Particulate trimethylamine in the summertime Canadian high Arctic lower troposphere

Abstract

Abstract. Size-resolved and vertical profile measurements of single particle chemical composition (sampling altitude range 50-3000 m) were conducted in July 2014 in the Canadian high Arctic during an aircraft-based measurement campaign (NETCARE 2014). We deployed the single particle laser ablation aerosol mass spectrometer ALABAMA (vacuum aerodynamic diameter range approximately 200-1000 nm) to identify different particle types and their mixing states. On the basis of the single particle analysis, we found that a significant fraction (23 %) of all analyzed particles (in total: 7412) contained trimethylamine (TMA). Two main pieces of evidence suggest that these TMA-containing particles originated from emissions within the Arctic boundary layer. First, the maximum fraction of particulate TMA occurred in the Arctic boundary layer. Second, compared to particles observed aloft, TMA particles were smaller and less oxidized. Further, air mass history analysis, associated wind data and comparison with measurements of methanesulfonic acid give evidence of a marine-biogenic influence on particulate TMA. Moreover, the external mixture of TMAcontaining particles and sodium and chloride ("Na / Cl-") containing particles, together with low wind speeds, suggests particulate TMA results from secondary conversion of precursor gases released by the ocean. In contrast to TMAcontaining particles originating from inner-Arctic sources, particles with biomass burning markers (such as levoglucosan and potassium) showed a higher fraction at higher altitudes, indicating long-range transport as their source. Our measurements highlight the importance of natural, marine inner-Arctic sources for composition and growth of summertime Arctic aerosol.

Organic functional groups in the submicron aerosol at 82.5° N, 62.5° W from 2012 to 2014

“…S6), but there are significant differences: Factor 4 has a lower CoD with EC, lower contributions from alcohol and alkane groups, and higher contributions from acid groups and amine groups. Amine groups show little association with Regions 1 and 1467 (Table 2), and the highest CoD for amine groups in Table 3 is with ss-Na + : recent observations suggest a secondary Arctic marine source of particulate amine coincident with but in smaller sizes than sea-salt particles (Köllner et al, 2017). Also, Factor 4 is the dominant factor associated with the anomalously high nss-SO = 4 during the last 2 months of the study, when EC was relatively low.…”

“…During April, August and September of 2012, there were a number of forest fires in Siberia (e.g., Gorchakov et al, 2014). In July 2014, fires in Siberia (NASA Earth Observatory) and the NWT were carried north, with the NWT fires reaching at least as far as Resolute Bay, Nunavut (Köllner et al, 2017). One other week, centered on 20 July 2012, had relatively high EC (65 ng m −3 ) and OM (340 ng m −3 ; 2.3 times nss-SO = 4 ).…”

“…Amine groups can have marine sources (Facchini et al, 2008;Köllner et al, 2017) as well as anthropogenic sources. Here, the strongest associations of the amine groups are with ss-Na + for the dark and spring weeks (Table 3).…”

“…Their organic functional group (OFG) analyses showed the winterspring OM consisted primarily of alkane and carboxylic acid groups from combustion sources and carbohydrate-like substances hypothesized to be from sea spray in spring and frost flower formation associated with new sea ice formation in winter (Shaw et al, 2010;Russell et al, 2010). Marine sources further contribute to OM in spring and summer through emissions of biogenic volatile organic compounds (BVOCs; e.g., isoprene and terpenes) that are oxidized in the atmosphere (Fu et al, 2009a), oxygenated VOCs (OVOCs; Mungall et al, 2017) and trimethylamines (Köllner et al, 2017) as well as from direct emissions of sea spray Frossard et al, 2011Frossard et al, , 2014. During winter and early spring, much of the OM may come from Eurasian fossil fuel sources (e.g., Behrenfeldt et al, 2008;Nguyen et al, 2013;Barrett et al, 2015), and it is mixed with sulfates and nitrates (Weinbruch et al, 2012).…”

Characterization of transport regimes and the polar dome during Arctic spring and summer using in situ aircraft measurements

“…Transport into the Arctic and especially into the Arctic lower troposphere is possible along different pathways, depending on the source area of air masses and the time of the year (Klonecki, 2003;Stohl, 2006;Law and Stohl, 2007;AMAP, 2015). Stohl (2006) identified three major pathways that significantly contribute to transport from major pollution sources into the Arctic lower troposphere.…”