Sources of anions in aerosols in northeast Greenland during late winter

Abstract

The knowledge of climate effects of atmospheric aerosols is associated with large uncertainty, and a better understanding of their physical and chemical properties is needed, especially in the Arctic environment. The objective of the present study is to improve our understanding of the processes affecting the composition of aerosols in the high Arctic. Therefore size-segregated aerosols were sampled at a high Arctic site, Station Nord (Northeast Greenland), in March 2009 using a Micro Orifice Uniform Deposit Impactor. The aerosol samples were extracted in order to analyse three water-soluble anions: chloride, nitrate and sulphate. The results are discussed based on possible chemical and physical transformations as well as transport patterns. <br><br> The total concentrations of the ions at Station Nord were 53–507 ng m<sup>−3</sup>, 2–298 ng m<sup>−3</sup> and 535–1087 ng m<sup>−3</sup> for chloride (Cl<sup>−</sup>), nitrate (NO<sub>3</sub><sup>−</sup>) and sulphate (SO<sub>4</sub><sup>2−</sup>), respectively. The aerosols in late winter/early spring, after polar sunrise, are found to be a mixture of long-range transported and regional to local originating aerosols. Fine particles, smaller than 1 μm, containing SO<sub>4</sub><sup>2−</sup>, Cl<sup>−</sup> and NO<sub>3</sub><sup>−</sup>, are hypothesized to originate from long-range transport, where SO<sub>4</sub><sup>2−</sup> is by far the dominating anion accounting for 50–85% of the analyzed mass. The analysis suggests that Cl<sup>−</sup> and NO<sub>3</sub><sup>−</sup> in coarser particles (> 1.5 μm) originate from local/regional sources. Under conditions where the air mass is transported over sea ice at high wind speeds, very coarse particles (> 18 μm) are observed, and it is hypothesized that frost flowers on the sea ice are a source of the very coarse nitrate particles

Biogenic and Anthropogenic sources of Arctic Aerosols

“…During the entire campaign, SO4 2is the dominant species that on average makes up almost 70% of the 295 PM1 mass concentration measured by the SP-AMS (average 1.5 µg m -3 , Figure 1.b-c). This is in accordance with previous findings for SO4 2at VRS based on measurements with lower time-resolution (Nguyen et al, 2013;Fenger et al, 2013;Heidam et al, 2004). Atmospheric SO4 2is mainly formed as secondary inorganic aerosols and only a minor fraction is from primary emissions (Massling et al, 2015).…”

“…A major part of the aerosol mass is long-range transport from source regions outside the Arctic where the primary source region has been identified as the northern part of Eurasia (Nguyen et al, 2013;Quinn et al, 2008;Heidam et al, 2004;Stohl et al, 2007;Christensen, 1997). Studies have shown that main constituents of Arctic aerosols are sulfate (SO4 2-) and organics mixed with a minor fraction of nitrate 70 (NO3 -), ammonium (NH4 + ), black carbon (BC) and heavy metals (Quinn et al, 2007;Fenger et al, 2013;Nguyen et al, 2013;Frossard et al, 2011;Barrie et al, 1981). This is also the case at the high Arctic station, Villum Research Station (VRS) at Station Nord in North Greenland, where this study was conducted.…”

Biogenic and anthropogenic sources of aerosols at the High Arctic site Villum Research Station

“…These fragments are often taken as being indicative of anhydrous sugar such as levoglucosan and thereby suggest that biomass burning makes some contribution to Arctic OA. However, SOA also contributed to the abundance of C 2 H 4 O + 2 (Aiken et al, 2008Cubison et al, 2011;Lee et al, 2010;Saarnio et al, 2013). Quantitatively, the expected abundance of C 2 H 4 O + 2 from SOA did not exceed the measured concentration in this study.…”

Frost flower aerosol effects on Arctic wintertime longwave cloud radiative forcing

“…While Roscoe et al . [] found that frost flowers were very stable at high wind speeds up to 12 m s −1 , this might have been because the laboratory conditions were not representative of the Arctic [ Fenger et al ., ]. Yang et al .…”

“…An alternative is that frost flowers may contribute to the high salt loading during winter and early spring in polar regions when young sea ice (e.g., nilas, leads) replaces open water near coastal sampling sites [Rankin et al, 2000[Rankin et al, , 2002Rankin and Wolff, 2003]. While Roscoe et al [2011] found that frost flowers were very stable at high wind speeds up to 12 m s À1 , this might have been because the laboratory conditions were not representative of the Arctic [Fenger et al, 2013]. Yang et al [2008] suggested blowing snow as a potential aerosol source, while Nghiem et al [2012] challenged this view for the Arctic.…”