climate change

Indigenous People in South America Are Twice as Likely to Die from Wildfires than Broader Population

A new study suggests that regions in Peru, Bolivia, and Brazil are hotspots for smoke exposure, with mortality rates rising to as high as six times that of the general population.

Indigenous people in the Amazon Basin are twice as likely to die prematurely from smoke exposure due to wildfires than the broader South American population, according to a new study co-authored by a School of Public Health researcher. 

Published in the journal Environmental Research Health, the study identified regions in Peru, Bolivia and Brazil as particular hotspots for smoke exposure, with mortality rates rising to as high as six times that of the general population.

The results show that smoke from wildfires in South America account for approximately 12,000 premature deaths every year from 2014 to 2019, with approximately 230 of these deaths occurring in Indigenous territories. Exposure to harmful smoke particles is much higher during the Amazonian dry season—from August to November each year—when wildfires more than double the increase in PM_2.5 concentrations.

“This research highlights the serious health burden of landscape fires, both to communities experiencing the fires, and the wider regional impacts that these fires can have on regional air quality,” says study coauthor Jonathan Buonocore, assistant professor of environmental health. “With risk of wildfires increasing in areas that will see more drought with climate change, events such as these may become more and more common as the climate continues to change.”

Previous research in the field has focused on the health impacts of countries on larger scales, or is heavily reliant on hospital admission data. This data does not accurately capture the impact on people living in indigenous territories, as they are often located much closer to the fires, are exposed to smoke particles for longer periods of time, and lack access to appropriate medical care, hygiene materials, and clean water. 

“While Indigenous territories account for relatively few fires in the Amazon Basin, our research shows that the people living in these territories experience significantly greater health risks from smoke particles, compared to the general population,” says study lead author Eimy Bonilla, currently a postdoctoral fellow at Howard University, and a PhD student in environmental science and engineering at Harvard University’s John A. Paulson School of Engineering and Applied Sciences at the time of the study.

The study uses a combination of atmospheric chemical transport models and an updated concentration response function to estimate the rate of premature mortality for Indigenous populations exposed to high concentrations of PM_2.5.

In recent years, the rate of biomass burning in South America has surged, driven by forest degradation due to human activity (such as mining, logging, and agricultural land use) as well as variations in climate conditions. Wildfires release tiny smoke particles called PM_2.5, which are known to significantly contribute to aerosol concentrations and negatively impact human health. Exposure to these particles can result in cardiovascular and respiratory diseases, cancer, premature births, metabolic dysfunction and other physiological symptoms. Smoke particles from biomass burning in the Amazon Basin travel great distances, affecting air quality across several countries in South America. 

“These fires are having a disproportionate impact on people living in Indigenous territories. With longer exposure times, and limited access to medical attention, Indigenous populations are at much greater risk of death from fires,” says Bonilla. “We recommend that governments provide financial assistance to monitor air quality in these regions, supplying low-cost sensors to study the impact of short- and long-term exposure to the smoke.”