As fires continue to burn across Southern California, residents are rightfully concerned – and sometimes confused – about how the smoke affects air quality in their neighborhood and whether it’s safe to simply breathe.
“Until recently, we didn’t have to think about air as one of the things we had to worry about,” says Maryum Merchant, MD, a pulmonologist with UCLA Health. “People were more worried about food – what we’re eating, what we’re drinking. But of all your organs, the lungs are the only one constantly exposed to the air around you. So what you’re inhaling is going to eventually impact the health of your lungs.”
Wildfire smoke has led to unhealthy and hazardous air quality throughout the region, yet air quality changes constantly, depending on where you are and how the winds are blowing, Dr. Merchant says.
Here’s what you need to know to keep your lungs healthy during and after the fires:
Where can we find out about the air quality in our neighborhood, and how can we make sense of the numbers?
AirNow.gov, managed by the Environmental Protection Agency, provides a composite air quality index (AQI) based on multiple pollutants, including ozone and particulate matter. PurpleAir offers real-time, hyperlocal air quality data based on sensors throughout the community, but primarily measures particulate matter and may not account for ozone levels, Dr. Merchant says.
It’s important to remember that each platform uses different algorithms to estimate air quality, so readings may vary slightly, she adds. Checking multiple sources can provide a more comprehensive understanding of current air conditions in your area.
The AQI captured by AirNow is a composite of several pollutants, including ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide and nitrogen dioxide. It measures AQI on a scale from zero to 500. Zero to 50 is considered good; 51 to 100 is moderate; 101 to 150 is unhealthy for sensitive people, such as those with asthma; 151 to 200 is unhealthy; 201 to 300 is very unhealthy; and more than 300 is hazardous.
Of particular concern after wildfires is a marker called PM2.5, which refers to particulate matter, the tiniest particles in the air, Dr. Merchant says.
“They can not only be inhaled, but inhaled deeper into the airways, and sometimes they can be absorbed into blood circulation as well,” she says. “So they have a wider range of health implications than some of the larger particles.”
N95 masks can help protect against inhaling these particles.
Is it safe now to exercise outdoors without a mask?
It depends on what the air quality is in your neighborhood at that time, Dr. Merchant says. Just because the air looks clean doesn’t mean the air quality is good, she adds: Check the numbers.
“If the air quality is good, you can exercise outside without a mask,” she says. “But if you’re going to spend a lot of time outdoors when the air quality is poor, then it’s recommended that you wear a mask.
“And if you are going to enter an area recently affected by wildfire, and there’s a lot of stuff in the air – including PM2.5 particles – that’s when you want to use an N95 mask.”
Is using an air purifier with a HEPA filter the best way to keep indoor air safe? Is one needed for each room?
“Air purifiers with HEPA filters are very effective in that they can remove 99.9% of the particles,” Dr. Merchant says. “When we’re talking about wildfire smoke, some of these particles can be very, very tiny, and a good HEPA filter can remove these particles.”
In areas affected by wildfires, it’s a good idea to keep the air purifier running constantly, she says.
Air purifiers also remove mold, dust and allergens, she adds, so they’re helpful for people with asthma, allergies, chronic obstructive pulmonary disease (COPD) or other chronic lung conditions.
Enclosed spaces, such as bedrooms, need their own air purifiers. A single unit can be used in open spaces, such as a kitchen-dining room, Dr. Merchant says.
Should we shower and change clothes after being outdoors in poor-quality air to avoid bringing particles into the house?
It’s a good idea, Dr. Merchant says.
“If you have been outside during times of high pollution – wildfire smoke, dust storm – depending how long you’ve stayed outdoors, these particles can settle onto your skin, your clothes, your hair, and you will be bringing them inside,” she says.
In those cases, it’s wise to shower and change clothes and put dirty clothes directly into the washing machine or clothes hamper, “just like we did during COVID times,” she says.
Do dogs need a bath, too, after a walk outside?
If you’ve been out with your dog when the air quality is unhealthy or hazardous, it’s a good idea to wipe down the pooch’s paws and legs with a wet towel, Dr. Merchant says. Otherwise, they can spread particles onto carpets and couches.
Even if the air quality is good, she recommends brushing your dog and wiping its paws and belly after a hike to avoid bringing pollen and dust inside.
If you are returning to a fire-damaged area and your pet is walking in ashes, be sure to give its paws, legs and belly a thorough wipe-down, she says.
Is it safe for people with asthma or chronic lung conditions to continue living in Los Angeles as we rebuild?
Air quality can change from hour to hour and day to day, Dr. Merchant says. When the air quality is bad, she advises staying indoors with the windows and chimney flues closed and air purifiers on. Avoid outdoor exercise. If you must be outside, wear a N95 mask. When driving through areas affected by wildfires, keep the car windows rolled up, even when there’s not an active fire.
“You have to be much more careful if you have an underlying lung condition,” she says.
As for how long it will take for air quality to improve in areas affected by wildfire, scientists aren’t sure, she says.
“It’s hard to say, because when we have destruction on such a massive scale, when so many houses are affected and we have all these toxic particles in the air, it’s hard to know how quickly that air will be cleaned up,” Dr. Merchant says. “It might even take a year. Some experts say it might take two years.”
Meanwhile, she suggests checking the air quality in your area regularly and taking precautions to protect your health.
