But both Abol and Habre say people can analyze their own risks and decide how to lower the risk of exposure to bad air.
First, consider your own health and that of your family. Does anyone have a respiratory disease such as asthma? Does anyone have a weakened immune system? If so, these are further reasons to pay attention to the skies, Habre says.
You can then check your AQI and observe your environment. If the AQI indicates the air is good, but you smell smoke or there is a lot of ash, or if there is a fire and the wind is blowing in your direction. Please take precautions. Limit your time outdoors and wear appropriate N95s. A mask that helps remove PM2.5. Also, if you must go outside, check your shoes and clothes for ash when you enter the house. It is also a good idea to run an air purifier indoors with the windows and doors closed.
Understandably, it's a difficult and scary time for Los Angeles residents. Wildfires have destroyed entire homes and neighborhoods, and forced us to face the unpleasant reality that life is not without risk and there is no way to fully protect ourselves from the effects of such disasters. I'm strong in it. But that doesn't mean we're completely powerless to reduce the risk of short- and long-term health effects. “There are a lot of agencies here,” Habre said. Making informed choices, however imperfect, may be the best way to navigate these uncertain times.
