Abstract. There are few long-term datasets of volatile organic compounds (VOCs) in the High Arctic. Furthermore, knowledge about their source regions remains lacking. To address this matter, we report a multiseason dataset of highly time-resolved VOC measurements in the High Arctic from April to October 2018. We have utilized a combination of measurement and modeling techniques to characterize the mixing ratios, temporal patterns, and sources of VOCs at the Villum Research Station at Station Nord in northeastern Greenland. Atmospheric VOCs were measured using proton-transfer-reaction time-of-flight mass spectrometry. Ten ions were selected for source apportionment with the positive matrix factorization (PMF) receptor model. A four-factor solution to the PMF model was deemed optimal. The factors identified were biomass burning, marine cryosphere, background, and Arctic haze. The biomass burning factor described the variation of acetonitrile and benzene and peaked during August and September. The marine cryosphere factor was comprised of carboxylic acids (formic, acetic, and C3H6O2) as well as dimethyl sulfide (DMS). This factor displayed peak contributions during periods of snow and sea ice melt. A potential source contribution function (PSCF) showed that the source regions for this factor were the coasts around southeastern and northeastern Greenland. The background factor was temporally ubiquitous, with a slight decrease in the summer. This factor was not driven by any individual chemical species. The Arctic haze factor was dominated by benzene with contributions from oxygenated VOCs. This factor exhibited a maximum in the spring and minima during the summer and autumn. This temporal pattern and species profile are indicative of anthropogenic sources in the midlatitudes. This study provides seasonal characteristics and sources of VOCs and can help elucidate the processes affecting the atmospheric chemistry and biogeochemical feedback mechanisms in the High Arctic.

Abstract. There are few long-term datasets of volatile organic compounds (VOCs) in the High Arctic. Furthermore, knowledge about their source regions remains lacking. To address this matter, we report a long-term dataset of highly time-resolved VOC measurements in the High Arctic from April to October 2018. We have utilized a combination of measurement and modeling techniques to characterize the mixing ratios, temporal patterns, and sources of VOCs at Villum Research Station at Station Nord, in Northeast Greenland. Atmospheric VOCs were measured using Proton Transfer-Time of Flight-Mass Spectrometry (PTR-ToF-MS). Ten ions were selected for source apportionment with the receptor model, positive matrix factorization (PMF). A four-factor solution to the PMF model was deemed optimal. The factors identified were Biomass Burning, Marine Cryosphere, Background, and Arctic Haze. The Biomass Burning factor described the variation of acetonitrile and benzene. Back trajectory analysis indicated the influence of active fires in North America and Eurasia. The Marine Cryosphere factor was comprised of carboxylic acids (formic, acetic, and propionic acid) as well as dimethyl sulfide (DMS). This factor displayed a clear diurnal profile during periods of snow and sea ice melt. Back trajectories showed that the source regions for this factor were the coasts around North Greenland and the Arctic Ocean. The Background factor was temporally ubiquitous, with a slight decrease in the summer. This factor was not driven by any individual chemical species. The Arctic Haze factor was dominated by benzene with contributions from oxygenated VOCs. This factor exhibited a maximum in the spring and minima during the summer and autumn. This temporal pattern and species profile are indicative of anthropogenic sources in the mid-latitudes. This study provides seasonal characteristics and sources of VOCs and can help elucidate the processes affecting the atmospheric chemistry and biogeochemical feedback mechanisms in the High Arctic.

<p>IAGOS (www.iagos.org) is a European research infrastructure using commercial aircraft to measure the atmospheric composition. In particular, IAGOS provides regular carbon monoxide (CO) data since December 2001. In this study we use eighteen years of available data (from 2002 to 2019) to investigate CO anomalies throughout the entire flight i.e. vertical profiles over airports and upper troposphere/lower stratosphere (UTLS) at cruise altitude.</p><p>IAGOS flight track is divided into four distinctive vertical groups: boundary layer, middle troposphere, upper troposphere and lower stratosphere. The entire IAGOS data set has been split in 18 regions according to the geographical variability (e.g. continents over northern mid-latitudes, tropics, etc ...) and the different seasonal cycles of CO. CO anomalies are defined as air masses with CO mixing ratios above the 95th/99th percentile of the regional/seasonal/vertical distribution. This unique data set allows us to look at the variety of CO anomalies between regions and seasons.</p><p>Soft-io module which couples emission inventories and Lagrangian modelling along IAGOS flight track is used to quantify in which proportion those anomalies are linked to biomass burning and anthropogenic emissions.</p><p>The origin of those events presents high seasonal discrepancies (drought season and cold season) but also inter-annual variabilities. Anomalies coming from anthropogenic sources hit the most heavily on the lower part of the atmosphere of densely populated areas. However, none of the region, whatever the altitude range, are spared by anthropogenic pollution. Anomalies coming from biomass burning present large regional variability caused by weather conditions and biomass differences. We quantified these local and temporal variabilities to better understand processes affecting CO anomalies in the troposphere and UTLS.</p>