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One of the wildfires nearing a California city in 2020. Photo courtesy of Unsplash/Levan Badzgaradze.

Smoke and Stroke: Investigating the Long-term Effects on Wildfires on Heart Health

Joshua Fu, a Chancellor’s Professor, a John D. Tickle Professor, and a James G. Gibson Professor in the Department of Civil and Environmental Engineering, collaborated in securing a $3.7 million award to research the long-term connection between wildfire smoke and cardiovascular disease (CVD).

The grant, awarded by the National Institutes of Health (NIH), will support a five-year research project co-led by Fu and Professor Yang Liu of Emory University.

“Wildfires are not new events,” said Fu. “But now, due to climate change, they are larger, more intense, and more frequent. This is why we need to understand the health effects of long-term smoke exposure.”

Fu has a long history of researching the effects of climate change on air quality and human health; he helped improve the Community Multiscale Air Quality Modeling System (CMAQ), which the US Environmental Protection Agency (EPA) uses to model air quality and atmospheric chemistry.

Past studies have drawn a clear connection between low air quality and CVD, which includes heart attacks, strokes, heart failure, and atrial fibrillation, and the particles and gases produced by wildfires are major contributors.

“In a decade-long study, we found that when a larger area burns, the smoke stays in the atmosphere a longer time,” said Fu. “The smoke from recent fires in the western US, especially in the 2020s, is reaching cities on the East Coast.”

Smoke carries many harmful substances, some of which have been definitively linked to CVD. For example, as materials burn, they create particulate matter measuring less than 2.5 micrometers (known as PM2.5). If inhaled, PM2.5 can be embedded in the smallest parts of the lungs and may even enter the bloodstream, impacting human cardiovascular health.

Smoke becomes increasingly toxic as additional materials burn, and as people in the Western US have been building homes closer to forests, synthetic materials and heavy metals are getting caught up in the flames.

“Houses contain a lot of toxins, like plastic, metals, and often formaldehyde,” said Fu. “Those aerial toxins become a chronic threat for downwind communities.”

The health risks of many of those toxins have not been studied, either at the acute (immediate) or chronic (long-term) scale. That is one task Fu is hoping to tackle.

Fu and Liu’s team will first correlate EPA data gathered by CMAQ from 2001 to 2020 to estimate the daily amounts of smoke-derived pollutants in both smoke and “non-smoke” air.

CMAQ will then predict potential air pollutant levels based on future climate change projections consistent with scenarios developed by the Intergovernmental Panel on Climate Change (IPCC).

As new fires occur over the next five years, the team will gather both air quality data and patient data. Doctors on the Emory team will gather records of emergency room and primary care admissions for CVD in areas where wildfires are occurring.

“The use of patient data Is one of the strong points of this proposal,” said Fu. “We won’t be relying on estimates from models, but rather seeing the actual rates of CVD. This fine-tuned data will make our predictions more robust.”

The main thrust of the study will be plugging disease, future climate, and air pollution data into CMAQ and other models to project air quality and CVD rates from the year 2050 to 2100. Using CMAQ, Fu’s team will also be able to make recommendations for policies and techniques that could improve future air quality.

Fu hopes that this study will result in more effective emergency responses to wildfires, such as evacuations and early medical interventions.

“We definitely appreciate that NIH is providing this funding for us,” he said. “We can use it to raise public awareness about wildfire health effects, and not just for western states. Wildfires happen in our eastern and southeastern states as well.”