Field measurements of trace gases and aerosols emitted by peat fires in Central Kalimantan, Indonesia, during the 2015 El Niño
Year: 2016
Type: article
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, g compound per kg biomass burned) for CO2, CO, CH4, non-methane hydrocarbons up to C10, 15 oxygenated organic compounds, NH3, HCN, NOx, OCS, HCl, etc.; up to ~90 gases in all. 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) 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. 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 (2012) 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 measureable 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 fuel burned) and the single scattering albedo (SSA) at 870 and 405 nm, as well as the absorption Ångstrӧm exponents (AAE). By coupling the absorption and co-located trace gas and filter data we estimated black carbon (BC) EFs (g/kg) and the mass absorption coefficient (MAC, m2/g) 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). 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).
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Climate action
Open Access status: gold
Estimated APC paid: $1,725
Awards: Collaborative Research: Measurements of Selected Combustion Emissions in Nepal and Bhutan Integrated with Source Apportionment and Chemical Transport Modeling for South Asia, PROJECT SUMMARY: BECAUSE OF EPISODIC UNCONTROLLED FIRES WITHIN DRAINED PEAT-SWAMP FORESTS INDONESIA IS RANKED THE 4TH LARGEST CO2EMITTER OVER THE LAST HALF CENTURY. THE FORMER 1 MILLION HECTARE MEGA RICE PROJECT (MRP) DESIGNED TO CONVERT EXTENSIVE PEAT LANDSINTO FARM LANDS IS A MAJOR EMISSIONS SOURCE. DEEP ORGANIC SOILS STORING VAST AMOUNTS OF CARBON ARE NOW BEING LOST TO DECOMPOSITIONAND COMBUSTION. THE 120 000 HA KALIMANTAN FORESTS AND CLIMATE PARTNERSHIP (KFCP) REDUCED EMISSIONS FROM DEFORESTATIONAND FOREST DEGRADATION (REDD+) PROJECT IS WITHIN THE FORMER MRP. IN COLLABORATION WITH THE INDONESIAN GOVERNMENT S FORESTRYRESEARCH AND DEVELOPMENT AGENCY (FORDA) WE WILL DEVELOP A PROTOTYPE PEAT-FIRE EMISSIONS MODULE FOR KFCP TO INCORPORATE INTOTHE INDONESIAN NATIONAL CARBON ACCOUNTING SYSTEM (INCAS). THIS CAPACITY WILL ENABLE ANNUAL QUANTIFICATION OF FIRE-RELATED EMISSIONS.OUR RESEARCH PROJECT WILL UTILIZE LANDSAT AND MODIS DATA AND PRODUCTS TO QUANTIFY LAND COVER CHANGES BURNED AREA AND ESTIMATE THETIMING OF FIRE ACTIVITY. WE WILL INCORPORATE TRMM DATA FOR RELATING PRECIPITATION HISTORY TO THE TIMING OF OBSERVED WATER TABLE CHANGESTHAT IMPACT PEAT-FIRE ACTIVITY AT KFCP. WE WILL INTEGRATE SATELLITE DATA WITH EXISTING AERIAL KFCP LIDAR (2007&2010) AND PROPOSEA REPEAT LIDAR COLLECTION DURING THE STUDY TO PROVIDE QUANTIFIED TEMPORAL TOPOGRAPHIC CHANGE MAPS TO VALIDATE OUR MODELED RESULTSOF FIRE-RELATED PEAT CONSUMPTION. THIS PROJECT WILL LEVERAGE THE EXTENSIVE AND ONGOING DATA COLLECTION EFFORTS FOR HYDROLOGY FUELS LAND USES AND FIRE OCCURRENCE AT KFCP WITH OUR INITIAL FIELD WORK AND LABORATORY TESTING OF REGIONAL PEAT COMBUSTION AND EMISSIONCHARACTERISTICS TO PROVIDE GUIDED FIELD TESTING OF BACKGROUND AND FIRE-RELATED CARBON EMISSION RATES AND TYPES (E.G. METHANE CO2 CO PARTICULATES OTHER) DURING EL NINO AND NON-EL NINO YEARS AS AVAILABLE. THROUGH GROUNDBREAKING EMISSIONS FIELD SAMPLING OFIN-SITU SMOLDERING SURFACE SHALLOW (<20 CM) AND DEEP (>20 CM) PEAT FIRES WITH ON-SITE GAS CHROMATOGRAPHY FOR QUANTIFYING REACTIVESPECIES WHOLE AIR SAMPLING FOR PRECISE LAB MEASUREMENTS OF NON-REACTIVE GASES AND SIMULTANEOUS FILTER SAMPLING OF PARTICULATES WEWILL CREATE COMPREHENSIVE AND PERTINENT EMISSIONS FACTORS (EFS) THAT WILL BE CRITICALLY IMPORTANT FOR ASSESSING THE HEALTH IMPACTS ANDTOTAL GLOBAL WARMING POTENTIAL (GWP) OF THESE EMISSIONS. IN OUR INTERDISCIPLINARY RESEARCH WE WILL INVESTIGATE THE CHAINS OF SOCIALAND BIO-PHYSICAL EVENTS LEADING TO THESE DEEP-PEAT FIRES INTEGRATING FIRE SCENE ANALYSES WITH SOCIAL DATA TO DESCRIBE WHEN WHERE HOW AND UNDER WHAT CONDITIONS FIRES WITHIN KFCP HAVE OCCURRED SO THAT MORE EFFECTIVE MITIGATION STRATEGIES CAN BE DEVELOPED IN THEFUTURE. ACCURATE ACCOUNTING OF PEAT-FIRE CARBON EMISSIONS REQUIRES UNDERSTANDING HOW THEIR PRESENCE DEPTH OF BURNING AND SPREADRATES RELATE TO THE INTERPLAY OF CLIMATE WEATHER LAND USE LAND COVER DRAINAGE STATUS DISTURBANCE HISTORY FIRE TYPE PEAT DEPTH ANDCOMPOSITION. MODELING THIS PHENOMENON REQUIRES DEFINING 1) THE ANNUAL SURFACE AREA BURNED 2) THE AVAILABLE FUEL FRACTION (BURNABLE)AT EACH LOCATION THROUGH TIME AND 3) THE AMOUNT OF FUEL CONSUMED PER UNIT AREA. WE WILL IMPLEMENT A MODELING APPROACH THAT INITIALLYUSES EXISTING DATA ON THE PEAT HYDROLOGY CLIMATE LAND COVER BURNED AREA TIMING OF IGNITIONS AND FUEL LOADS TO STOCHASTICALLY PROVIDEPEAT FIRE PROBABILITY AND PARAMETERIZE DEPTH AND AREA BURNED FROM THE 2007 LIDAR DATA. THIS INITIAL MODEL WILL BE USED TO PROJECT THEEXPECTED AREA TYPE AND DEPTH OF BURNING FROM 2007-2011 AND THEN CHECKED AGAINST THE 2011 LIDAR DATA SET TO REFINE CALIBRATION OF THEMODELED PARAMETERS. THE THIRD MODELING PHASE WILL PROVIDE MONTE CARLO ESTIMATES OF TYPE DEPTH AND AREA OF BURNING WITH EMISSIONSQUANTITATIVELY WEIGHTED BY APPROPRIATE EFS DERIVED FOR SURFACE SHALLOW AND DEEP PEAT SMOKE AMOUNTS THAT WILL BE VALIDATED USING THEPROPOSED THIRD LIDAR DA, BIOMASS BURNING IS THE LARGEST GLOBAL SOURCE OF PRIMARY FINE ORGANIC AEROSOL (~50 TG/YR) AND THE SECOND LARGEST SOURCE OF REACTIVE NON-METHANE ORGANI
OpenAlex ID: W2423882823