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 2014e2015 austral summer. A six-stage high-volume cascade impactor with size classes between 10 mm and 0.49 mm, and, in parallel, for comparison purposes, a PM10 high-volume sampler (50% cut-off aerodynamic diameter of 10 mm) 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): Dp < 0.49 mm, 0.33 (0.26e0.34) mgm3; 0.49e0.95 mm, 0.20 (0.19e0.24) mgm3; 0.95e1.5 mm, 0.16 (0.13e0.21) mgm3; 1.5e3.0 mm 0.075 (0.05e0.11) mg m3; 3.0e7.2 mm 0.12 (0.02e0.19) mg m3; 7.2e10 mm 0.06 (0.01e0.03) mg m3. The average mass concentration of the total PM10 at Faraglione Camp for the entire sampling period was 0.92 (0.67e1.1) mg m3. Although a great variability, the aerosol mass concentration showed a tri-modal distribution, with an accumulation mode (in the range 0.1e1.0 mm) and two coarse modes (CM1 in the range 1.0e3.0 mm, and CM2 in the range 3.0e10 mm). From 50% to 90% of the PM10 mass comes from particles of a size smaller than 1.0 mm. The two coarse modes represented from ~5% to ~35% of the PM10, showing opposite seasonal trends (CM1 decreased while CM2 increased). During summer, PM10 mass concentration increased to a maximum of ~1.6 mg m3 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 PM10 peak of mid-summer.
Evolution of size-segregated aerosol mass concentration during the Antarctic summer at Northern Foothills, Victoria Land / Illuminati, Silvia; Bau, Sébastien; Annibaldi, Anna; Mantini, Caterina; Libani, Giulia; Truzzi, Cristina; Scarponi, Giuseppe. - In: ATMOSPHERIC ENVIRONMENT. - ISSN 1352-2310. - 125:(2016), pp. 212-221. [10.1016/j.atmosenv.2015.11.015]