Across Southeast Asia, fires are used for agricultural management and forest clearance. They are major sources of noxious pollutants that often severely degrade the region’s air quality. Although exposure to these pollutants has been associated with increased morbidity and mortality rates in other areas and studies have shown that reducing air pollution has health and climate benefits, few studies have quantified the air quality and health impacts of fires in mainland Southeast Asia.
To help fill this gap, Reddington et al. used observations as well as global and regional air quality models to investigate the impacts of vegetation and forest fires in mainland Southeast Asia (Cambodia, Laos, Myanmar, Myanmar, Thailand, and Vietnam) and southeastern China. For their analysis, the researchers used a global air quality model to compare three separate fire emission data sets, plus a regional model and local poverty proxy data, to assess the benefits of eliminating regional fire emissions on Southeast Asian air quality and public health.
The results indicate that eliminating vegetation and forest fires could substantially improve the air quality in the region, reducing public exposure to tiny, unhealthy particulates by 16% in mainland Southeast Asia and 2% in southeastern China. Ozone exposure would likewise be reduced in these areas by 9% and 2%, respectively. The study also shows that fire-derived particulates disproportionately affect poorer Southeast Asian populations; in particular, two regions in western Myanmar and northern Laos showed especially high poverty levels that coincide with relatively high exposures to these airborne particles.
The findings strongly suggest that decreasing exposure to emissions from fires would result in substantial public health benefits in the region, including averting more than 59,000 premature deaths per year due to airborne particulates. The authors calculated that the overall benefit to public health in mainland Southeast Asia would be comparable to eliminating all the region’s industrial emissions.
Since reducing fires lit for agricultural management and forest clearance would likely yield rapid and substantial improvements in air quality, the authors argue that preventing deliberate vegetation and forest fires should be viewed as a high public health priority for the region. Considering these fires in addition to standard pollution emission sources will clearly be necessary for policymakers to develop effective emission control policies across Southeast Asia. (GeoHealth, https://doi.org/10.1029/2021GH000418, 2021)
—Terri Cook, Science Writer