Organic tracers of fine aerosol particles in central Alaska: summertime composition and sources

Abstract

Abstract. PM2.5 aerosols were collected at Fairbanks (64.51∘ N and 147.51∘ W) in central Alaska during the summer of 2009 and analyzed for organic tracer compounds using a gas chromatograph–mass spectrometer. The organic compounds were grouped into 14 classes based on their functional groups and sources. Concentrations of the total organics measured ranged from 113 to 1664 ng m−3 (avg 535 ng m−3). Anhydrosugars (avg 186 ng m−3) and n-alkanoic acids (avg 185 ng m−3) were 2 major classes among the 14 compound classes. The similar temporal trends and strong positive correlations among anhydrosugars and n-alkanoic acids demonstrated that biomass burning (BB) is the major source of organic aerosols (OAs) in central Alaska. The dominance of higher molecular weight n-alkanoic acids over lower molecular weight homologs and their carbon preference index (5.6–9.8) confirmed that they were mostly emitted from plant waxes during BB in central Alaska. The mass concentration ratios of levoglucosan to mannosan denoted that softwood is the main biomass burned. The rainfall event distinctly enhanced the levels of mannitol and arabitol due to the growth of fungi and active discharge of fungal spores in the subarctic region. Molecular compositions of biogenic secondary organic aerosol (BSOA) tracers inferred that isoprene is a crucial precursor of BSOA over central Alaska. Our results suggest forest fires and plant emissions to be the crucial factors controlling the levels and molecular composition of OAs in central Alaska. We propose that PM2.5 laden with OAs derived in central Alaska may significantly impact the air quality and climate in the Arctic via long-range atmospheric transport.

An optimized tracer-based approach for estimating organic carbon emissions from biomass burning in Ulaanbaatar, Mongolia

“…3a, rather than ambient temperature. The average K + concentration (0.08 ± 0.05 µg m −3 ) in this study is significantly lower than the K (0.32 µg m −3 ) observed in Ulaanbaatar during -2008(Davy et al, 2011.…”

“…An understanding of the sources of PM is highly relevant for air-quality remediation. Biomass burning (BB) is a major source of organic carbon (OC) in PM 2.5 (PM with aerodynamic diameter ≤ 2.5 µm), and it may become more significant in the future as air-quality regulations restrict other anthropogenic emissions (Davy et al, 2011;Allan et al, 2014;Sullivan et al, 2019). Coal combustion, thermal power plants, and traffic emissions also make potential contributions to the OC content of PM (Watson et al, 2001a, b;Pei et al, 2016;Deshmukh et al, 2019;, modifying PM characteristics such as hygroscopicity, light-attenuating properties, and health impacts (Jung et al, 2009;Sullivan et al, 2019).…”

“…But there are very few estimates of OC emitted from biomass burning (OC BB ) in Ulaanbaatar. Few studies have investigated the chemical characteristics of aerosol in Ulaanbaatar (Jung et al, 2010;Davy et al, 2011;Batmunkh et al, 2013), with none examining the contribution of OC BB and the type of biomass. Therefore, this study estimated the appropriate Table 1.…”

Summertime High Abundances of Succinic, Citric, and Glyoxylic Acids in Antarctic Aerosols: Implications to Secondary Organic Aerosol Formation

“…The mean value of citric acid in the Antarctic is several times higher than those of continental urban aerosols reported for east-coast aerosols (mean: 0.74 and 0.92 ng m −3 during winter and summer, respectively) over tropical India (Fu et al, 2010), summertime mountain aerosols (4.0 and 3.06 ng m −3 in day and nighttime) over Mt. Tai , marine OAs (0.03-7.8 ng m −3 ) collected during a round the world cruise (Fu et al, 2013), and Alaskan aerosols (<1 ng m −3 ; Deshmukh et al, 2019). All these comparison studies suggest that OAs over the Antarctic are highly oxidized and majorly formed through the secondary oxidations of organic precursors that may be enriched in sea-surface micro-layer.…”

Measurement report: Diurnal and temporal variations of sugar compounds in suburban aerosols from the northern vicinity of Beijing, China – an influence of biogenic and anthropogenic sources

“…Fossil fuel combustion and BB emit WSOC and OC. They are also secondarily produced by photochemical oxidation of volatile organic compounds in the atmosphere (Wang et al, 2005;Deshmukh et al, 2019b). Coal combustion and vehicle exhaust can contribute to the high levels of OC and WSOC in aerosols (Xu et al, 2020).…”