Study: A systematic review of human behavioral response to wildfire smoke (DOI: 10.1088/1748-9326/ae20ae)
EXPERT Q&A
With wildfires growing in size, frequency and intensity, more and more people are being exposed to their smoke, sometimes thousands of miles from the flames.
In the wake of recent historic fires in Canada and the United States, a growing body of research is showing how harmful that smoke can be to human health. But less is known about how humans behave in response to smoke, said Paige Fischer, associate professor at the University of Michigan School for Environment and Sustainability. And understanding how and when people make decisions to limit their smoke exposure is key to developing programs and policies that can best support and augment individual choices, she said.
That's why a doctoral student in Fischer's research group, Caroline Beckman, led the first systematic review of available scientific literature on the subject. The review, published in the journal Environmental Research Letters, reveals opportunities for this developing field and is helping steer the U-M team's ongoing work called the Xtreme Smoke Project, which is supported by a NASA grant.
Why is it important to study human behavioral responses to wildfire smoke?
Beckman: Smoke is an incredibly hot topic in research and news coverage right now, particularly in the U.S., because of the explosion of really extreme, catastrophic fires that we've seen in the last five or so years. Those have come with a lot of smoke that is impacting people, not just in the areas where the fire is happening, but it can spread really far from the source.
With climate change and the fuel loads in our forests, both in the U.S. and globally, we're going to live in a world that is smokier. The more research that comes out, the more we know that smoke in any amount is really bad for human health. That's in the short term and in the long term, where it exacerbates heart and lung conditions. New research is also linking it to dementia. Ultimately, we'll see excess mortality that is attributable to wildfire smoke.
Human behavior is one of the best tools in our toolbox to reduce exposure to that growing threat. So, given that we're going to have smoke, our focus really needs to be on how we ensure that people are capable of doing something to reduce their exposure for their health, their family's health and their community health.
Fischer: We're not expecting individual action to be the only way to protect people from smoke. But to design programs and different kinds of policy interventions, we first need to understand under what conditions are people going to take action to protect themselves on their own, if at all. Knowing what motivates people to take the initiative to protect themselves-like, how bad does smoke have to be for people to take initiative?-that will help us understand when policy needs to intervene and how.
This is a newer field, with the majority of its research published starting in 2014. In your review, you identified where some key gaps in the research are after about a decade. What do you think are the biggest blind spots currently?
Beckman: There's a lot of opportunity as this topic becomes more developed and we see future work being really important. For me, there are three big pieces.
One is simply where these papers are coming from. Almost all of the literature that we were looking at is from North America, even though we know that fires are a global problem happening everywhere. That probably reflects the research infrastructure and capability of Canada and the U.S. Australia also was pretty well represented.
The second is that we know from the public health and medical side of things that smoke is really harmful to everyone. But it's particularly bad for certain folks: younger folks, older folks, people with existing heart or lung medical conditions, and people who are simply more exposed to smoke by nature of where they live or what they do. Going in, I expected a lot more of the focus in the literature to be on those sensitive or vulnerable populations. But, because this is such a new body of literature, that hasn't been a huge focus yet.
Then the last one has to do with the models we used to break down our findings based on the cognitive processes people use to make decisions. Those have external contextual factors-like where you live, what you do for work and other demographic factors-and they also have a social piece. We know that networks and social norms-how we think people should behave and how we think people around us want us to behave-are really impactful on our decisions. The blind spot is that a lot of the research called out the importance of those social influences, but it wasn't a main focus of hardly any of the studies that we looked at.
Can you give an example of a social element?
Beckman: Mask wearing is one example. There are specific norms around mask wearing, about when and where it's acceptable to do it, and some of that is carried over from COVID and, more broadly, infectious disease. But is that going to change when we have contexts where it might become more normal to see people walking around in masks on a smoky day? And how will that influence things?
You mentioned you used models of decision-making as a way to ground your analysis of the literature. What are those models and how are they helpful?
Beckman: We needed to impose some structure on a really nascent literature. This literature is very applied and emergent. So we wanted to bring in some of the lineage of public health, natural hazards research and many other fields that have existing models of how people interact with their environment.
When we think about human behavior, it's not, "I receive an environmental cue, and thus I decide." There are all these intervening pieces coming from human psychology, cognitive processing, cultural factors and the social elements we talked about. These all come into play when you see an environmental cue like smoke outside your window, and have to make some decision about whether you choose to protect yourself or just go about your day.
Those models are a way to create linkages between environment and behavior. They bring a little more specificity into what are the pieces of decision-making that we can specifically call out and explore.
