Atmospheric concentrations and gas-particle partitions of pesticides: Comparisons between measured and gas-particle partitioning models from source and receptor sites

Atmospheric concentrations and gas-particles partition were measured for 83 pesticides including organochlorines (OCs), acid herbicides (AHs), neutral herbicides (NHs) and organophosphorus pesticides (OPs). Samples have been collected in June 2005 at two sites, located in Québec, named St. Anicet (agricultural area) and Bay St. François wetland (receptor site). The highest vapor concentration was measured for metolachlor which was 23,600 pg m−3 and 12,200 pg m−3 at St. Anicet and Bay St. François (BSF), respectively. In the particulate phase, MCPA exhibited the highest level (323 pg m−3) at St. Anicet.Gas-particle partitions (GPPs) were also investigated and it was expressed as a function of the fraction of chemical in the particulate phase (ϕ). The highest average of ϕ was observed for the AHs which were MCPB (75%) and MCPA (50%) at BSF and St. Anicet, respectively.Likewise, the GPPs were estimated by several models, namely Junge–Pankow model, KOA model, and polyparameter linear free energy relationships (ppLFERs). The estimated GPPs were compared to the observed ones and data showed a better correlation at BSF (receptor site) than that at St. Anicet. This suggests a kinetic effect on the GPPs of chemicals.