Articles | Volume 17, issue 17
Research article
14 Sep 2017
Research article |  | 14 Sep 2017

Contributions of transported Prudhoe Bay oil field emissions to the aerosol population in Utqiaġvik, Alaska

Matthew J. Gunsch, Rachel M. Kirpes, Katheryn R. Kolesar, Tate E. Barrett, Swarup China, Rebecca J. Sheesley, Alexander Laskin, Alfred Wiedensohler, Thomas Tuch, and Kerri A. Pratt

Abstract. Loss of sea ice is opening the Arctic to increasing development involving oil and gas extraction and shipping. Given the significant impacts of absorbing aerosol and secondary aerosol precursors emitted within the rapidly warming Arctic region, it is necessary to characterize local anthropogenic aerosol sources and compare to natural conditions. From August to September 2015 in Utqiaġvik (Barrow), AK, the chemical composition of individual atmospheric particles was measured by computer-controlled scanning electron microscopy with energy-dispersive X-ray spectroscopy (0.13–4 µm projected area diameter) and real-time single-particle mass spectrometry (0.2–1.5 µm vacuum aerodynamic diameter). During periods influenced by the Arctic Ocean (70 % of the study), our results show that fresh sea spray aerosol contributed  ∼ 20 %, by number, of particles between 0.13 and 0.4 µm, 40–70 % between 0.4 and 1 µm, and 80–100 % between 1 and 4 µm particles. In contrast, for periods influenced by emissions from Prudhoe Bay (10 % of the study), the third largest oil field in North America, there was a strong influence from submicron (0.13–1 µm) combustion-derived particles (20–50 % organic carbon, by number; 5–10 % soot by number). While sea spray aerosol still comprised a large fraction of particles (90 % by number from 1 to 4 µm) detected under Prudhoe Bay influence, these particles were internally mixed with sulfate and nitrate indicative of aging processes during transport. In addition, the overall mode of the particle size number distribution shifted from 76 nm during Arctic Ocean influence to 27 nm during Prudhoe Bay influence, with particle concentrations increasing from 130 to 920 cm−3 due to transported particle emissions from the oil fields. The increased contributions of carbonaceous combustion products and partially aged sea spray aerosol should be considered in future Arctic atmospheric composition and climate simulations.

Short summary
Arctic sea ice loss is leading to increasing petroleum extraction and shipping. It is necessary to identify emissions from these activities for improved Arctic air quality and climate assessment. Atmospheric particles were measured from August to September 2015 in Utqiaġvik, AK. For periods influenced by Prudhoe Bay, significant influence associated with combustion emissions was observed, compared to fresh sea spray influence during Arctic Ocean periods.
Final-revised paper