Preprints
https://doi.org/10.5194/egusphere-2026-1614
https://doi.org/10.5194/egusphere-2026-1614
02 Apr 2026
 | 02 Apr 2026
Status: this preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).

Impacts of Droughts on Biomass Burning Emissions, Air Quality, and Public Health in the Amazon

Leo T. H. Ng, Jia Mao, Xueying Liu, Shixian Zhai, Dominic Fawcett, Stephen Sitch, Luiz E. O. C. Aragao, and Amos P. K. Tai

Abstract. Wildfires in the Amazon, increasingly influenced by climate variability and anthropogenic activities, pose severe environmental and health challenges. While drought events amplify fire activity and emissions, the cascading effects of droughts and deforestation on air quality and health remain underexplored. This study addresses this gap by combining satellite observations of fire activities with the Global Fire Emissions Database (GFEDv4s) and the chemical transport model, GEOS-Chem High Performance (GCHP) to quantify the impacts of droughts and deforestation on fire emissions, air quality, and health risks from 2010 to 2015. “Fire-on” and “fire-off” simulation reveal that biomass burning dominates dry-season (July–November) air quality, contributing 50 % to regional CO and PM2.5 and 33 % for ozone in non-drought years. These contributions increase to 60–80 % for CO and PM2.5 and 50 % for ozone during drought years. Significant correlations between pollutant levels and drought intensity reflect a climate-driven amplification of fire impacts. Using the Global Exposure Mortality Model (GEMM) and exposure-response relations, we estimate that fire-induced PM2.5 and ozone increase premature mortality by 6.0 % and 18.6 % in non-drought years, which rise to 8.9 % and 24.4 % during drought years. These findings underscore the critical roles of droughts in exacerbating fire emissions and health risks, even under stable deforestation rates. This study highlights the urgent need for integrated wildfire management and climate adaptation strategies to protect public health and achieve sustainability goals.

Competing interests: At least one of the (co-)authors is a member of the editorial board of Atmospheric Chemistry and Physics.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.
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Leo T. H. Ng, Jia Mao, Xueying Liu, Shixian Zhai, Dominic Fawcett, Stephen Sitch, Luiz E. O. C. Aragao, and Amos P. K. Tai

Status: open (until 14 May 2026)

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Leo T. H. Ng, Jia Mao, Xueying Liu, Shixian Zhai, Dominic Fawcett, Stephen Sitch, Luiz E. O. C. Aragao, and Amos P. K. Tai
Leo T. H. Ng, Jia Mao, Xueying Liu, Shixian Zhai, Dominic Fawcett, Stephen Sitch, Luiz E. O. C. Aragao, and Amos P. K. Tai
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Short summary
Wildfires in the Amazon worsen air pollution and threaten public health, yet the role of droughts in amplifying these effects is poorly understood. Using satellite data and atmospheric modeling, we assessed how droughts intensified fire emissions and pollution in the Brazilian Amazon from 2010–2015. During drought years, fires contributed up to 80 % of harmful particles and raised premature deaths by up to 24 %. These results stress the need for fire management that accounts for drought risks.
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