Evolution of size-segregated aerosol mass concentration during the Antarctic summer at Northern Foothills, Victoria Land

Autor: Anna Annibaldi, Caterina Mantini, Sébastien Bau, Cristina Truzzi, Silvia Illuminati, Giuseppe Scarponi, Giulia Libani
Rok vydání: 2016
Předmět:
Zdroj: Atmospheric Environment. 125:212-221
ISSN: 1352-2310
DOI: 10.1016/j.atmosenv.2015.11.015
Popis: Within the framework of the Italian National Programm for Antarctic Research (PNRA), the first direct gravimetric measurements of size-segregated aerosol fractions were carried out at Faraglione Camp, ∼3-km far from the Italian station “M. Zucchelli” (Terra Nova Bay, Ross Sea), during the 2014–2015 austral summer. A six-stage high-volume cascade impactor with size classes between 10 μm and 0.49 μm, and, in parallel, for comparison purposes, a PM 10 high-volume sampler (50% cut-off aerodynamic diameter of 10 μm) were used. A 10-day sampling strategy was adopted. Aerosol mass measurements were carried out before and after exposure by using a microbalance specifically designed for the filter weight and placed inside a glove bag in order to maintain stable temperature and humidity conditions during weighing sessions. Measured atmospheric concentrations (referred to the “actual air conditions” of mean temperature of 268 K and mean pressure of 975 hPa) of size-segregated aerosol fractions showed the following values, given as size range, means (interquartile range): D p −3 ; 0.49–0.95 μm, 0.20 (0.19–0.24) μg m −3 ; 0.95–1.5 μm, 0.16 (0.13–0.21) μg m −3 ; 1.5–3.0 μm 0.075 (0.05–0.11) μg m −3 ; 3.0–7.2 μm 0.12 (0.02–0.19) μg m −3 ; 7.2–10 μm 0.06 (0.01–0.03) μg m −3 . The average mass concentration of the total PM 10 at Faraglione Camp for the entire sampling period was 0.92 (0.67–1.1) μg m −3 . Although a great variability, the aerosol mass concentration showed a tri-modal distribution, with an accumulation mode (in the range 0.1–1.0 μm) and two coarse modes (CM1 in the range 1.0–3.0 μm, and CM2 in the range 3.0–10 μm). From 50% to 90% of the PM 10 mass comes from particles of a size smaller than 1.0 μm. The two coarse modes represented from ∼5% to ∼35% of the PM 10 , showing opposite seasonal trends (CM1 decreased while CM2 increased). During summer, PM 10 mass concentration increased to a maximum of ∼1.6 μg m −3 at mid-December, while in January it decreased to values that are typical of November. Both accumulation and upper super-micron fractions showed a maximum in the same period contributing to the PM 10 peak of mid-summer.
Databáze: OpenAIRE
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