Aerosol Emissions from Biomass Burning in Southeast Asia

Biomass burning in Southeast Asia arises predominantly from deforestation, land‐clearing for agriculture and recurrent peatland fires. These combustion processes emit vast quantities of primary aerosols, including organic carbon, black carbon and inorganic salts, which evolve through atmospheric oxidation into secondary organic aerosol. The region’s seasonal fire activity, often exacerbated by El Niño–induced drought, produces persistent haze that travels across national boundaries, degrading air quality in urban centres and rural communities alike. Aerosol optical depth peaks during the dry season, reflecting dense smoke plumes lofted from peat and forest fires. These particles exert a dual influence on climate, directly by scattering and absorbing solar radiation and indirectly by modifying cloud microphysics, thereby altering precipitation patterns. The heterogeneous nature of peat soils means that smouldering combustion dominates, generating high emissions of brown carbon and trace gases. Transboundary transport compounds health burdens through elevated PM₂.₅ concentrations that have been linked to respiratory and cardiovascular illness. Understanding the factors controlling fire occurrence, emission characteristics and plume dispersion is essential both for regional air‐quality management and for global assessments of carbon budgets and climate forcing.

Research from Nature Portfolio

A recent investigation in a major urban agglomeration revealed a two‐way causal relationship between ground‐level aerosol loadings and land surface temperature. By applying information‐theoretic metrics to long‐term observations, it demonstrated that transboundary smoke emissions significantly drive daytime surface warming, while rising nocturnal temperatures promote the retention of aerosols overnight. This insight offers policymakers targeted geographic regions for emission controls to mitigate urban heat and haze simultaneously.

An analysis of the extreme 2015 peat and forest fires showed that carbon emissions during that episode exceeded those of the previous record year in the late 1990s. Using satellite‐derived fire radiative power together with in situ smoke measurements and chemical transport modelling, the study quantified unprecedented releases of CO₂, CO, CH₄ and aerosol mass from maritime Southeast Asia. Findings underscored the critical role of extended drought in amplifying smouldering peat combustion and its climatic and health consequences.

Work on the 2013 Sumatran fires, occurring in a non-drought year, revealed that even brief dry‐spell events in humid environments can ignite extensive peatland burning. Remote sensing data coupled with hydrological records indicated that such fires, though short‐lived, contributed disproportionately to regional aerosol burdens and greenhouse-gas outputs. This challenged the assumption that severe haze episodes are confined to El Niño years and highlighted the need for continuous land‐management vigilance.

Aerosol Emissions from Biomass Burning in Southeast Asia publication trend

The graph below shows the total number of articles in aerosol emissions from biomass burning in southeast asia across all publications each year (not limited to Nature Index journals).

Technical terms

Aerosol optical depth (AOD): A measure of the extinction of solar radiation by aerosol particles in a vertical column of atmosphere.

PM₂.₅: Particulate matter with aerodynamic diameter smaller than 2.5 micrometres, able to penetrate deep into the respiratory tract.

Peatland: Wetland ecosystems with deep accumulations of organic soil (peat) that, when dried, become highly combustible.

Primary organic aerosol (POA): Particles directly emitted from combustion, consisting of complex organic compounds.

Secondary organic aerosol (SOA): Particulate matter formed in the atmosphere from the oxidation of volatile organic compounds.

Transboundary air pollution (TAP): Airborne pollutants originating in one jurisdiction and transported to another by prevailing winds.

References

1. Land surface temperature and transboundary air pollution: a case of Bangkok Metropolitan Region. Scientific Reports (2024).
2. Fire carbon emissions over maritime southeast Asia in 2015 largest since 1997. Scientific Reports (2016).
3. Major atmospheric emissions from peat fires in Southeast Asia during non-drought years: evidence from the 2013 Sumatran fires. Scientific Reports (2014).
4. Source emission contributions to particulate matter and ozone, and their health impacts in Southeast Asia. Environment International (2024).
5. Deterioration of respiratory health following changes to land cover and climate in Indonesia. One Earth (2023).
6. Fire carbon emissions over Equatorial Asia reduced by shortened dry seasons. npj Climate and Atmospheric Science (2023).