Evaluation of δ13C in Carbonaceous Aerosol Source Apportionment at a Rural Measurement Site

Abstract

The stable isotope of carbon, 13 C, has been used in several studies for source characterization of carbonaceous aerosol since there are specific signatures for different sources. In rural areas, the influence of different sources is complex and the application of δ 13 C for source characterization of the total carbonaceous aerosol (TC) can therefore be difficult, especially the separation between biomass burning and biogenic sources. We measured δ 13 C from 25 filter samples collected during one year at a rural background site in southern Sweden. Throughout the year, the measured δ 13 C showed low variability (-26.73 to -25.64‰). We found that the measured δ 13 C did not correlate with other commonly used source apportionment tracers ( 14 C, levoglucosan). δ 13 C values showed lower variability during the cold months compared to the summer, and this narrowing of the δ 13 C values together with elevated levoglucosan concentrations may indicate contribution from sources with lower δ 13 C variation, such as biomass or fossil fuel combustion. Comparison of two Monte Carlo based source apportionment models showed no significant difference in results when δ 13 C was incorporated in the model. The insignificant change of redistributed fraction of carbon between the sources was mainly a consequence of relatively narrow range of δ 13 C values and was complicated by an unaccounted kinetic isotopic effect and overlapping δ 13 C end-member values for biomass burning and biogenic sources.

Seasonal study of stable carbon and nitrogen isotopic composition in fine aerosols at a Central European rural background station

“…This broad range can be explained by the influence of marine aerosols (Ceburnis et al, 2016), different anthropogenic sources (e.g., Widory et al, 2004) as well as different distributions of C 3 and C 4 plants (Martinelli et al, 2002), resulting in different δ 13 C values in the Northern Hemisphere and Southern Hemisphere (Cachier, 1989). The δ 13 C values at the Košetice site fall within the range common to other European sites: for example, a rural background site in Vavihill (southern Sweden, range −26.7 ‰ to −25.6 ‰, Martinsson et al, 2017), urban Wrocław (Poland, range −27.6 ‰ to −25.3 ‰, Górka et al, 2014), different sites (urban, coastal, forest) in Lithuania (eastern Europe, Masalaite et al, 2015Masalaite et al, , 2017, as well as urban Zurich (Switzerland, Fisseha et al, 2009a).…”

“…Thus, the relatively low δ 13 C values in our range (up to −28.9 ‰) are because fine particles have lower δ 13 C values in comparison with coarse particles probably due to different sources of TC. (e.g., Masalaite et al, 2015;Skipitytė et al, 2016).…”

“…Górka et al (2014) used δ 13 C in TC in conjunction with polyaromatic hydrocarbon (PAH) analyses for P. Vodička et al: Seasonal study of stable carbon and nitrogen isotopic composition 3465 the determination of the sources of PM 10 organic matter in Wrocław, Poland, during the vegetative and heating seasons. Masalaite et al (2015) used an analysis of δ 13 C in TC on size-segregated urban aerosols to elucidate carbonaceous PM sources in Vilnius, Lithuania. Fewer studies have been conducted on δ 13 C in aerosols in rural and remote areas of Europe.…”

Responses to the comments of Referee #2

“…This broad range can be explained by the influence of marine aerosols (Ceburnis et al, 2016), different anthropogenic sources (e.g., Widory et al, 2004) as well as different distributions of C 3 and C 4 plants (Martinelli et al, 2002), resulting in different δ 13 C values in the Northern Hemisphere and Southern Hemisphere (Cachier, 1989). The δ 13 C values at the Košetice site fall within the range common to other European sites: for example, a rural background site in Vavihill (southern Sweden, range −26.7 ‰ to −25.6 ‰, Martinsson et al, 2017), urban Wrocław (Poland, range −27.6 ‰ to −25.3 ‰, Górka et al, 2014), different sites (urban, coastal, forest) in Lithuania (eastern Europe, Masalaite et al, 2015Masalaite et al, , 2017, as well as urban Zurich (Switzerland, Fisseha et al, 2009a).…”

On the Relationship of Biogenic Primary and Secondary Organic Aerosol Tracer Compounds on the Aethalometer Model Parameters

“…BVOCs are used as communicative tool as well as to handle abiotic and biotic stress and is emitted globally in large quantities from terrestrial and aquatic plants (Gabric et al, 2001;Penuelas and Llusia, 2003;Sharkey et al, 2008;Monson et al, 2013;Glasius and Goldstein, 2016;Steinke et al, 2018). Emissions of BPOA and BVOCs have been shown to increase with increasing photosynthetically active radiation (PAR) and temperature (Guenther et al, 1993;Guenther et al, 1995;Hakola et al, 2003), which explains the dominance of the biogenic mass fraction in carbonaceous aerosol during summer (Gelencser et al, 2007;Genberg et al, 2011;Yttri et al, 2011;Martinsson et al, 2017a;Martinsson et al, 2017b). The main BVOC is isoprene, which is emitted mostly from deciduous forests with an annual emission rate of 400-600 Tg y -1 (Laothawornkitkul et al, 2009).…”