Stanford researchers explore how people respond to wildfire smoke

Interviews with Northern California residents reveal that social norms and social support are essential for understanding protective health behaviors during wildfire smoke events – information that could be leveraged to improve public health outcomes.

As wildfires become commonplace in the western U.S. and around the world, checking the daily air quality warning has become as routine as checking the weather. But what people do with that data – whether it drives them to slip on a mask before stepping outside or seal up their homes against smoke – is not always straightforward or rational, according to new Stanford research.

Using the framework they created for this study, the researchers aim to assess the effects of low-cost individual and household interventions to reduce the impacts of wildfire smoke in at-risk communities in San Mateo and Santa Clara counties. Wong-Parodi along with Stanford researchers Stephanie Fischer and Natalie Herbert are pictured planning recruitment strategy with Ortensia Lopez of El Concilio of San Mateo and Violet Saena of Climate Resilient Communities. (Image credit: Tom Casciato)

In a case study of Northern California residents, Stanford researchers explored the psychological factors and social processes that drive responses to wildfire smoke. The research, which ultimately aims to uncover approaches for helping people better protect themselves, shows that social norms and social support are essential for understanding protective health actions during wildfire smoke events. The findings appeared this month in the journal Climate Risk Management.

“It’s important to understand how people behave so that public health communications professionals can potentially intervene and promote safer behavior that mitigates risk,” said lead study author Francisca Santana, a PhD student in the Emmett Interdisciplinary Program in Environment and Resources (E-IPER). “This kind of qualitative work is a first step so that we can learn how people are using information and interacting to make decisions. We can then look at where there might be leverage points or opportunities to promote more protective behavior.”

Exposure to wildfire smoke can irritate the lungs, cause inflammation, impact the immune system and increase susceptibility to lung infections, including the virus that causes COVID-19, according to the Centers for Disease Control and Prevention. While other studies have examined how people respond to evacuation orders, little has been done to understand what’s happening with wildfire smoke exposure if people don’t – or can’t – leave the area, according to senior study author Gabrielle Wong-Parodi, an assistant professor of Earth system science at Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth).

“It resonated with me, the things that people were doing to try to protect themselves in the absence of access to effective ways to reduce their wildfire smoke exposure,” Wong-Parodi said, referring to a resident who breathed through a wet bandana in an attempt to filter out toxic smoke particles. “It’s urgent that we come up with strategies that are realistic for what people are going through.”

Study authors Santana and David Gonzalez, who worked on the study as a PhD student at Stanford, interviewed residents across age, race and income demographics who were affected by wildfire smoke from the 2018 Camp Fire that destroyed Paradise, California, and subsequent fires in 2019 in Fresno, Santa Clara and Sacramento counties.

They found that individuals responded to wildfire smoke events in three main ways: interpreting information together, protecting vulnerable others and questioning protective actions. Their responses were influenced not only by the Air Quality Index (AQI) but also by what they were personally experiencing – whether they smelled, saw or tasted smoke in the air.

Just as important were the social factors at play, the researchers found. “Social norms and social support were really influencing how people chose to act on their perceptions of threat,” Santana said. “For example, a lot of people talked about observing others wearing masks, and in some cases that observation was enough for them to act by wearing a mask themselves.”

Their discussions revealed that the shared rules or standards of behavior within a social group – social norms – were a common pathway driving behavior change, in addition to the act of assisting or comforting others within your social group – social support.

“There were only a handful of people who described looking at the AQI and then changing their behavior based on just that – it was almost always a conversation they were having with one another,” Santana said. “It was very much a social exercise of making sense of limited information or information that was not at the right scale for their community.”

The study provides a framework for better understanding wildfire smoke responses by examining social processes while acknowledging that cultural and political contexts, as well as factors like demographics, health status and previous exposure to smoke and air pollution, may also influence individual behaviors.

In the western U.S., climate change has contributed to the risk and extent of wildfires, bringing smoke to regions like the Bay Area, which has historically been less affected than the rest of the state. In some cases, the researchers found that residents were unable to protect themselves because they couldn’t access N95 masks or air purifiers or properly seal their homes.

“This research is also important for epidemiologists trying to understand how wildfire smoke affects health,” said Gonzalez, who is now a postdoctoral researcher at the University of California, Berkeley. “This can help us to look at disparities in who’s exposed to smoke and whether that leads to poorer health for some populations.”

As these events become more common, there could be an opportunity to find policy synergies that help prepare communities for future smoke events, according to the co-authors. For example, programs that are designed to improve household comfort and increase energy efficiency could also include measures to reduce smoke intrusion during wildfire smoke events, Wong-Parodi suggested.

Some of the interviews revealed that residents simply didn’t know what to do while experiencing a novel extreme event. But even that revealed how processing uncertainty is a social exercise, not just a cognitive one.

“This piece shows that social norms may be an effective lever for encouraging the pro-health change that we’d like to see,” Wong-Parodi said. “That is actually a really promising sign for thinking about how to adapt and mitigate our risk as we’re facing increasing threats from climate change.”

Wong-Parodi is also a center fellow at the Stanford Woods Institute for the Environment. Stanford research coordinator Stephanie Fischer, BS, BA ’19, and Earth systems master’s student Jessica Mi helped conduct interviews for the study.

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Media Contacts

Francisca Santana, School of Earth, Energy & Environmental Sciences: fsantana@stanford.edu

Gabrielle Wong-Parodi, School of Earth, Energy & Environmental Sciences: (650) 725-6457; gwongpar@stanford.edu

Danielle Torrent Tucker, School of Earth, Energy & Environmental Sciences: (650) 497-9541; dttucker@stanford.edu