Experts on Camera

Dr. Stephanie Holm: Wildfire smoke and children’s health

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Smoke from wildfires is harmful to human health, and this is particularly true for children.

On August 24, 2021, SciLine interviewed: Dr. Stephanie Holm, a pediatrician and co-director of the Western States Pediatric Environmental Health Specialty Unit at the University of California, San Francisco. See the footage and transcript from the interview below, or select ‘Contents’ on the left to skip to specific questions.

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STEPHANIE HOLM:  I’m Stephanie Holm. I am a assistant clinical professor at the University of California, San Francisco, and I’m the co-director of the Western States Pediatric Environmental Health Specialty Unit.

Interview with SciLine

What kind of health risks result from wildfire smoke?


STEPHANIE HOLM: Sure. So the most well-studied health risk of wildfire smoke in kids is respiratory. So that includes things like upper respiratory symptoms, like runny nose, itchy eyes, scratchy throat, but also lower respiratory things like pneumonias, worsening asthma symptoms. We also know, though, that some of the pollutants in wildfire smoke can also cause wide-ranging other health effects. So that includes things like effects on obesity, problems with learning and also increasing the risk of lung cancer later in life.

Why are children more vulnerable than adults to the effects of wildfire smoke?


STEPHANIE HOLM: So children are more vulnerable than adults to the effects of wildfire smoke for three reasons. The first is that they breathe more air and, therefore, breathe more pollution relative to their size than adults do. So they effectively get a higher dose. The second is that kids spend more time outside and more time exercising. And that’s a good thing, right? We want kids running around and playing and being outdoors, but it means that they’ll get more exposure to wildfire smoke than someone like me that spends a lot of my day at a desk. And then the third is that children are still growing and developing, and so toxic exposures in childhood can disrupt patterns of growth and development and end add up having lifelong effects.

What do we know about the risks of drifting smoke, far away from the wildfires themselves?


STEPHANIE HOLM: So the health effects of wildfire smoke can happen really anywhere that smoke can drift. And so many children can be affected by wildfire smoke that happens from one single wildfire event. I think we know a lot about what is contained in wildfire smoke, and it’s what we would call a really heterogeneous mixture. There’s a lot of different things in wildfire smoke. What we don’t know, what we’re still learning, is exactly how that smoke changes over distance. As it travels really far, how exactly does the composition of that smoke change, and how does it interact with other factors, like weather? But what we do know is that the small particles, which have a lot of known health effects, those do travel very far. And so we expect that the health – most of the health effects of wildfire smoke are going to be the same, really, wherever that smoke travels to.

What should parents do to protect their families from smoke and other harmful wildfire-related environmental exposures?


STEPHANIE HOLM: Even though we know that wildfire smoke has health effects for kids, the encouraging thing is that there are things we know that you could do to mitigate those effects. So the first is to know how to check your air quality. I recommend using or if you like looking at a map. Those are run by the EPA, and those are more accurate than sites run by other third-party companies. Any time the air quality index is in the orange range or above, that’s considered unhealthy for sensitive groups, including children, and so you’d want to be taking steps to reduce your child’s exposure. The second is to make your indoor air as clean as you possibly can. So if you have an HVAC system, like central air, you can replace the filter in your HVAC system with a filter rated with a MERV, that’s M-E-R-V – MERV 13 rating or higher. That will filter out most of the particles from wildfire smoke. If you don’t have central air, you can use a portable air cleaner. You want to make sure that you’re using the ones that are filter-based, not electronic because the electronic ones can produce ozone, which has bad health effects, and ions, which we’re starting to realize have some health effects as well. So you really want to stick with the HEPA filter-style air cleaners. And you want to make sure that you get one that has a large enough clean air delivery rate that it can move the volume of air in your space two or three times per hour so that you know you’re getting it clean. So that’s the second thing. And the third is to have NIOSH-certified N95 masks available for you or your kids to wear if you have to be outdoors. The safest place to be is in an indoor space with clean indoor air, but you may have to go outdoors for short periods of time. And so you can use a nine – N95 respirator mask. You want to make sure it’s one of the NIOSH-certified kind to protect yourself from wildfire smoke exposure when you have to be outdoors.

How do we balance protection from wildfire smoke with protection from COVID?


STEPHANIE HOLM: Balancing how to protect kids from wildfire smoke and COVID-19 at the same time is something that folks are really worried about right now. I think the key thing is to focus on interventions that will help with both. So for indoor air, that’s filtration. People often get really worried because they know that for COVID they want to bring in lots of outdoor air, but they worry about doing that during wildfire smoke times. If you have good filtration – so, for example, you have an HVAC system with a MERV 13 filter on it or higher – you’ll be filtering that air, and so that’ll give you benefits both for COVID and for wildfire smoke. So really focusing on the filtration, making sure you’re filtering your air well in addition to ventilating it as you want to for COVID will help with both those things. From a masking perspective, it’s important to realize that though cloth masks are helpful for COVID, they cannot be relied upon to protect from wildfire smoke. Disposable, medical or surgical-type masks will provide a small amount of protection from wildfire smoke in addition to helping protect from COVID. And NIOSH-certified N95 masks will provide much more protection from wildfire smoke in addition to protecting from COVID. So you really want to focus on those interventions that will help with both the COVID exposure and the wildfire smoke exposure.

Where can people find resources to stay informed and updated?


STEPHANIE HOLM: So we at the Western States PEHSU have a lot of resources for wildfire smoke. We’re constantly updating it. We have things for the public, for families, as well as for health care providers. So feel free to check that out. That’s at W-S PEHSU – Or we’re also on Twitter at @wspehsu.

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