Spatial distribution and source characteristics of volatile organic compounds (VOCs) in the northern hemispheric high latitude marine environment

Abstract

The atmospheric VOCs play key roles linked to the climate feedback thus knowing their distribution and source characteristics in the Arctic are important since this area is known to be the most vulnerable place to climate change on the globe. However direct measurement efforts to constraint on these aspects remain poor due to the difficulties in access. To provide more observational basis, total 38 species of VOCs were measured onboard R/V Araon from July to September 2021 by Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-ToFMS) and categorized into 6 sources (Araon stack, Siberian wildfire, port and gas-oil field, unknown 1 and 2, as well as marine background) based on their VOCs speciation patterns. The plume from Araon stack using the marine gas oil (MGO) as a fuel emitted xylene with high maximum concentration (up to 15.041 ppb). While, benzene and acetonitrile were good indicators of Siberian wildfire (up to 17.992 and 3.219 ppb, respectively). Benzene and toluene in along with high methane (up to 0.968, 0.549, and 2110 ppb in order) were important signs of the port and gas-oil field (i.e. Pevek port and Prudhoe Bay field) while hydrogen sulfide (up to 0.727 ppb) were more enhanced from gas-oil field than the port. Two unknown air masses with different VOCs compositions than other plumes (i.e. elevated 1-butene for both but toluene and xylene for one) presume to be originated from Araon activities were also characterized. In addition, VOCs species fractionation were compared by sea area as marine background air. Further researches on the origin of VOCs over the Arctic Ocean, initiated by this work, should be continued as it serves as a fundamental basis for mechanical understanding on the rapid climate response in this region.