Factors Governing the Atmospheric Deposition of Polycyclic Aromatic Hydrocarbons to Remote Areas

Abstract

Polycyclic aromatic hydrocarbons (PAH) were measured in bulk atmospheric deposition collected in three remote areas of Europe during 1997-1998. Mean total PAH fluxes over a period of 18 months were 1560 +/- 750 and 1150 +/- 630 ng m(-2) mo(-1) in the Pyrenees and the Alps, respectively. In the Caledonian mountains (Scandinavia) the observed mean fluxes were 1900 +/- 940 ng m(-2) mo(-1) (6 month collection). Similar qualitative PAH compositions (p values <0.05) in the bulk atmospheric deposition have been observed between sites, which are dominated by the more volatile parent compounds. The main differences between lakes are related to the high molecular weight compounds. Atmospheric deposition of PAH to these remote sites appears to be independent of their concentrations in the atmosphere, which are similar between sites (in the range of 1.8-3.0 ng x m(-3)), being controlled mainly by particle deposition, followed by precipitation and air temperature. A multilevel regression model including these three variables accounted for 74% of the total variability in total PAH bulk deposition; however, the contribution of each variable in the model is compound and site-dependent. The deposition of high molecular weight PAH depends more on particle deposition and precipitation, whereas air temperature is the main factor controlling the deposition fluxes of the low molecular weight PAH.

Drivers of atmospheric deposition of polycyclic aromatic hydrocarbons at European high altitude sites

“…Deposited PAHs may re-volatilize, be transported over long distances and be deposited again on soil and water surfaces far from the emission sources (Fernández et al, 2003), e.g.…”

“…Only in a few cases has deposition been considered in remote areas such as high altitude regions (Fernández et al, 2003;Offenthaler et al, 2009;Foan et al, 2012). However, high mountain areas provide the reference background information of the pollution impact, in this case PAHs, of the overall anthropogenic activities in large regions.…”

“…These compounds are also the most abundant in the atmosphere, namely in the gas phase (Fernández 270 et al, 2002). Dominance of LMW-PAH in atmospheric deposition and, particularly, phenanthrene, fluoranthene and pyrene, is a common feature of studies in Europe (Halsall et al, 1997;Holoubek et al, 2007;Fernández et al, 2003;Cetin et al, 2016), America (Gigliotti et al, 2005;Brun et al, 2004) and Asia (Li et al, 2009;Wang et al, 2011b;Sharma et al, 2018).…”

Increasing and decreasing trends of the atmospheric deposition of organochlorine compounds in European remote areas during the last decade

“…However, there is evidence that even these areas receive impacts of long-range atmospheric transported pollutants such as POPs (Blais et al, 1998;Wang et al, 2009;Estellano et al, 2008;Fernández and Grimalt, 2003;Fernández et al, 1999;Daly and Wania, 2005). As observed in the polar regions (Cabrerizo et al, 2012;Halsall, 2004), field studies in Europe , western Canada (Davidson et al, 2003), South America (Grimalt et al, 2004a;Pozo et al, 2007) and the Tibetan Plateau among others, have shown that mountains can act as cold-traps for POPs or even organic compounds with limited atmospheric transport, e.g.…”

“…Atmospheric deposition is the main pathway by which POPs are incorporated into pristine regions (Carrera et al, 2002;Fernández et al, 2003). Unfortunately, there are substantial gaps of knowledge concerning the specific transfer mechanisms occurring at these sites, such as the influence of the physical-chemical properties of the trapped compounds and the environmental factors that are relevant for the overall deposition efficiencies.…”