Measurements of I/SVOCs in biomass-burning smoke using solid-phase extraction disks and two-dimensional gas chromatography

Abstract

Abstract. Biomass-burning organic-aerosol (OA) emissions are known to exhibit semi-volatile behavior that impacts OA loading during plume transport. Because such semi-volatile behavior depends in part on OA composition, improved speciation of intermediate and semi-volatile organic compounds (I/SVOCs) emitted during fires is needed to assess the competing effects of primary OA volatilization and secondary OA production. In this study, 18 laboratory fires were sampled in which a range of fuel types were burned. Emitted I/SVOCs were collected onto Teflon filters and solid-phase extraction (SPE) disks to qualitatively characterize particulate and gaseous I/SVOCs, respectively. Derivatized filter extracts were analyzed using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC × GC-TOFMS). Quality control tests were performed using biomass-burning relevant standards and demonstrate the utility of SPE disks for untargeted analysis of air samples. The observed chromatographic profiles of I/SVOCs in coniferous fuel-derived smoke samples were well correlated with each other, but poorly correlated with other fuel types (e.g., herbaceous and chaparral fuels). Emissions of benzenediol isomers were also shown to be fuel dependent. The combined Teflon and SPE filter data captured differences in gas-particle partitioning of the benzenediol isomers, with hydroquinone having a significantly higher particle-phase fraction than catechol due to its lower volatility. Additionally, the speciated volatility distribution of I/SVOCs in smoke from a rotten-log fire was estimated to evaluate the composition of potentially volatilized primary OA, which was entirely attributed to oxygenated (or other heteroatomic) compounds. The isomer-dependent partitioning and the speciated volatility distributions both suggest the need for better understanding of gas-phase and heterogenous reaction pathways of biomass-burning-derived I/SVOCs in order to represent the atmospheric chemistry of smoke in models.

Chemical Composition of PM<sub>2.5</sub> in October 2017 Northern California Wildfire Plumes

“…In the two samples, the volatility distribution and the distribution were almost identical. The volatility distribution obtained is similar to particle-phase primary BBOA reported by Hatch et al (2018) in the way that most compounds reside in 10 0 < C* < 10 2 µg m -3 bins. But the standard deviation of log10C* in our study is higher than that in Hatch et al (2018), which could be related to fuel differences and aging.…”

“…The volatility distribution obtained is similar to particle-phase primary BBOA reported by Hatch et al (2018) in the way that most compounds reside in 10 0 < C* < 10 2 µg m -3 bins. But the standard deviation of log10C* in our study is higher than that in Hatch et al (2018), which could be related to fuel differences and aging. Compounds in the 10 -2 µg m -3 < C* < 10 -1 µg m -3 bin were mainly aliphatics and tri-terpenoids, while 1 µg m -3 to 10 2 µg m -3 bins consist of sugars, aromatic compounds, and other oxygenated compounds.…”

“…They were enriched in the plumes on Oct 10 and 17, as well as the plumes on Oct 11-13, which further confirms the ubiquity of hardwood fuels in all the fires affecting Berkeley. Hydroquinone and two other compounds were also shown to be good tracers for manzanita fires (Jen et al, 2018). They were present in most of the plumes, which is in line with the prevalence of manzanita in that region.…”

Atmospheric Evolution of Emissions from a Boreal Forest Fire: The Formation of Highly-Functionalized Oxygen-, Nitrogen-, and Sulfur-Containing Compounds

“…Forest fires are predicted to become increasingly prevalent and severe with climate change (Abatzoglou and Williams, 2016;Barbero et al, 2015;Jolly et al, 2015). These fires are an important and uncontrolled source of gas-and particle-phase compounds to the atmosphere, including a complex mixture of gas-phase reactive organic carbon, primary organic aerosol (POA), carbon monoxide, carbon dioxide, methane, ammonia, nitrogen oxides, and black carbon (Akagi et al, 2011;Gilman et al, 2015;Hatch et al, 2015Hatch et al, , 2018Koss et al, 2018;Vicente et al, 2013;Yokelson et al, 2013). Many of these emitted compounds are precursors to downwind ozone and secondary organic aerosol (SOA) production (Ahern et al, 2019;Buysse et al, 2019;Gilman et al, 2015;Hennigan et al, 2011;Lim et al, 2019).…”

“…These health and climate effects are sensitive to the elemental and structural composition of gas-and particle-phase emissions and transformation products (Ditto et al, 2019;Hallquist et al, 2009;Nozière et al, 2015). As a result, past studies have used online and offline mass spectrometry techniques to characterize the chemical composition of fresh and aged biomass burning smoke and have revealed a wide array of emitted hydrocarbons and oxygen-, nitrogen-, or sulfur-containing functionalized species (Ahern et al, 2019;Bertrand et al, 2018;Gilman et al, 2015;Hatch et al, 2015Hatch et al, , 2018Hatch et al, , 2019Iinuma et al, 2010;Koss et al, 2018;Laskin et al, 2009;Yokelson et al, 2013). However, the emissions and chemical transformations occurring in ambient biomass burning plumes are extremely complex and despite previous measurements remain poorly understood at the molecular-level.…”