Air quality and health impacts of vegetation and peat fires in Equatorial Asia during 2004–2015

Laura Kiely,Md Firoz Khan,Hari A Adrianto,Lailan Syaufina,Christoph Knote,Stephen R Arnold,Carly L Reddington,Christine Wiedinmyer,Luke Conibear,Mohd Talib Latif,Dominick V Spracklen

doi:10.1088/1748-9326/ab9a6c

Abstract

Particulate matter (PM) emissions from vegetation and peat fires in Equatorial Asia cause poor regional air quality. Burning is greatest during drought years, resulting in strong inter-annual variability in emissions. We make the first consistent estimate of the emissions, air quality and public health impacts of Equatorial Asian fires during 2004–2015. The largest dry season (August—October) emissions occurred in 2015, with PM emissions estimated as 9.4 Tg, more than triple the average dry season emission (2.7 Tg). Fires in Sumatra and Kalimantan caused 94% of PM emissions from fires in Equatorial Asia. Peat combustion in Indonesian peatlands contributed 45% of PM emissions, with a greater contribution of 68% in 2015. We used the WRF-chem model to simulate dry season PM for the 6 biggest fire years during this period (2004, 2006, 2009, 2012, 2014, 2015). The model reproduces PM concentrations from a measurement network across Malaysia and Indonesia, suggesting our PM emissions are realistic. We estimate long-term exposure to PM resulted in 44 040 excess deaths in 2015, with more than 15 000 excess deaths annually in 2004, 2006, and 2009. Exposure to PM from dry season fires resulted in an estimated 131 700 excess deaths during 2004–2015. Our work highlights that Indonesian vegetation and peat fires frequently cause adverse impacts to public health across the region.

Highlights

Vegetation and peat fires in Equatorial Asia contribute to climate change (Page et al 2002, Tosca et al 2013) and poor regional air quality (Field et al 2009, Reddington et al 2014, Lee et al 2017)
The average emissions of CO and CO2 are similar (FB = −0.04 and fractional bias (FB) = 0.07) for the two inventories, while FINNpeatSM has greater dry season PM2.5 emissions (FB = 0.48), due to higher PM2.5 emission factors (EF) for peat combustion applied in FINNpeatSM (22.3 g kg−1) compared to GFED4s (9.1 g kg−1)
We combined a new method of calculating emissions from peat fires (FINNpeatSM), a regional air quality model and a concentration-response function to make the first consistent estimate of the impacts of smoke from Equatorial Asian fires on human health over the period 2004 to 2015

Summary

Introduction

Vegetation and peat fires in Equatorial Asia contribute to climate change (Page et al 2002, Tosca et al 2013) and poor regional air quality (Field et al 2009, Reddington et al 2014, Lee et al 2017). Fires are influenced by climate, land-use and land management (van der Werf et al 2008, Page and Hooijer 2016), and air quality degradation is greatest in dry years when the most extensive fires occur (Marlier et al 2012, Koplitz et al 2016, Crippa et al 2016). Peat fires have higher emission factors for many atmospheric pollutants than vegetation fires (Hu et al 2018, Kiely et al 2019) Together these factors result in peat fires contributing 71%–86% of fire emissions in Equatorial Asia (Heil et al 2007, Kiely et al 2019)

Methods

Results

Conclusion