Comprehensive Laboratory Measurements of Biomass-Burning Emissions: 1. Emissions from Indonesian, African, and Other Fuels

[1] Trace gas and particle emissions were measured from 47 laboratory fires burning 16 regionally to globally significant fuel types. Instrumentation included the following: open-path Fourier transform infrared spectroscopy; proton transfer reaction mass spectrometry; filter sampling with subsequent analysis of particles with diameter \u3c2.5 μm for organic and elemental carbon and other elements; and canister sampling with subsequent analysis by gas chromatography (GC)/flame ionization detector, GC/electron capture detector, and GC/mass spectrometry. The emissions of 26 compounds are reported by fuel type. The results include the first detailed measurements of the emissions from Indonesian fuels. Carbon dioxide, CO, CH4, NH3, HCN, methanol, and acetic acid were the seven most abundant emissions (in order) from burning Indonesian peat. Acetol (hydroxyacetone) was a major, previously unobserved emission from burning rice straw (21–34 g/kg). The emission factors for our simulated African fires are consistent with field data for African fires for compounds measured in both the laboratory and the field. However, the higher concentrations and more extensive instrumentation in this work allowed quantification of at least 10 species not previously quantified for African field fires (in order of abundance): acetaldehyde, phenol, acetol, glycolaldehyde, methylvinylether, furan, acetone, acetonitrile, propenenitrile, and propanenitrile. Most of these new compounds are oxygenated organic compounds, which further reinforces the importance of these reactive compounds as initial emissions from global biomass burning. A few high-combustion-efficiency fires emitted very high levels of elemental (black) carbon, suggesting that biomass burning may produce more elemental carbon than previously estimated

Field measurements of trace gases and aerosols emitted by peat fires in Central Kalimantan, Indonesia, during the 2015 El Nino

Abstract. Peat fires in Southeast Asia have become a major annual source of trace gases and particles to the regional–global atmosphere. The assessment of their influence on atmospheric chemistry, climate, air quality, and health has been uncertain partly due to a lack of field measurements of the smoke characteristics. During the strong 2015 El Niño event we deployed a mobile smoke sampling team in the Indonesian province of Central Kalimantan on the island of Borneo and made the first, or rare, field measurements of trace gases, aerosol optical properties, and aerosol mass emissions for authentic peat fires burning at various depths in different peat types. This paper reports the trace gas and aerosol measurements obtained by Fourier transform infrared spectroscopy, whole air sampling, photoacoustic extinctiometers (405 and 870 nm), and a small subset of the data from analyses of particulate filters. The trace gas measurements provide emission factors (EFs; grams of a compound per kilogram biomass burned) for up to  ∼  90 gases, including CO2, CO, CH4, non-methane hydrocarbons up to C10, 15 oxygenated organic compounds, NH3, HCN, NOx, OCS, HCl, etc. The modified combustion efficiency (MCE) of the smoke sources ranged from 0.693 to 0.835 with an average of 0.772 ± 0.053 (n  =  35), indicating essentially pure smoldering combustion, and the emissions were not initially strongly lofted. The major trace gas emissions by mass (EF as g kg−1) were carbon dioxide (1564 ± 77), carbon monoxide (291 ± 49), methane (9.51 ± 4.74), hydrogen cyanide (5.75 ± 1.60), acetic acid (3.89 ± 1.65), ammonia (2.86 ± 1.00), methanol (2.14 ± 1.22), ethane (1.52 ± 0.66), dihydrogen (1.22 ± 1.01), propylene (1.07 ± 0.53), propane (0.989 ± 0.644), ethylene (0.961 ± 0.528), benzene (0.954 ± 0.394), formaldehyde (0.867 ± 0.479), hydroxyacetone (0.860 ± 0.433), furan (0.772 ± 0.035), acetaldehyde (0.697 ± 0.460), and acetone (0.691 ± 0.356). These field data support significant revision of the EFs for CO2 (−8 %), CH4 (−55 %), NH3 (−86 %), CO (+39 %), and other gases compared with widely used recommendations for tropical peat fires based on a lab study of a single sample published in 2003. BTEX compounds (benzene, toluene, ethylbenzene, xylenes) are important air toxics and aerosol precursors and were emitted in total at 1.5 ± 0.6 g kg−1. Formaldehyde is probably the air toxic gas most likely to cause local exposures that exceed recommended levels. The field results from Kalimantan were in reasonable agreement with recent lab measurements of smoldering Kalimantan peat for “overlap species,” lending importance to the lab finding that burning peat produces large emissions of acetamide, acrolein, methylglyoxal, etc., which were not measurable in the field with the deployed equipment and implying value in continued similar efforts. The aerosol optical data measured include EFs for the scattering and absorption coefficients (EF Bscat and EF Babs, m2 kg−1 fuel burned) and the single scattering albedo (SSA) at 870 and 405 nm, as well as the absorption Ångström exponents (AAE). By coupling the absorption and co-located trace gas and filter data we estimated black carbon (BC) EFs (g kg−1) and the mass absorption coefficient (MAC, m2 g−1) for the bulk organic carbon (OC) due to brown carbon (BrC). Consistent with the minimal flaming, the emissions of BC were negligible (0.0055 ± 0.0016 g kg−1). Aerosol absorption at 405 nm was  ∼  52 times larger than at 870 nm and BrC contributed  ∼  96 % of the absorption at 405 nm. Average AAE was 4.97 ± 0.65 (range, 4.29–6.23). The average SSA at 405 nm (0.974 ± 0.016) was marginally lower than the average SSA at 870 nm (0.998 ± 0.001). These data facilitate modeling climate-relevant aerosol optical properties across much of the UV/visible spectrum and the high AAE and lower SSA at 405 nm demonstrate the dominance of absorption by the organic aerosol. Comparing the Babs at 405 nm to the simultaneously measured OC mass on filters suggests a low MAC ( ∼  0.1) for the bulk OC, as expected for the low BC/OC ratio in the aerosol. The importance of pyrolysis (at lower MCE), as opposed to glowing (at higher MCE), in producing BrC is seen in the increase of AAE with lower MCE (r2 =  0.65)

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

Fine particulate matter (PM2:5) was collected in situ from peat smoke during the 2015 El Niño peat fire episode in Central Kalimantan, Indonesia. Twenty-one PM samples were collected from 18 peat fire plumes that were primarily smoldering with modified combustion efficiency (MCE) values of 0.725-0.833. PM emissions were determined and chemically characterized for elemental carbon (EC), organic carbon (OC), water-soluble OC, water-soluble ions, metals, and organic species. Fuel-based PM2:5 mass emission factors (EFs) ranged from 6.0 to 29.6 g kg1 with an average of 17:36:0 g kg1. EC was detected only in 15 plumes and comprised 1% of PM mass. Together, OC (72 %), EC (1 %), water-soluble ions (1 %), and metal oxides (0.1 %) comprised 7411% of gravimetrically measured PM mass. Assuming that the remaining mass is due to elements that form organic matter (OM; i.e., elements O, H, N) an OM-to-OC conversion factor of 1.26 was estimated by linear regression. Overall, chemical speciation revealed the following characteristics of peat-burning emissions: high OC mass fractions (72%), primarily water-insoluble OC (8411 %C), low EC mass fractions (1 %), vanillic to syringic acid ratios of 1.9, and relatively high n-alkane contributions to OC (6.2 %C) with a carbon preference index of 1.2-1.6. Comparison to laboratory studies of peat combustion revealed similarities in the relative composition of PM but greater differences in the absolute EF values. The EFs developed herein, combined with estimates of the mass of peat burned, are used to estimate that 3.2-11 Tg of PM2:5 was emitted to atmosphere during the 2015 El Niño peatland fire event in Indonesia. Combined with gas-phase measurements of CO2, CO, CH4, and volatile organic carbon from Stockwell et al. (2016), it is determined that OC and EC accounted for 2.1 and 0.04% of total carbon emissions, respectively. These in situ EFs can be used to improve the accuracy of the representation of Indonesian peat burning in emission inventories and receptor-based models

Assessing Conformity of Scientific Voices and Local Needs to Combat Forest Fire in Indonesia

This study evaluates the compatibility of scientific voices with the needs to combat forest fire as perceived by relevant stakeholders through a review of scholarly output, an evaluation of the conformity between scientists and stakeholder views on forest fire issues, and an analysis of how different types of scientists and voice channels contribute the local needs to combat forest fire in Indonesia. This research indicates that although forest fire has cross-country border impacts, forest fire discourses were dominated by home country issues rather than the concerns of global forest fire events. Further, although information about forest fire is widely available in the scientific journals, the “knowledge utilization” of this information remains low. To improve “knowledge utilization”, scientists can use different channels to disseminate information, in addition to scientific journals. While socialeconomic aspects are perceived to be the prime problem of forest fire in Indonesia, the minimal presentation of social scientists within forest fire discourse is a concern. To address these primary concerns within and outside scientific journals, the involvement of social scientists within the forest fire discourse is very important

Persamaan Alometrik dan Cadangan Karbon Vegetasi pada Hutan Gambut Primer dan Bekas Terbakar

Biosekuestrasi atau penyerapan karbondioksida oleh vegetasi merupakan salah satu pengelolaan cadangan karbon yang penting untuk digarisbawahi dalam setiap pertemuan Internasional, tetapi ketersediaan data tersebut masih kurang lengkap dan tersebar. Data cadangan karbon dari vegetasi dan tanah gambut sangat penting untuk mengurangi variasi pendugaan stok karbon di hutan gambut. Tujuan penelitian ini adalah untuk memformulasikan persamaan alometrik dalam pendugaan biomassa pohon di hutan gambut primer dan bekas kebakaran serta untuk menganalisis cadangan karbon vegetasi di hutan gambut primer dan bekas kebakaran. Penelitian dilakukan di hutan gambut primer (HGP), hutan gambut bekas terbakar berulang tiap tahun (HG1), hutan gambut bekas terbakar setelah tiga tahun (HG3), dan hutan gambut bekas terbakar setelah delapan tahun (HG8). Klaster plot dibuat di setiap hutan gambut primer dan bekas kebakaran yang mewakili periode kondisi setelah kebakaran dan hutan gambut tidak terganggu. Setiap klaster terdiri dari empat subplot lingkaran (jari-jari 7,32 m) dan empat annular lingkaran (jari-jari 17,95 m). Jumlah total adalah 16 subplot lingkaran serta 16 annular lingkaran. Data cadangan biomassa karbon dikumpulkan dalam plot-plot tersebut. Hasil penelitian menunjukkan bahwa untuk menduga biomassa total pada keseluruhan klaster, maka persamaan alometrik yang paling tepat adalah Y = 0,061 (DBHxρxT)1,464. Persamaan alometrik umum keseluruhan klaster tersebut digunakan untuk pengguna di lapangan dalam menghitung cadangan biomassa karbon tegakan. Persamaan umum ini dapat digunakan karena semua klaster penelitian memiliki wilayah zona iklim curah hujan sebesar 2.621-3.339 mm/tahun yang termasuk dalam zona iklim moist 1.500-4.000 mm/tahun (Brown et al., 1989). Masing-masing persamaan alometrik tiap klaster yang diperoleh dari hasil penelitian ini digunakan untuk menduga cadangan biomassa karbon tegakan tiap klaster. Persamaan alometrik terpilih penduga biomassa total untuk hutan gambut primer adalah Y = 0,040 (DBHxρxT)1,524; untuk hutan gambut bekas terbakar berulang tiap tahun adalah Y = 0,098 (DBH)2,350; untuk hutan gambut bekas terbakar setelah tiga tahun adalah Y = 0,084 (DBHxρxT)1,376; untuk hutan gambut bekas terbakar setelah delapan tahun adalah Y = 0,024 (DBHxρxT)1,667. Cadangan karbon total yang merupakan jumlah dari tumbuhan bawah, semai, pancang, tiang, dan pohon adalah sebesar 73,08 tonC/ha di HGP; 4,93 tonC/ha di HG1; 13,64 tonC/ha di HG3; dan 26,13 tonC/ha di HG8

Aplikasi Lubang Resapan Biopori dan Cross Drain untuk Rehabilitasi di Jalan Sarad

Problem yang dihadapi di jalan sarad dalam pemanenan kayu adalah pemadatan tanah, erosi yang tinggi, menurunnya kesuburan tanah, miskinnya cendawan mikoriza dan kurangnya anakan. Untuk meningkatkan produktivitas hutan di jalan sarad, maka diperlukan upaya pemulihan antara lain dengan penanaman pengayaan intensif dan cara lain yang dapat untuk mengurangi laju erosi, meningkatkan kesuburan tanah di jalan sarad dengan menerapkan lubang resapan biopori (LRB) dan cross drain (Cd). Tujuan penelitian ini adalah untuk mendapatkan informasi tentang pemanfaatan LRB dan Cd dalam penanaman pengayaan intensif untuk peningkatan produktifitas jalan sarad di hutan alam bekas tebangan. Lokasi penelitian diberi ijin usaha pemanfaatan hasil hutan kayu hutan alam (IUPHHK-HA) pada hutan produksi Kalimantan Barat selama satu tahun. Rancangan penelitian adalah rancangan acak kelompok pola faktorial 2 x 2 dengan ulangan tiga kali. Faktor pertama yaitu LRB dan faktor kedua yaitu cross drain. Hasil penelitian menunjukkan bahwa interaksi perlakuan LRB dan cross drain memberi pengaruh yang nyata bagi pertumbuhan tinggi tanaman umur satu tahun Shorea leprosula dan Shorea parvifolia sedangkan untuk pertumbuhan diameternya tidak berpengaruh nyata. Perlakuan cross drain dapat meningkatkan serapan hara P, K, C organik di S. leprosula dan hanya serapan P dan C-organik di S. parvifolia

A Field Study of Tropical Peat Fire Behaviour and Associated Carbon Emissions

Tropical peatlands store vast volumes of carbon belowground. Human land uses have led to their degradation, reducing their carbon storage services. Clearing and drainage make peatlands susceptible to surface and belowground fires. Satellites do not readily detect smouldering peat fires, which release globally significant quantities of aerosols and climate-influencing gases. Despite national and international desire to improve management of these fires, few published results exist for in situ tropical peat fire behaviour and associated carbon emissions. We present new field methodology for calculating rates of fire spread within degraded peat (average spread rates, vertical 0.8 cm h−1, horizontal 2.7 cm h−1) and associated peat volume losses (102 m3 ha−1 in August, 754 m3 ha−1 in September) measured at six peat fire sites in Kalimantan, Indonesia, in 2015. Utilizing locally collected bulk density and emission factors, total August and September gas emissions of 27.2 t ha−1 (8.1 tC ha−1) and 200.7 t ha−1 (60.2 tC ha−1) were estimated. We provide much needed, but currently lacking, IPCC Tier 3-level data to improve GHG estimates from tropical peat fires. We demonstrate how calculations of total emission estimates can vary greatly in magnitude (+798% to −26%) depending on environmental conditions, season, peat burn depth methodology, bulk density and emission factors data sources, and assumed versus observed combustion factors. This illustrates the importance of in situ measurements and the need for more refined methods to improve accuracies of GHG estimates from tropical peat fires