Antarctic new particle formation from continental biogenic precursors

Abstract

Abstract. Over Antarctica, aerosol particles originate almost entirely from marine areas, with minor contribution from long-range transported dust or anthropogenic material. The Antarctic continent itself, unlike all other continental areas, has been thought to be practically free of aerosol sources. Here we present evidence of local aerosol production associated with melt-water ponds in continental Antarctica. We show that in air masses passing such ponds, new aerosol particles are efficiently formed and these particles grow up to sizes where they may act as cloud condensation nuclei (CCN). The precursor vapours responsible for aerosol formation and growth originate very likely from highly abundant cyanobacteria Nostoc commune (Vaucher) communities of local ponds. This is the first time freshwater vegetation has been identified as an aerosol precursor source. The influence of the new source on clouds and climate may increase in future Antarctica, and possibly elsewhere undergoing accelerating summer melting of semi-permanent snow cover.

Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice

“…Aerosols and their precursors in the Antarctic region originate predominantly from marine and sea-ice areas, with only one recent study reporting aerosols sourced from local meltpond cyanobacteria (Kyrö et al, 2013). The sea-ice region experiences high biological productivity (Moore and Abbott, 2000), with products such as dimethyl sulfide (DMS) and other organic species readily available as potential precursors for particle production.…”

“…Measurements at Cape Grim Baseline Air Pollution Station (CG-BAPS) show summer averages of 944 ± 504 cm −3 , similar to those observed in this springtime study, however measurements in spring at CGBAPS are substantially lower at 562±417 cm −3 (Jimi et al, 2007). There are numerous CN 10 measurements reported in the literature for Antarctic stations, all with median values below 275 cm −3 , the highest of which are found at coastal stations (Kyrö et al, 2013;Järvi-nen et al, 2013;Hansen et al, 2009;Hara et al, 2011a). It is important to note that in the Antarctic region, CN 3 concentrations show a small peak in spring, with an annual maximum in summer (e.g.…”

Features in air ions measured by an air ion spectrometer (AIS) at Dome C

“…7). In general, such events are characterized by a disappearance of aerosol particles from the measured particle size range (Komppula et al, 2005;Kyrö et al, 2013). Additionally, a sudden drop in the cluster ion concentration has been reported as a feature for cloud activation events (Lihavainen et al, 2007).…”

“…Air ion number size distributions in the size range from < 1 nm up to about 40 nm have been measured at Aboa in the coastal Antarctica during several summer campaigns (Virkkula et al, 2007;Asmi et al, 2010;Kyrö et al, 2013), but not on the upper plateau. The high altitude of Dome C means that the Concordia station is more exposed to cosmic radiation than the coastal sites in Antarctica.…”

“…Number size distributions of aerosol particles have been measured during short-term campaigns, mainly at coastal stations (e.g. Ito, 1993;Koponen et al, 2003;Virkkula et al, 2007;Asmi et al, 2010;Pant et al, 2011;Belosi et al, 2012;Kyrö et al, 2013;Weller et al, 2015), but also on the upper plateau at the South Pole (e.g. Park et al, 2004).…”