Characterization of biomass burning emissions from cooking fires, peat, crop residue, and other fuels with high-resolution proton-transfer-reaction time-of-flight mass spectrometry

摘要

We deployed a high-resolution proton-transfer-reaction time-of-flight massspectrometer (PTR-TOF-MS) to measure biomass-burning emissions from peat,crop residue, cooking fires, and many other fire types during the fourthFire Lab at Missoula Experiment (FLAME-4) laboratory campaign. A combinationof gas standard calibrations and composition sensitive, mass-dependentcalibration curves was applied to quantify gas-phase non-methane organiccompounds (NMOCs) observed in the complex mixture of fire emissions. We usedseveral approaches to assign the best identities to most major "exact masses",including many high molecular mass species. Using these methods,approximately 80–96% of the total NMOC mass detected by the PTR-TOF-MS andFourier transform infrared (FTIR) spectroscopy was positively or tentativelyidentified for major fuel types. We report data for many rarely measured orpreviously unmeasured emissions in several compound classes includingaromatic hydrocarbons, phenolic compounds, and furans; many of these aresuspected secondary organic aerosol precursors. A large set of new emissionfactors (EFs) for a range of globally significant biomass fuels ispresented. Measurements show that oxygenated NMOCs accounted for the largestfraction of emissions of all compound classes. In a brief study of varioustraditional and advanced cooking methods, the EFs for these emissions groupswere greatest for open three-stone cooking in comparison to their more advancedcounterparts. Several little-studied nitrogen-containing organic compoundswere detected from many fuel types, that together accounted for 0.1–8.7%of the fuel nitrogen, and some may play a role in new particle formation.