Seasonal variations of stable carbon isotopic composition and biogenic tracer compounds of water-soluble organic aerosols in a deciduous forest

Abstract

<jats:p>Abstract. To investigate the seasonal changes in biogenic water-soluble organic carbon (WSOC) aerosols in a boreal forest, aerosol samples were collected continuously in the canopy of a deciduous forest in northern Japan during 2009–2010. Stable carbon isotopic composition of WSOC (δ13CWSOC) in total suspended particulate matter (TSP) exhibited a distinct seasonal cycle, with lower values from June through September (−25.5±0.5 ‰). This cycle follows the net CO2 exchange between the forest ecosystem and the atmosphere, indicating that δ13CWSOC likely reflects the biological activity at the forest site. WSOC concentrations showed the highest values in early summer and autumn. Positive matrix factorization (PMF) analysis indicated that the factor in which biogenic secondary organic aerosols (BSOAs) dominated accounted for ~40 % of the highest concentrations of WSOC, where BSOAs mostly consisted of α-/β-pinene SOA. In addition, primary biological aerosol particles (PBAPs) made similar contributions (~57 %) to the WSOC near the forest floor in early summer. This finding indicates that the production of both primary and secondary WSOC aerosols is important during the growing season in a deciduous forest. The methanesulfonic acid (MSA) maximum was also found in early summer and had a distinct vertical gradient with larger concentrations near the forest floor. Together with the similar vertical gradients found for WSOC and δ13CWSOC as well as the α-/β-pinene SOA tracers, our results indicate that the forest floor, including ground vegetation and soil, acts as a significant source of WSOC in TSP within a forest canopy at the study site.</jats:p>

Time-resolved variations in the distributions of inorganic ions, carbonaceous components, dicarboxylic acids and related compounds in atmospheric aerosols from Sapporo, northern Japan during summertime

“…It is well established that K + and NO 3 -are mostly derived from biomass burning (Andreae, 1983) and anthropogenic emissions, respectively. WSOC is more enriched in atmospheric aerosols influenced by higher plant and biomass burning emissions (Kiss et al, 2002;Miyazaki et al, 2012) whereas WIOC is more enriched in aerosols influenced by anthropogenic (Favez et al, 2008) and marine (Facchini et al, 2008) emissions. As shown in Fig.…”

Contribution of dissolved organic matter to submicron water-soluble organic aerosols in the marine boundary layer over the eastern equatorial Pacific

“…A cascade impactor (CI; Series 230, Tisch Environmental, Cleves, OH, USA) attached to a high-volume air sampler (HVAS; Model 120SL, Kimoto Electric, Osaka, Japan) was used to collect submicron particles (Miyazaki et al, 2012). The sampler was located on the upper deck of the ship.…”

“…In addition, the concentrations of total carbon (TC) and the δ 13 C of TC (δ 13 C TC ) (i.e., without water extraction) were also measured with the EA-IRMS for the same aerosol samples (Miyazaki et al, 2010). Further details of the analytical method used for isotopic analysis are given by Miyazaki et al (2012).…”

“…The -COOH and -OH functional groups in the extracts were reacted with N,O-bis-(trimethylsilyl)trifluoroacetamide (BSTFA) to derive trimethylsilyl (TMS) esters and TMS ethers, respectively. The TMS derivatives were then analyzed for α-glucose, β-glucose, α-fructose, β-fructose, and a homologous series of straight-chain fatty acids (C 12 -C 19 saturated acids) using a capillary gas chromatograph (GC7890, Agilent, Santa Clara, CA, USA) coupled to a mass spectrometer (5973 MSD, Agilent, Santa Clara, CA, USA) (Fu et al, 2011;Miyazaki et al, 2012). The values of a field blank were less than ∼ 24 % of the concentration of these molecular compounds in the ambient samples.…”

“…Ocean-derived submicron particles contain a large fraction of water-soluble OC (WSOC), which can significantly alter the hygroscopic property of aerosols (Prather et al, 2013) and act as CCN and IN. Only a few studies have used the 13 C of WSOC for source apportionment (Fisseha et al, 2009;Kirillova et al, 2010;Miyazaki et al, 2012). The WSOC-specific 13 C analysis in combination with organic molecular markers provides robust tools for the source apportionment of WSOC in marine aerosols.…”