Organic contaminants in the atmosphere of Ny-Ålesund

In-field measurements of atmospheric contaminants were undertaken in 1998 and 1999. Our concern was focused on organic chemicals, as important contributors to ambient toxicity, tracers of sources and indicators of meteo-climatic contour. As for gaseous chemicals, focus was on semi-volatile aldehydes; among particulate organics, n-alkanes, PAHs and Nitro-PAHs were investigated. Carbonyls were collected on June 1998 on Zeppelin mount (ZM) and at CNR Scientific Base CSB). Samplings lasted 2 h, starting at 8:00 h, and contaminants were collected on silica gel cartridges loaded with pentafluorophenyl hydrazine (PFPH). Degradation of hydrazones was prevented by applying ozone scrubbers. Characterization of C3-C14 aldehydes was carried out through GC-MS analysis [Cecinato et al., Chromatographia 54 (2001), 263]. Formaldehyde, acetaldehyde and acetone were not determined due to interferences. Suspended particulates (PM10 fraction) were collected at high-volume conditions on quartz filters, during summer 1998 and spring 1999. In 1998 a pair of 3-day sampling periods were undertaken in June (sunny hours); in 1999 (April-May) three sampling periods were selected, each day between last night and sunrise. Organic fraction was extracted in ultra-sonic bath, separated into three fractions through alumina column chromatography (non-polar aliphatics, polycyclic aromatics and polar organics), and analyzed for contents in n-alkanes, PAHs, Nitro-PAHs and fatty acids by means of GC-MSD. About carbonyl during June 1998, the concentrations at the two locations investigated were different and showed important daily variability. Also their percent profiles and concentration ratios between the two stations changed widely. Total carbonyls ranged ~8-45 µg/m3 at ZM and ~2-7 µg/m3 at CSB. The concentrations of n-alkanes in PM10 were different in 1998 and 1999 (~19 vs. 100 ng/m3 as period average), as well as percent distribution of <C24 homologues. According to that, in the summer bacteria and microorganisms provided important contribution to n-alkane occurrence, whilst in spring the petroleum exhausts were predominating. The emission of vegetation was scarce (CPI25≈1.4). Total PAHs were, as average, more in Apr-May 1999 (~1.4 vs. 0.6 ng/m3) and distinct distributions were identified. It could depend in part on ambient temperature (semi-volatile compounds are enriched on particulate during winter). Nonetheless, a role was played also by the nature of emission sources (as suggested by changes in PAH concentration ratios), while reactivity of the atmosphere was unimportant (BaP/BeP ratio). Though only nitrated fluoranthenes and pyrenes were investigated, Nitro-PAHs merited concern. Nitro-PAHs were more in the spring (~135 vs. 10 pg/m3) and, overall, the percent profiles were very different: 1-, 7-, 3-NFAs and 1-NPY, typical of direct emission, occurred in spring, 2-NFA and 2-NPY (generated by photochemical reactions) in the summer. Fatty acids (ranging ~20-40 ng/m3 as total)were indicative of bacterial and small vegetation sources.