Polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and chlorinated pesticides in background air in central Europe – investigating parameters affecting wet scavenging of polycyclic aromatic hydrocarbons

Abstract

Abstract. Concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and chlorinated pesticides (CPs) were measured in air and precipitation at a background site in central Europe. ∑ PAH concentrations in air and rainwater ranged from 0.7 to 327.9 ng m−3 and below limit of quantification (< LOQ) to 2.1 × 103 ng L−1. The concentrations of PCBs and CPs in rainwater were < LOQ. ∑ PCB and ∑ CP concentrations in air ranged from < LOQ to 44.6 and < LOQ to 351.7 pg m−3, respectively. The potential relationships between PAH wet scavenging and particulate matter and rainwater properties were investigated. The concentrations of ionic species in particulate matter and rainwater were significantly correlated, highlighting the importance of particle scavenging process. Overall, higher scavenging efficiencies were found for relatively less volatile PAHs, underlining the effect of analyte gas-particle partitioning on scavenging process. The particulate matter removal by rain, and consequently PAH wet scavenging, was more effective when the concentrations of ionic species were high. In addition, the elemental and organic carbon contents of the particulate matter were found to influence the PAH scavenging.

Evaluation of a Conceptual Model for Gas-Particle Partitioning of Polycyclic Aromatic Hydrocarbons Using Polyparameter Linear Free Energy Relationships

“…The temperature dependency of θ is more pronounced for FLT, PYR, BAA, and CHR, as evident from data points scattered across the temperature range, particularly for samples from Kosětice; whereas for PHE and BBF the values of θ are close to zero and one, respectively. Median PM 10 concentration was higher at Urla than at Kosětice and Grenoble. In contrast, median f OM values were comparable across all sites, although higher maximum values were found for Kosětice and Grenoble.…”

“…10,56 Table S4 provides statistics on θ for selected PAHs, as well as ambient temperature, PM 10 concentrations, and the mass mixing ratios of OM, f OM , elemental carbon, f EC , ammonium sulfate, f (NH 4 ) 2 SO 4 , and ammonium chloride, f NH 4 Cl , in PM. Median θ values for semivolatile FLT, PYR, BAA, and CHR were higher for samples from Kosětice than for those from Grenoble and Urla (Table S4).…”

Snow scavenging and phase partitioning of nitrated and oxygenated aromatic hydrocarbons in polluted and remote environments in central Europe and the European Arctic

“…The total scavenging ratios (WT; unitless) calculated for the target N/OPAHs were 10 3 -10 4 (Table S4B), which fall 15 within the range suggested for removal of polyaromatic compounds through particle scavenging (Shahpoury et al, 2015). With the exception of 1,4-O2NAP and 9-OFLN, the calculated ratios are consistent with modelled Ө of 0.81-1 (at 273 K) for the target N/OPAHs (Table S4B) in that particle scavenging was the dominant removal mechanism.…”

“…It has been shown that the magnitude of particle scavenging is generally higher than gas scavenging for hydrophobic SOCs such as PAHs (Atlas and Giam, 1988;Bidleman, 1988;Shahpoury et al, 2015). In principle, for such substances one could apply Ө as an indicator for predicting the SOC wet particle scavenging -i.e.…”

“…is relevant for SOCs that show higher affinity towards particulate phase (Shahpoury et al, 2015). This is affected by SOC gas-particle partitioning (GPP) in the aerosol, a process controlled mainly by the substance molecular structure, PM chemical composition, and ambient temperature .…”