Biogenic and Anthropogenic sources of Arctic Aerosols

Abstract

<p><strong>Abstract.</strong> There are limited measurements of the chemical composition, abundance, and sources of black carbon (BC) containing particles in the high Arctic. To address this, we report 93 days of Soot Particle Aerosol Mass Spectrometer (SP-AMS) data collected in the high Arctic. The period spans from February 20th until May 23rd 2015 at Villum Research Station (VRS) in Northern Greenland (81°36' N). Particulate sulfate (SO<sub>4</sub><sup>2−</sup>) accounted for 66 % of the non-refractory PM<sub>1</sub>, which amounted to 2.3 µg m<sup>−3</sup> as an average value observed during the campaign. The second most abundant species was organic matter (24 %), averaging 0.55 µg m<sup>3</sup>. Both organic aerosol (OA) and PM<sub>1</sub>, estimated from the sum of all collected species, showed a marked decrease throughout May in accordance with Arctic haze leveling off. The refractory black carbon (rBC) concentration averaged 0.1 µg m<sup>−3</sup> over the entire campaign.</p> <p>Positive Matrix Factorization (PMF) of the OA mass spectra yielded three factors: (1) a Hydrocarbon-like Organic Aerosol (HOA) factor, which was dominated by primary aerosols and accounted for 12 % of OA mass; (2) an Arctic haze Organic Aerosol (AOA) factor, which accounted for 64 % of the OA and dominated until mid-April while being nearly absent from the end of May; and (3) a more oxygenated Marine Organic Aerosol (MOA) factor, which accounted for 22 % of OA. AOA correlated significantly with SO<sub>4</sub><sup>2−</sup>, suggesting the main part of that factor being secondary OA. The MOA emerged late at the end of March, where it increased with solar radiation and reduced sea ice extent, and dominated OA for the rest of the campaign until the end of May. Important differences are observed among the factors, including the highest O/C ratio (0.95) and S/C ratio (0.011) for MOA – the marine related factor. Our data supports current understanding of the Arctic summer aerosols, driven mainly by secondary aerosol formation, but with an important contribution from marine emissions. In view of a changing Arctic climate with changing sea-ice extent, biogenic processes, and corresponding source strengths, highly time-resolved data are urgently needed in order to elucidate the components dominating aerosol concentrations.</p>

Large Summer Contribution of Organic Biogenic Aerosols to Arctic Cloud Condensation Nuclei

“…In general, it is known that particularly Arctic spring aerosol is acidic throughout the troposphere (Fisher et al, ). Specifically for the vicinity of VRS, it was recently described that acidic aerosol is present in spring, explained by high amounts of sulfuric acid (Nielsen et al, ). On the other hand, κ values in literature, such as those discussed above, indicate a rather high content of organic aerosol.…”

A local marine source of atmospheric particles in the High Arctic

“…In a recent study, we showed how the sub-micrometer ambient particle concentration, measured by a Soot Particle Aerosol Mass Spectrometer (SP-AMS), and its chemical composition changed from a mean of 2.3 μg m − 3 in February at the onset of the Arctic Haze period, to 1.2 μg m − 3 in May (Nielsen et al, 2019). In this period, biogenic sources became relatively more important than anthropogenic sources.…”

“…In terms of chemical composition, sulfate (SO 4 2− ) was the major component, comprising 66% of the non-refractory PM 1 , followed by organics, accounting for 24% of PM 1 . Using Positive Matrix Factorization (PMF) (Ulbrich et al, 2009;Zhang et al, 2011) and more specifically the PMF Evaluation Tool Software (PET, v2.08D; available online at http://cir es1.colorado.edu/jimenez-group/wiki/index.php/PMF-AMS_Analy-sis_Guide), Nielsen et al (2019) found that three factors explain the observed organic Aerosol (OA). First, Hydrocarbon-like Organic Aerosol (HOA, anthropogenic), characterized by hydrocarbon fragments from chemically reduced organic emissions and attributed to primary combustion sources of liquid, usually mostly fossil origin.…”

“…This parameter depends on the chemical composition and in particular the acidity and the water content of the aerosol (Matthew et al, 2008). In this work, a time-dependent CE averaging 0.85 was determined using the approach described by Middlebrook et al (2012), which is similar to a previous study at the same location in 2015 using an SP-AMS (Nielsen et al, 2019). To reduce the effect of ambient water content on the collection CE, a Nafion drier (Aerodyne Research) was connected to the ACSM inlet.…”

On the retrieval of aerosol optical depth over cryosphere using passive remote sensing

“…The chemical composition of Arctic Haze (Quinn et al, 2007) is largely determined by variety of process. Aerosol with Brown and Black Carbon is produced to a minor extend by the oxidation of natural sand anthropogenic missions of hydrocarbons and to a major extend by fires/ biomass burning (Heintzenberg et al, 1981;Quinn et al, 2007;Nielsen et al, 2019). Black carbon has been widely discussed in the literature (Hansen and Nazarenko, 2004;Ramanathan and Carmichael, 2008;Bond et al, 2013;Jacobi et al, 2019).…”