Northern California Science Writers Association

Wildfire smoke and public health: research updates for reporters

By Elyse DeFranco

Wildfire smoke has become synonymous with summer in the West, and increasingly across the country. As communities grapple with wide-ranging impacts on public health, science journalists need to stay informed on the latest research.

At the virtual ScienceWriters2021 conference, Sheryl Magzamen of Colorado State University and the Colorado School of Public Health shared findings from several recent studies into the epidemiological effects of smoke.

The first study, led by Magzamen, focused on the front range of Colorado. Her team sought to differentiate health effects from exposure to local vs. long-range smoke. The mountainous region often acts as a catchment for smoke wafting in from California and the Pacific Northwest. It also contains 80% of Colorado’s population.

The researchers quantified smoke intensity and collected data on hospitalization rates from 2010 to 2015. They found significant increases in hospitalization rates for ischemic heart disease, respiratory asthma, and acute bronchitis following smoke exposure. Mortality rates for asthma and cardiac arrest also increased.

Although previous studies have suggested that smoke from distant fires has higher toxicity levels, the researchers ran into some counterintuitive data in Colorado: There were fewer hospitalizations from asthma when smoke from local fires affected air quality. That could arise from people avoiding the areas near active burns, they hypothesize.

The second study (in preparation), by Sheena Martenies of the University of Illinois, examined how the overlapping risks of COVID-19 and smoke exposure impacted mortality rates in 2020. Although 2020 was Colorado’s worst year on record for wildfires, preliminary results showed another counterintuitive result: a 12% decrease in the death rate. The twin risks of the pandemic and the increase in local smoke may have driven many people inside their homes, shielding them from both smoke exposure and COVID transmission, the team believes.

The third study (in press), by Bonni Beaupied, a DVM student at Colorado State University, looked at the effects of smoke exposure and milk production in dairy cows. The researchers theorized that cows could potentially act as sentinel species for unexamined human health impacts. Inflammation causes dairy cows to produce less milk, which is a known consequence of higher temperatures. But the study showed that exposure to harmful PM 2.5 particles in smoke actually had a stronger impact than heat on reducing milk output from cows.

Magzamen wrapped up her informative session by sharing some tips for what journalists should look for when assessing studies on smoke-related health impacts. Beyond particulate matter (PM 2.5 levels), the source of the smoke is important to consider, as well as the duration of exposure. Scientists are also debating the nature of how wildfire smoke is defined and quantified, with a range of measurement methods including satellite data, chemical transport models, and data from monitoring stations. Smoke moves in unpredictable ways, following local topography and wind patterns. Magzamen reported some progress toward hyper-local, low-cost monitors that could provide more accurate measurements.

As climate change fuels increasingly large and long-lived wildfires, reporting on the rapidly developing research on health impacts associated with smoke exposure is critical for helping the public make informed decisions.

“Unlike when we talk about catalytic converters, or scrubbers on point sources, action to limit the impacts of wildfire smoke is required by people rather than at the source,” Magzamen said. “We're really relying on the media to communicate messages on smoke and health.”

Elyse DeFranco is a science and environmental journalist in the San Francisco Bay Area. She earned an M.S. in ecology and environmental science at the University of Maine, and she is pursuing an M.S. in Science Communication at UC Santa Cruz.

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