Trace gas emissions from combustion of peat, crop residue, domestic biofuels, grasses, and other fuels: configuration and Fourier transform infrared (FTIR) component of the fourth Fire Lab at Missoula Experiment (FLAME-4)

Abstract

Abstract. During the fourth Fire Lab at Missoula Experiment (FLAME-4, October–November 2012) a large variety of regionally and globally significant biomass fuels was burned at the US Forest Service Fire Sciences Laboratory in Missoula, Montana. The particle emissions were characterized by an extensive suite of instrumentation that measured aerosol chemistry, size distribution, optical properties, and cloud-nucleating properties. The trace gas measurements included high-resolution mass spectrometry, one- and two-dimensional gas chromatography, and open-path Fourier transform infrared (OP-FTIR) spectroscopy. This paper summarizes the overall experimental design for FLAME-4 – including the fuel properties, the nature of the burn simulations, and the instrumentation employed – and then focuses on the OP-FTIR results. The OP-FTIR was used to measure the initial emissions of 20 trace gases: CO2, CO, CH4, C2H2, C2H4, C3H6, HCHO, HCOOH, CH3OH, CH3COOH, glycolaldehyde, furan, H2O, NO, NO2, HONO, NH3, HCN, HCl, and SO2. These species include most of the major trace gases emitted by biomass burning, and for several of these compounds, this is the first time their emissions are reported for important fuel types. The main fire types included African grasses, Asian rice straw, cooking fires (open (three-stone), rocket, and gasifier stoves), Indonesian and extratropical peat, temperate and boreal coniferous canopy fuels, US crop residue, shredded tires, and trash. Comparisons of the OP-FTIR emission factors (EFs) and emission ratios (ERs) to field measurements of biomass burning verify that the large body of FLAME-4 results can be used to enhance the understanding of global biomass burning and its representation in atmospheric chemistry models. Crop residue fires are widespread globally and account for the most burned area in the US, but their emissions were previously poorly characterized. Extensive results are presented for burning rice and wheat straw: two major global crop residues. Burning alfalfa produced the highest average NH3 EF observed in the study (6.63 ± 2.47 g kg−1), while sugar cane fires produced the highest EF for glycolaldehyde (6.92 g kg−1) and other reactive oxygenated organic gases such as HCHO, HCOOH, and CH3COOH. Due to the high sulfur and nitrogen content of tires, they produced the highest average SO2 emissions (26.2 ± 2.2 g kg−1) and high NOx and HONO emissions. High variability was observed for peat fire emissions, but they were consistently characterized by large EFs for NH3 (1.82 ± 0.60 g kg−1) and CH4 (10.8 ± 5.6 g kg−1). The variability observed in peat fire emissions, the fact that only one peat fire had previously been subject to detailed emissions characterization, and the abundant emissions from tropical peatlands all impart high value to our detailed measurements of the emissions from burning three Indonesian peat samples. This study also provides the first EFs for HONO and NO2 for Indonesian peat fires. Open cooking fire emissions of HONO and HCN are reported for the first time, and the first emissions data for HCN, NO, NO2, HONO, glycolaldehyde, furan, and SO2 are reported for "rocket" stoves: a common type of improved cookstove. The HCN / CO emission ratios for cooking fires (1.72 × 10−3 ± 4.08 × 10−4) and peat fires (1.45 × 10−2 ± 5.47 × 10−3) are well below and above the typical values for other types of biomass burning, respectively. This would affect the use of HCN / CO observations for source apportionment in some regions. Biomass burning EFs for HCl are rare and are reported for the first time for burning African savanna grasses. High emissions of HCl were also produced by burning many crop residues and two grasses from coastal ecosystems. HCl could be the main chlorine-containing gas in very fresh smoke, but rapid partitioning to aerosol followed by slower outgassing probably occurs.

Derivation of greenhouse gas emission factors for peatlands managed for extraction in the Republic of Ireland and the United Kingdom

“…Yokelson et al, 1996;Bertschi et al, 2003) and comparable with the reported range of MCE in other studies of high-latitude peats (Yokelson et al, 1997;Stockwell et al, 2014). Emission factors for CO 2 and CO are also typical of smouldering combustion and similar to those from other peat studies, particularly Yokelson et al (1997).…”

“…Järveoja et al, 2012;Mander et al, 2012;Salm et al, 2012;Strack et al, 2014), (c) no data from ROI or UK peatlands were included in the IPCC derivation, which might mean that the Tier 1 value may not be appropriate for these countries, and (d) no distinction is made between industrial or domestic extraction sites, despite large differences in their drainage, vegetation cover and management characteristics. In addition, previous studies of peatland fire EFs have focused on the boreal peatlands of Alaska (Yokelson et al, 1997) and Canada (Stockwell et al, 2014) and the temperate peatlands of Minnesota (Yokelson et al, 1997) and North Carolina (Stockwell et al, 2014). These studies found that the smouldering combustion of peats associated with low combustion efficiency leads to relatively lower CO 2 emissions (compared with other ecosystems) and much higher carbon monoxide (CO), CH 4 , and other non-CH 4 hydrocarbon emissions.…”

“…As much of the peat- Table 3. Mean modified combustion efficiency (MCE) and emission factors (g kg −1 dry fuel burned) reported by this study and those for the same trace gases reported by previous studies of temperate or boreal peat (Yokelson et al 1997;Stockwell et al 2014). The mean and standard deviation of the emission factor is calculated from individual sample burns; nr: not reported.…”

Chemical characterization of fine particulate matter emitted by peat fires in Central Kalimantan, Indonesia, during the 2015 El Niño

“…Many of these studies primarily focused on chemically characterizing gaseous emissions (Benner, 1977;Chen et al, 2007;Christian et al, 2003;Geron and Hays, 2013;May et al, 2014;McMahon et al, 1980;Ward, 1990;Hatch et al, 2015;Stockwell et al, 2015Stockwell et al, , 2014George et al, 2016;Black et al, 2016;Iinuma et al, 2007;Yokelson et al, 1997) while fewer focused on the PM fraction Fujii et al, 2014Fujii et al, , 2015aIinuma et al, 2007). Peatland fire emissions were not considered in the biomass burning emission inventory published by Andreae and Merlet (2001).…”

Chemical characterization of fine particulate matter emitted by peat fires in Central Kalimantan, Indonesia, during the 2015 El Niño

“…Many of these studies primarily focused on chemically characterizing gaseous emissions (Benner, 1977;Chen et al, 2007;Christian et al, 2003;Geron and Hays, 2013;May et al, 2014;McMahon et al, 1980;Ward, 1990;Hatch et al, 2015;Stockwell et al, 2015;Stockwell et al, 2014;George et al, 2016;Black et al, 2016;Iinuma et al, 2007;Yokelson et al, 1997) while fewer focused on the PM fraction Fujii et al, 2014;Fujii et al, 2015a;Iinuma et al, 2007). Peatland fire emissions were not considered in the 5 biomass burning emission inventory published by Andreae and Merlet (2001).…”