Atmospheric VOC measurements at a High Arctic site: characteristics and source apportionment

Jakob B Pernov,Henrik Skov,Jacob K Nøjgaard,Rossana Bossi,Jens L Hjorth,Thibaut Lebourgeois,Rupert Holzinger

doi:10.5194/acp-21-2895-2021

Abstract

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.

Highlights

The temperature in the Arctic has increased at twice the rate of the global average (IPCC, 2019), a phenomenon known as Arctic amplification
While biomass burning is a source of black carbon (BC) globally, which is expected to increase in the future (Westerling et al, 2006), the results presented here indicate that meteorological parameters encountered during transport can play a role in the levels observed in the High Arctic atmosphere
volatile organic compounds (VOCs) mixing ratios were measured during April–October 2018 at the High Arctic Villum Research Station located at Station Nord in northeast Greenland

Summary

Introduction

The temperature in the Arctic has increased at twice the rate of the global average (IPCC, 2019), a phenomenon known as Arctic amplification. The background factor explains the majority (> 50 %) of the variation of acetone and C5H8O as well as 37 % of formaldehyde (Fig. 8a). Acetone and formaldehyde are known to have photochemical oxidation of precursor compounds in the atmosphere as an important source. The species profile for the background factor corresponds to mixing ratios of 0.355 ppbv for acetone, 0.090 ppbv for formaldehyde, and less than 0.050 ppbv for all other compounds.

Objectives

Methods

Results

Conclusion