Polycyclic aromatic hydrocarbons (PAHs) and their nitrated and oxygenated derivatives in the Arctic boundary layer: seasonal trends and local anthropogenic influence

Tatiana Drotikova,Alena Dekhtyareva,Alexandre Albinet,Roland Kallenborn

doi:10.5194/acp-21-14351-2021

Abstract

Abstract. A total of 22 polycyclic aromatic hydrocarbons (PAHs), 29 oxy-PAHs, and 35 nitro-PAHs (polycyclic aromatic compounds, PACs) were measured in gaseous and particulate phases in the ambient air of Longyearbyen, the most populated settlement in Svalbard, the European Arctic. The sampling campaign started in the polar night in November 2017 and lasted for 8 months until June 2018, when a light cycle reached a sunlit period with no night. The transport regimes of the near-surface, potentially polluted air masses from midlatitudes to the Arctic and the polar boundary layer meteorology were studied. The data analysis showed the observed winter PAC levels were mainly influenced by the lower-latitude sources in northwestern Eurasia, while local emissions dominated in spring and summer. The highest PAC concentrations observed in spring, with PAH concentrations a factor of 30 higher compared to the measurements at the closest background station in Svalbard (Zeppelin, 115 km distance from Longyearbyen), were attributed to local snowmobile-driving emissions. The lowest PAC concentrations were expected in summer due to enhanced photochemical degradation under the 24 h midnight sun conditions and inhibited long-range atmospheric transport. In contrast, the measured summer concentrations were notably higher than those in winter due to the harbour (ship) emissions.

Highlights

Polycyclic aromatic hydrocarbons (PAHs) are toxic and carcinogenic compounds (International Agency for Research on Cancer, 2010; Kim et al, 2013) released into the atmosphere primarily through incomplete combustion of fossil fuels and biomass (Ravindra et al, 2008)
Large seasonal variations were observed for all the PACs, and the 20 polycyclic aromatic hydrocarbons (PAHs) concentration trend was found to differ from the long-term observations at the background station at Zeppelin mountain (Fig. S3) in Ny-Ålesund, Svalbard, located 115 km northwest of Longyearbyen
The results obtained here from air samples collected within a polar boundary layer at an urban site revealed the importance of anthropogenic emissions within the Arctic, which caused a different seasonal trend of PAC concentrations

Summary

Introduction

Polycyclic aromatic hydrocarbons (PAHs) are toxic and carcinogenic compounds (International Agency for Research on Cancer, 2010; Kim et al, 2013) released into the atmosphere primarily through incomplete combustion of fossil fuels and biomass (Ravindra et al, 2008). PAHs, nitro- and oxy-PAHs (polycyclic aromatic compounds, PACs) are semivolatile compounds partitioning between gaseous and particulate phases in response to ambient pressure and temperature and have different photolysis rates and long-range atmospheric transport (LRAT) potentials (Mulder et al, 2019; Tomaz et al, 2016; Albinet et al, 2007, 2008; Keyte et al, 2013; Nalin et al, 2016; Huang et al, 2014; Odabasi et al, 1999; Shahpoury et al, 2016). The PACs that escape the listed sink processes disperse via LRAT to remote places, including the Arctic

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