Sensitivity of population smoke exposure to fire locations in Equatorial Asia

Abstract

Land clearing by fire in Equatorial Asia, a substantial fraction for conversion to oil palm plantations, can lead to high smoke concentrations across this densely populated region and represents a serious public health concern. Here we use the adjoint of the GEOS-Chem chemical transport model to show that population exposure to the smoke is highly dependent on where the fires from clearing (and other activities) take place. In 2006, we find that Sumatran fires disproportionately contributed to the regional population-weighted smoke exposure (37% of regional fire emissions, 63% of the exposure). The information from the adjoint can provide guidance for targeted land conservation as oil palm agriculture expands. Protecting peatswamp forests in Southeast Sumatra emerges as a high priority. We present the adjoint as a tool that can be useful in a cost-benefit analysis to inform policymakers on the relative merits of targeting conservation in different regions of Equatorial Asia.