253
Views
15
CrossRef citations to date
0
Altmetric
Original Articles

Variations of constituents of individual sea-salt particles at Syowa station, Antarctica

, , , , , & show all
Pages 230-246 | Received 20 Apr 2004, Accepted 18 Nov 2004, Published online: 18 Jan 2017
 

Abstract

Sampling of atmospheric aerosol particles was carried out at Syowa station, Antarctica (39.58°E, 69.00°S) in 1998. For a better understanding of sea-salt chemistry in the coastal Antarctic regions, individual sea-salt particles were analysed using a scanning electron microscope equipped with energy dispersive X-ray spectrometer (SEM-EDX). Individual particle analysis indicates that more sea-salt particles were modified in fine particles (0.2–2 µm in diameter) through heterogeneous reactions mainly with gaseous sulfur species in the summer and reactive nitrogen oxides in the winter—spring. In particular, sea-salt particles in the coastal Antarctic atmosphere may be modified by heterogeneous reactions with not only SO2 and H2SO4 but also volatile sulfur species (e.g. CH3SO3H, DMS and DMSO) derived from bioactivity on the ocean surface during the summer. Also, low air temperature and a larger extent of sea ice offshore Syowa probably enhanced release of fractionated sea-salt particles (S-rich, Mg-rich, K-rich and Ca-rich) from the surface of snow and sea ice, particularly in September—October 1998. In addition, we attempt to estimate the scavenging rate of atmospheric sulfur species and reactive nitrogen oxides by dry deposition of sea-salt particles. Our estimation suggests that the upper limit of the scavenging rate of atmospheric sulfur species by sea-salt particles could rise to approximately 0.5 nmol m2 day1 at Syowa station during the summer. This value corresponded to about 30% of the concentration of particulate sulfur species such as non-sea-salt (nss)-SO2−4 and CH3SO3 and ~10% of total atmospheric sulfur species (nss-SO2−4, CH3SO3 and SO2). In contrast, the estimated NO3 scavenging rate by sea-salt particles was ~0.2 nmol m2 day1, which is similar to the dry deposition rate of HNO3+N2O5 (approximately 0.2–0.3 nmol m2 day1). Hence, sea-salt particles probably play an important role as scavengers of acidic species in the coastal Antarctic regions.