Review of emissions from smouldering peat fires and their contribution to regional haze episodes

Abstract

Abstract. Smouldering peat fires, the largest fires on Earth in terms of fuel consumption, are reported in six continents and are responsible for regional haze episodes. Haze is the large-scale accumulation of smoke at low altitudes in the atmosphere. It decreases air quality, disrupts transportation and causes health emergencies. Research on peat emissions and haze is modest at best and many key aspects remain poorly understood. Here, we compile an up-to-date inter-study of peat fire emission factors (EFs) found in the literature both from laboratory and from field studies. Tropical peat fires yield larger EFs for the prominent organic compounds than boreal and temperate peat fires, possibly due to the higher fuel carbon content (56.0 vs 44.2%). In contrast, tropical peat fires present slightly lower EFs for particulate matter with diameter #2.5 mm (PM 2.5 ) for unknown reasons but are probably related to combustion dynamics. An analysis of the modified combustion efficiency, a parameter widely used for determining the combustion regime of wildfires, shows it is partially misunderstood and highly sensitive to unknown field variables. This is the first review of the literature on smouldering peat emissions. Our integration of the existing literature allows the identification of existing gaps in knowledge and is expected to accelerate progress towards mitigation strategies.

Investigating Smoke Aerosol Emission Coefficients Using MODIS Active Fire and Aerosol Products: A Case Study in the CONUS and Indonesia

“…The peatland C e (52.432 g/MJ) is obviously higher than that of forests (21.733 g/MJ in the CONUS and 29.996 g/MJ in Indonesia). This higher peatland C e has been shown in findings from previous literature (Hu et al, 2018;Kaiser et al, 2012). First, C e is a product of a combustion factor and an emission factor (Seiler & Crutzen, 1980;Wooster et al, 2005):…”

“…Therefore, a fire with a given FRE can emit greater TPM while smoldering than that if it was flaming. Relative to flaming fires, smoldering fires release larger amounts of organic carbon (Hu et al, ) that account for 50%–60% of total emissions (Reid, Koppmann, et al, ).…”

Wildland fire emission factors in North America: synthesis of existing data, measurement needs and management applications

“…flaming v. smouldering and prescribed underburn v. crown fire). Because many smoke management issues associated with wildland fire emissions are from residual long-term smouldering sources, characterising the fuels and EFs associated with these burning conditions is critical for fire management applications (Urbanski 2013;Yokelson et al 2013;Hu et al 2018;Peterson et al 2018). Some studies also suggest that factors driving burning conditions including wind, fuel moisture and fire behaviour may more strongly influence pollutant emissions than differences in fuel type or region (Yokelson et al 2013;Koss et al 2018).…”

Impact of the June 2018 Saddleworth Moor wildfires on air quality in northern England

“…As peat is a substantially oxygenated fuel source, it can burn underground for long periods (e.g. weeks to months (Hu et al 2018, Roulston et al 2018) making peat fires extremely difficult to control. Emissions from peat are poorly understood but it is thought that during the flaming stage, fires emit large amounts of soot and nitrogen oxides (NO x ), while in the smouldering stage they emit much more carbon monoxide (CO), methane (CH 4 ), volatile organic compounds (VOCs) and particulate matter (PM) (Turetsky et al 2015).…”