Distribution of VOCs between air and snow at the Jungfraujoch high alpine research station, Switzerland, during CLACE 5 (winter 2006)

Abstract

Abstract. Volatile organic compounds (VOCs) were analyzed in air and snow samples at the Jungfraujoch high alpine research station in Switzerland as part of CLACE 5 (CLoud and Aerosol Characterization Experiment) during February/March 2006. The fluxes of individual compounds in ambient air were calculated from gas phase concentrations and wind speed. The highest concentrations and flux values were observed for the aromatic hydrocarbons benzene (14.3 µg.m −2 s −1 ), 1,3,5-trimethylbenzene (5.27 µg.m −2 s −1 ), toluene (4.40 µg.m −2 s −1 ), and the aliphatic hydrocarbons i-butane (7.87 µg.m −2 s −1 ), ipentane (3.61 µg.m −2 s −1 ) and n-butane (3.23 µg.m −2 s −1 ). The measured concentrations and fluxes were used to calculate the efficiency of removal of VOCs by snow, which is defined as difference between the initial and final concentration/flux values of compounds before and after wet deposition. The removal efficiency was calculated at −24 • C (−13.7 • C) and ranged from 37% (35%) for o-xylene to 93% (63%) for i-pentane. The distribution coefficients of VOCs between the air and snow phases were derived from published poly-parameter linear free energy relationship (pp-LFER) data, and compared with distribution coefficients obtained from the simultaneous measurements of VOC concentrations in air and snow at Jungfraujoch. The coefficients calculated from pp-LFER exceeded those values measured in the present study, which indicates more efficient snow scavenging of the VOCs investigated than suggested by theoretical predictions.Correspondence to: E. Starokozhev

Retrievals of formaldehyde from ground-based FTIR and MAX-DOAS observations at the Jungfraujoch station and comparisons with GEOS-Chem and IMAGES model simulations

“…IMAGES v2 is a global CTM simulating the distributions of 132 trace compounds at a resolution of 2 × 2.5 • and at 40 hybrid pressure-sigma levels between the Earth's surface and the lower stratosphere (Stavrakou et al, 2009a(Stavrakou et al, , b, 2013. The model includes the chemistry of 22 precursor NMVOCs.…”

“…In summer, enhanced temperatures and insolation induce a higher photochemical oxidation rate of VOCs by the OH radicals, which results in increasing the HCHO formation. Moreover, the summer periods are also characterized by large biogenic emissions of NMVOCs that are high-yield HCHO precursors, such as isoprene, taking place in the continental boundary layer and originating from plants and temperate forests during the growing season in the Northern Hemisphere (e.g., Dufour et al, 2009b;Stavrakou et al, 2009a;Curci et al, 2010). More specifically at Jungfraujoch, Legreid et al (2008) reported measurements of higher concentrations in NMVOCs during summertime, which are attributed to secondary oxidation processes and higher emissions from biogenic sources essentially originating from northern Italy (because of the higher biogenic activity in this region compared to the north of the Alps).…”

Diurnal cycle and multi-decadal trend of formaldehyde in the remote atmosphere near 46° N

“…Formaldehyde has already been intensely observed, using measurements obtained from in situ instruments (e.g., de Serves, 1994;DiGangi et al, 2011DiGangi et al, , 2012, aircraft campaigns (e.g., Fried et al, 2002Fried et al, , 2008Fried et al, , 2011Frost et al, 2002;Wert et al, 2003) and various satellite sensors (e.g., Chance et al, 2000;Wittrock et al, 2006;Dufour et al, 2009a, b;Stavrakou et al, 2009aStavrakou et al, , b, 2015De Smedt et al, 2010Marais et al, 2012Marais et al, , 2014, as well as ground-based remote measurements derived from UV-Visible passive Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) instruments (e.g., Heckel et al, 2005;Pikelnaya et al, 2007;Inomata et al, 2008;Vigouroux et al, 2009;Irie et al, 2011;Wagner et al, 2011;Pinardi et al, 2013;Franco et al, 2015b) and from high-resolution infrared solar spectra recorded with Fourier transform infrared (FTIR) spectrometers (e.g., Mahieu et al, 1997;Notholt et al, 1997;Jones et al, 2009;Vigouroux et al, 2009;Paton-Walsh et al, 2010;Viatte et al, 2014;Franco et al, 2015b). However, few long-term trends of HCHO loadings exist that are suitable for trend analysis, particularly due to the lack of extended consistent data sets.…”

Contamination of Antarctic snow by polycyclic aromatic hydrocarbons dominated by combustion sources in the polar region

“…[21] Efficient snow scavenging of aromatic hydrocarbons, chlorinated hydrocarbons and monoterpenes from the atmosphere has been demonstrated for high altitudes. [22,23] Snow (firn) and ice core studies allow the assessment of temporal deposition trends. [24,25] PAH levels in the range of 36-660 ng L À1 were reported from an ice core in the Canadian Archipelago attributed to the years 1963-93 [26] and 0.6-237 ng kg À1 in an ice core from Greenland attributed to 1987-90.…”