This “smoke season” thing: Is it a thing?
Busch Isaksen has spent most of her 25-year environmental health career focused on conditions like extreme heat, but 2017’s smoke season pushed her into the world of wildfire.
“2017 marks this new era … with statewide smoke events of significant duration to where it affected your ability to go about your daily routine,” she says. “It's definitely one of those exposures that's included in the long list of potential things that climate change is going to influence, but you're always surprised, I think, when it actually happens.”
Dhammapala says the most common question he gets is whether seasonal smoke is a “new normal.”
“We've not provided a specific or a concrete answer because we simply don't know,” he says. “There's a lot of variability in how the fire season will shape up.… Just because the last two smoke seasons were bad doesn't mean it's going to be three in a row, and so far thankfully we are OK,” Dhammapala told us in the first week of August. “It’s looking a bit better this year so far than the last few. But that doesn't mean we're out of the woods yet.”
This year wasn’t too bad for Washington fires. Is that why we were in the clear?
We spoke with a number of fire analysts at the end of the month about why the season didn’t get as bad as some people expected, and how interannual variability means we can experience lower-fire years even as the climate warms.
No matter how much acreage burns in a fire season, the things that really amplify smoke are influenced by the collection of near-term atmospheric conditions — basically, weather. Trends in weather over time become what we think of as the climate.
“We had a lot more acres burn in 2015 than last year, but we had the worst smoke last year,” Dhammapala says. “And the reason for that is, it depends on where the fires are ... and what the winds are doing to transport the smoke, which is generally a localized or regional meteorology-driven issue. Smoke intrusions are driven by a meteorology that changes all the time, and it's hard to forecast the whole season of meteorology. Three days is kind of as much as we could trust forecasts … [and] be reasonably confident of what the smoke impacts are going to be.”
Many of the variables that worsen fire also worsen smoke. Beyond the location of source fire and type of fuel burned, “the typical conditions that increase the amount of smoke are heat, low humidities, [low moisture] and stronger winds [that] typically fan the flames,” Dhammapala says. “But winds are kind of a double-edged sword, because it helps fire spread, but it also dilutes plumes. [If a fire has] already grown ... then once the winds die down, a whole lot of smoke starts accumulating and won't disperse.”
The presence of high-pressure weather systems, which warm and dry the air alongside reduced wind, can also trap smoke.
Dhammapala says that he’s noticed people seem more alert or anxious about smoke over the past five years.
“Our websites are straining whenever there's a smoke event in Western Washington — we're just unable to keep up with the volume of traffic,” he says. “Which is kind of a good problem to have — it's people looking for data, looking to know what to do and how to structure their lives.”
While he’s not personally very sensitive to it, it’s always on his mind. “I'm very aware of it,” he says. “I spot it all the time, I know when I'm being impacted, and I have to bear in mind that I shouldn't spend too much time in some of the smoke. Like, last year, I had to very proactively decide and plan out how long I was going to be outdoors — not because I had any adverse reactions personally but, you know, practicing what you preach is important and all the health-related consequences we've learned about? Just because you don't see it unfolding before your eyes doesn't mean it's not happening.”
When smoke gets bad in Seattle, where does it come from? I’ve heard Washington, British Columbia, California and Siberia (which sounds nuts).
Smoke comes at Seattle from many different angles: Siberia, British Columbia, Alaska, and far beyond, in addition to the plumes blowing over from Eastern Washington or burning in our own backyard.
“If it's coming from six different areas it's kind of hard to quantify and qualify it, so that affects the composition of smoke, as well as what you can actually do about it,” Busch Isaksen says.
But, generally, faraway fires aren’t as much of a health risk.
“There have been a few detections of smoke from as far away as Siberia, but [...] in very low concentrations, because once it travels that far, it's diluted and tends to spread wide,” Dhammapala says. “[It’s] not the kind of smoke that will cause your lungs to burn and send people to the emergency room because of asthma attacks. You might be able to smell it, but those are not the big concerns. The nearer the source, the worse the impact.”
In practice, that means smoke from Alaska isn’t as big of a concern as smoke from B.C. — which “was a big contributor [the previous two years], but it also was superimposed on top of some smoke from our own Cascades fires.”
How big of a health risk is smoke?
Health researchers are concerned about all kinds of air pollution. But where everyday pollution from traffic or construction is ambient, wildfire creates short bursts of significant exposure — and what that means for long-term health isn’t yet clear. Since people began studying smoke, we’ve only accumulated a small sample size of statewide wildfire data. That impacts the quality of the available research into whether smoke itself, or the concentration of it, are attributable to health issues.
“There is a lot of research left to do. Nationwide there are very few wildfire smoke related health studies that have been conducted,” Busch Isaksen says.
Dr. Coralynn Sack agrees. “[Wildfire smoke] is an emerging research interest — it’s really just coming out,” she says. “We don’t really have too many answers about chronic exposures.”
But researchers like Busch Isaksen and her collaborator, Dr. Nicole Errett, are at the vanguard of helping the state find answers. After receiving questions from people at health-focused agencies around the state about what messages they should be sharing with the public about risk and finding the data lacking, Busch Isaksen and Errett organized a forum for discussing concerns, formalizing the health community’s knowledge of smoke impacts and figuring out where the big gaps in knowledge were.
Last October, the duo got the forum off the ground as the Wildfire Smoke Risk Communications Stakeholder Synthesis Symposium. Seventy-six representatives from more than 30 organizations — predominantly universities, clean air groups and public health agencies — convened to discuss the 2017 and 2018 fire seasons and future research opportunities. Through the symposium and available research, it’s become clear that some populations — the very young, old, ill and those who work or live outside — are more susceptible to short-term smoke impacts than others as a result of the way smoke is structured and interacts with our bodies.
How dangerous wildfire smoke is often comes down to its components: It’s a mixture of a few different things, Sack says.
“A lot of it is water vapor and carbon dioxide, but there’s also byproducts of combustion, which include particulate matter, smaller compounds like acryline, secondary pollutants like ozone — a whole host of different compounds and chemicals,” she says.
The fine particulate matter presents the biggest concern to air pollution and environmental health experts, particularly PM 2.5, the most commonly monitored pollutant on Earth. These particles are smaller than 2.5 micrometers in diameter (the diameter of human hair is about 70 micrometers). For context: In Washington, Dhammapala says there are about 15 monitors tracking ozone and 65 tracking PM 2.5.
“It's harder to expire it out or exhale it out, so it lodges deep in your lungs and produces inflammatory response,” Busch Isaksen says.
Depending on where fires occur, they may produce smoke with more dangerous chemical compositions.
“There are certain woods that are more toxic, for lack of better term, to health than others; and so you add in then whether or not these fires have also consumed structures and are then emitting flame retardants and other kinds of chemicals that would be hazardous to human health, or they're burning acreage where there are legacy pollutants like pesticide use and things like that,” Busch Isaksen says.
While the chemicals in smoke and particles themselves can irritate skin and eyes, particles become especially problematic when they enter people’s bodies and impact breathing systems and the heart. Sack and Busch Isaksen both say wildfire smoke is especially dangerous for the lungs, especially in people with preexisting lung illnesses like asthma, emphysema or chronic obstructive pulmonary disease (COPD).
“For the pulmonary outcome, it's exacerbating existing underlying health conditions like asthma or COPD, where you already have a restrictive air flow,” Busch Isaksen says. “For the cardiovascular health outcomes, the research is a little less clear: Air pollution affects inflammation within your [body] and that can lead to impacts on your cardiovascular health. That's something that's very well demonstrated in long-term air pollution and health studies at lower levels. But what's uncertain is this short-term, very high exposure and health outcome” associated with wildfire smoke.
As a pulmonologist, Sack treats people who feel acute impacts of smoke. “My patients with preexisting lung diseases are the ones I really hear complaining of the most symptoms,” she says. “Most people feel irritation of their eyes and throat, if exposed to higher levels of smoke. … What we’re really worried about is exacerbation of lung diseases or worsening respiratory status.”
Those who work outside by necessity — agricultural workers, firefighters, construction workers and more — can be at heightened risk because they spend long periods outdoors exerting themselves, breathing more air than people at rest. “There is a definite concern in communities where their agricultural workers are out in the field and they're harvesting at the time of wildfire smoke exposure,” Busch Isaksen says.
However, even people who work indoors can experience negative smoke impacts if offices have poor air filters. Bike commuters will feel the dual impacts of traffic and wildfire smoke.
When wildfire smoke gets as bad as it did in 2017 and 2018, Busch Isaksen says, “it's not just those that are sensitive” that suffer. “When you get to concentrations like we were seeing last summer, everybody ought to not be breathing it — everybody should be changing their behaviors to reduce that risk or reduce their exposure.”
But the data we have is incomplete, for many reasons. Some experts have found that work conditions impact whether workers choose to endure smoke impacts or report symptoms; and the report from Busch Isaksen's smoke symposium states agricultural workers’ socioeconomic status can prevent them from speaking up about health concerns. Experts also rely on medical records to track health concerns: This means events like higher respiratory mortality on wildfire days can be tracked, but lower-level impacts that don’t trigger a hospital visit will go unnoticed. That can include everything from diminished mental health and wellness to lowered productivity.
To make things more difficult, it’s hard to study health impacts of seasonal events, Sack says.
“Wildfire smoke events are usually smoke events that last a few days… [which] makes it hard to estimate, what does long-term exposure mean?” she says. The way fire seasons are developing, however, means we might have more opportunities for research.
“Definitely as seasons are getting longer and occurring for long parts of the summer-slash-fall, [data] will be easier to define — which is maybe exciting, but also maybe a bit disheartening, ” Sack says.
Geographically, environmental health practitioners like Busch Isaksen are most concerned about Eastern Washington smoke exposures.
“East of the mountains, they've been enduring wildfire smoke and wildfires in close proximity for a long time,” Busch Isaksen says. “But the added transboundary pollution is definitely influencing and impacting them in a way that is adding to their existing hardship.”
So how can I protect myself?
Doctors like Sack see a lot of people concerned about smoke who are unsure of how to protect themselves.
She thinks the most important things are for people to find ways to feel a sense of ownership and control over their situation, “because I think that can be what's the scariest for a lot of people: They see bad quality air and they feel helpless, and don't know what they can do to prevent exposure or harmful effects.”
Busch Isaksen believes that personal preparedness is key to safe smoke seasons. “We have interventions; it’s just whether people will do it,” she says.
The number one thing you can do, Busch Isaksen says, is to go indoors. “Your exposure is definitely reduced when you go indoors — that’s been demonstrated,” she says. But that won’t eliminate all risk — a lot depends on the quality of the building you’re in, which owners have more control over. Renters and owners should check whether a building has a leaky filtration system, or no HVAC (heating, ventilation and air conditioning) system at all: Seattle is the least air-conditioned major metro area in the country, which pushed the city of Seattle to offer HVAC-equipped smoke havens to citizens this summer.
While maintained HVAC systems are the workhorses of smoke resiliency, in-room air purifiers and filters with HEPA (high efficiency particulate air) filters can also be important pieces of your smoke toolkit. Rather than ventilating air and pushing it back outside, in-room filters extract particulates from the air.
“If you don't have [good building defenses], do you have an in-room HEPA filter that you have running in one dedicated room? ... Even those do-it-yourself units, the box fans with high efficiency furnace filter on the back, greatly reduce the particulates in your home. We promote the use of those,” Busch Isaksen says, especially for people who can’t afford air purifiers.
Face masks have become especially trendy in smoky months, with hardware stores frequently selling out of them.
“Last summer when I had to walk my dog, I put one of those things on and took my dog outside,” Busch Isaksen says. “We didn’t take the long walk, but sometimes you’ve got to go outside.”
But the masks aren’t for everyone, and they don’t offer full protection.
“N-95 masks is one intervention that people just kind of throw out there, but it’s not appropriate for everyone, and it does matter if you fit it properly to your face,” Busch Isaksen says. “The more important message that we came out [of our symposium with] is to try and reduce your exposure in other ways and, if you have to go out, using one of these properly fit masks. But don't put it on and [think you can] ride your bike and enjoy the outdoors!”
While most people benefit by wearing masks, people with existing respiratory problems may find their breathing worsened by them.
To identify when to use a mask, or go outside at all, Busch Isaksen recommends consulting available air quality information, like Dhammapala’s smoke blog or the state Department of Health’s smoke and air map.
At a certain point, people with respiratory illnesses may need to consider evacuation, Sack says. “Obviously you have to balance the effects of increased risk with total disruption of your life, and that’s a hard balance to figure out,” she says, noting that doctors can help personalize health plans ahead of these events.
“It’s important for people to just listen to their bodies,” she says. “If they’re outside experiencing unpleasant symptoms, they should stop doing it. But if they’re feeling OK and the air quality is in a good range or moderate, then they can probably continue to go about activities.”
Some people have invested in personal air monitors from companies like Purple Air, which offer hyperlocal air quality alerts in real time. When calibrated correctly, they can help people make decisions about whether it’s OK to do things like send their kids to school or go for a run. But “the low-cost sensors, as they’re known, are low cost for a reason,” Dhammapala says.
Low-cost sensors aren’t going to give people as high-quality data as dedicated agency-run sensors, like the short-term sensors deployed during fire events. But for some regions, like the Methow Valley, where smoke is a year-round event, it can be a way to help people take ownership of their air.
Busch Isaksen is part of a group helping Okanogan County figure out how to set up an air quality network. The team set up 20 different Purple Air monitors for them, with one of Busch Isaksen’s students living in the Methow Valley for a summer to help facilitate that. The monitors are maintained by clean air ambassadors in the Methow Clean Air Agency.
“We're hoping that the community is empowered … that they can make decisions about what their own risk is and how to reduce their exposure … not just [to] wildfire smoke but smoke from prescribed burns and smoke from wood fires and things like that during the winter time. They can make decisions based on their proximity,” Busch Isaksen says.
Ultimately, Sack says, the burden of responsibility can’t rest solely with individuals when it comes to managing their smoke impacts: “You have to talk about climate change and you have to talk about policy. We don’t want to just patch over [smoke problems] by learning how to adapt to smoke — although we probably will have to do that. We want to address the underlying causes.”
Update: We added language to clarify Dr. Sack's professional affiliations; and to specify the types of air sensors discussed in the article.