MARY LOUISE KELLY, HOST:
Air quality in Los Angeles has improved since last week, when the wildfires first started - some good news there. There are still questions, though, about how safe the air actually is now. So we turn to NPR's Alejandra Borunda with the climate desk for some answers. Hey, there.
ALEJANDRA BORUNDA, BYLINE: Hey.
KELLY: Hi.
BORUNDA: How's it going?
KELLY: OK. So there is data, obviously, that people can turn to - try to figure out if the air is safe to breathe. I'm thinking of things like the Air Quality Index. Does that give you enough info to make a call?
BORUNDA: Yeah. It's a great question. And the short answer is no, but it's a good starting place. So the AQI incorporates measurements of five different air pollutants regulated by the Environmental Protection Agency, like fine particles and ozone. But the AQI is really designed to tell you about normal kinds of pollution, like car exhaust or smog, and scientists think that smoke carries different and potentially higher risks. So what several experts told me is AQI is a helpful gauge to indicate when wildfire smoke or ash is in the air, but it's not going to tell you everything.
KELLY: Aha. So what does it miss?
BORUNDA: Yeah, it misses - it does not take into account many gas or particle contaminants that are produced during wildfires, especially ones that burn through structures, like we saw here. Think of all the synthetic roofing tiles, the couches, the appliances - all that stuff that burned. Those can produce carcinogens, like benzene or formaldehyde or asbestos fibers or metals. Michael Jerrett is a wildfire smoke expert at UCLA. He puts it this way.
MICHAEL JERRETT: Those are definitely a health concern, and there's no way to really prevent it.
BORUNDA: Once those catch on fire, the contaminants get up into the air, and then they spread through smoke and ash. And the other factor here is wind. If the winds shift, air quality can change really quickly.
KELLY: So are you telling me, OK, yes, good news - the air has improved in LA. It may even look better, like brighter skies, but those carcinogens - things like benzene - they could still be in the air?
BORUNDA: Yeah. This is what's tough - is, honestly, we don't know. It's not really measured consistently. The fire isn't burning houses and cars anymore, so that's really good. But the old ash that's spread all over the city - that can still get picked up and spread around again by any new wind. So what experts told me was, keep close track of the AQI 'cause that will at least tell you if there's stuff in the air. And if there is, it's probably safe to assume that there's some nasty stuff, too, but it's not like last week.
And several experts suggested looking at purple air maps for really neighborhood-scale information. Or you could even go more small-scale, like wildfire smoke expert Luke Montrose from Colorado State University. He always has personal air quality monitors on hand, like these little ones that clip onto a backpack.
LUKE MONTROSE: Knowledge is power. I have a whole bag of them that I carry with me.
BORUNDA: Again, these won't tell you about the toxic contaminants, but they can give you a rough sense of the risk.
KELLY: Bottom line, then - what is the menu of things that people should be thinking about doing to protect themselves, protect their families?
BORUNDA: Yeah, I think the good news is that it's - honestly, it's pretty straightforward. Keep track of AQI as an indicator, again. Run the air filters you have in your house and wear masks to help with particulates. Those can help with things like asbestos, for example. Activated carbon filters can help with the gases, like benzene. But overall, I think this is the message. There's a saying - the dose makes the poison. So if you're worried, err on the side of caution. Lisa Patel is a pediatrics expert at Stanford, and she says that could mean limiting time outside right now. And...
LISA PATEL: Trust your nose. And so if you're smelling that pollution, go ahead and put that mask on.
BORUNDA: As for schools, Patel says lots actually updated their HVAC systems during the COVID-19 pandemic, but you could always get some portable air filters for your kids' classrooms.
KELLY: All righty (ph). Thank you, Alejandra.
BORUNDA: Thanks so much.
KELLY: That's NPR's Alejandra Borunda. Transcript provided by NPR, Copyright NPR.
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