For the past four years, autumn in California has become synonymous with wildfire season. Each year has brought new fires, traumas and complications to the state with far-reaching consequences. This has culminated with 2020 setting a new standard of destruction to the tune of some four million acres burned (roughly the land mass of Connecticut).
Beyond the immediate destruction of the wildfires themselves, the smoke they generate has become a statewide health hazard, and the Peninsula itself has been particularly hard hit with long stretches of toxic air over the past few months. In this regard, Northern California's wildfire smoke has become an ever-pressing area of study in recent years to determine the true impact on the heart, lungs and immune system.
So for a more accurate sense of the health risks that come with our smoky skies and how to better navigate them moving forward, we spoke with Mary Prunicki, Director of Air Pollution and Health Research for the Sean N. Parker Center for Allergy Research at Stanford University.
As a veteran researcher in the effects of air pollution, Dr. Prunicki answered our questions about day-to-day health amid fire season, whether or not masks actually help and why the smoke can make you more susceptible to viral illnesses.
Take a look…
This interview has been edited for length and clarity.
What would you tell someone on the East Coast about the wildfires here and their national implications?
Wildfires are not just a regional problem. For one, with climate change, they're going to be occurring in more locations, be larger and impact more people.
And there's a study in Finland, where they had vegetative fires, and the smoke from those vegetative fires actually impacted several countries in Europe. They estimated that it caused over 600 pre-mature deaths.
There's the fact that the smoke can travel and if it does, it typically stays high in the air in a cloud. If something meteorological causes it to go downward and invade the air people are breathing, not only will they be susceptible to the same types of health effects, but as the smoke ages, there's thought that it becomes more toxic. They may be exposed to an even more toxic smoke than where the fire originated.
In your years of studying air pollution, how unprecedented is what we've experienced with these escalating wildfire seasons?
This past month has been totally unprecedented. In the Bay Area we had 30 straight days of spare the air days, which has never happened, and then I think we went into another 12 days straight of spare the air days, something similar to that. That's never happened in this area.
The total amount of acreage that has been burned and the fact that in California, Oregon, Washington, it was some of the worst air quality in the world at times, to my knowledge it's never happened like that before.
Is it possible to overstate the lethal implications of your findings about smoke inhalation?
I don't think so. There's been studies, actually one came out this year, that showed that out of hospital cardiac arrests — which is when for a cardiac arrest, your heart just stops, it's not a heart attack, it literally just stops, people collapse and die on the spot — when there's wildfire smoke exposure, there's increased incidents of cardiac arrest. They looked at the ages: it was ages 35 and above, which was pretty shocking to me it wasn't just the elderly population — typically . . . 65 and up.
For respiratory, we know that it doesn't take much of an increase in PM 2.5 (particulate matter, fine inhalable particles 2.5 micrometers or smaller, which is about 30 times smaller than a human hair) and you'll get increases in ER (visits) and hospitalizations for asthma, COPD (chronic obstructive pulmonary disease), respiratory infections, medication use — that's been consistent no matter where the studies have been done.
A conversation that sprung up around COVID was preparedness. What should we know related to that and wildfires?
More of the mitigation needs to occur at the individual level at home to be prepared to stay indoors and do the things they need to do to filter the air. That would be my sense. The goal would be to prevent the exposure.
Hopefully our country can get situated with N95 masks — that's something that should be on hand for everybody, if needed. Everyone says the best advice is to stay indoors because there are problems with the N95 masks. A big one is the masks don't filter gases. Wildfire smoke contains…all these other things, that even if you have a mask on, you're still being exposed to non-particulate toxins. I definitely think we need the masks, but the emphasis should still be on: staying in the home and filtering the air.
From the unhoused to the elderly to autoimmune compromised, how much of a cultural shift do we need to consider to mobilize to protect these populations during fire season? There's people who don't have a home to stay in and shut their windows.
I'm not sure at the state level what the solution would be, whether it's mobile units that can be moved around if there's a wildfire for people to come in and get good air. I know there's a huge problem with the elderly also because if you do close up the house, and you don't have air conditioning, now you have to worry about an elderly person having heat stroke or something like that.
I think a lot of things, hopefully, can be done before the next wildfire season so we're not in this type of predicament again. The smoke itself makes you more vulnerable to viral pathogens. This year it's COVID, but who knows (going forward)? I don't think it's a one-time thing.
There's also studies showing a community that was exposed to wildfire smoke, the influenza rate that fall was worse. So it remains to be seen what's going to happen in the next month or two, hopefully it won't be as bad as some people predict.
Your research has started to gain insight from retired firefighters. What do you get from them sharing their experiences in addition to their blood work?
A lot of these fire fighters have respiratory issues obviously, but also there's an increase in the number of deaths associated with cancer for fire fighters. One estimate was 16 percent of firefighter deaths are cancer related, which is huge. There's increases in things like testicular cancer, 102 percent increase; Non-Hodgkin's lymphoma and most myelomas, like a 50 percent increase; brain cancer, at like a 30 percent increase. Those are big increases.
We know that by the time they retire, their health is typically very compromised. Part of what we're trying to do is look at cardiac function and immune function in these guys that have been chronically exposed for years to figure out exactly what the smoke does to your body.
There's another essential worker population that has suffered during the smoke, which are farmworkers. I'm wondering if there's going to be research and studies in that population.
It's true the farmworkers (especially in the Central Valley) are exposed to poor air quality, and they get a lot of wildfires … The Central Valley is typically where we do our research and I think it could be a great study if we can look at the usage of wearing masks and other measures in that population.
It hasn't been done by us. I believe there was maybe a cohort out of Berkeley that was looking, not specific to wildfires, I think just in terms of air pollution in that type of group. It would be a good population to study, it's just difficult to do remotely.
Does the resistance to masks in current public health discourse related to COVID-19 concern you about resistance to masks that can protect people from wildfire smoke?
Wearing a mask for COVID has a different purpose than for wildfire. We did do a small study that's not published yet. We looked at mask usage in a group we recruited on campus — honestly, most participants were undergraduates or they worked at Stanford, somehow most were affiliated in some way, we had 60 or 70 participants, the majority were wearing masks during this past wildfire but at least 10 participants had access to N95 masks but chose to wear like a cloth mask. I wonder if people are getting confused or mixed messages on what a mask will do for you in what situation.
There's been increasing awareness around Native fire management in the form of controlled burns. Do you believe exploring that and other options is necessary to reduce the scale of wildfires and resulting smoke we're experiencing?
Yeah. We did do a study, we had sampled blood from children in Fresno for an air quality study, but we realized there was a good chunk of them had been exposed to wildfire or prescribed burn. We did analyze their blood and publish a paper on that. We found that exposure to wildfire smoke is more detrimental to your health than a prescribed burn, which, intuition would say that's true, but it was good to see that we can actually see at the immune level.
I would hope that studies like that and others would encourage people to not fight controlled burns.
For example, a lot of the controlled burns were halted because they didn't want to put smoke in the air with COVID going on. I haven't seen numbers on how many were performed versus how many they originally intended to do, but I know it was reduced. I would not be surprised if that played somewhat — not totally — into what we saw this fall. I think there's a bigger role for prescribed burning than what's been done in recent years.
For people caught up in the day-to-day, it's easy to forget this wildfire issue is recurring and volatile. What are the main takeaways for how to approach, prepare for and understand the situation?
I think people were somewhat more prepared this year after we experienced the Camp Fire (2018). I do think there needs to be some formal community planning. From the level of communicating what is going on, who needs to be evacuated, down to how can you fireproof your home, how can you in your own yard take care of hardening, and should we be looking at regulations not allowing new developers to go in to the urban-wildland interface so much, for the areas that they predict there's going to be fires. What can be done ahead of time? Probably more than that has happened in the past.
Preparation is key. Just because air doesn't smell bad doesn't mean you shouldn't be out in it. It's really important to check the AQI (air quality index) and at a minimum follow that. Even if the AQI is fine, listen to your body. There is a lot of science behind the fact that probably, it makes you more susceptible to viral illnesses, not just COVID. On many levels, the more you can stay away from the smoke, a person will be better off health-wise.
This article was originally published Oct. 22 on TheSixFifty.com, a sister publication of Palo Alto Online, covering what to eat, see and do in Silicon Valley.