Selection and ranking method for currently used pesticides (CUPs) monitoring in ambient air

Chronic exposure to pesticides can induce adverse human health effects. Even though ingestion is considered as the main exposure pathway, it is now suggested that inhalation might also be important not only in rural but also in urban locations. Therefore, assessment of currently used pesticides (CUPs) concentrations in ambient air is important for better understanding of human exposure through inhalation and potential health effects. Analytical methods do not allow assessing ambient air concentration of all the CUPs registered. Designing a cost-effective and a fitted-for-purpose monitoring strategy at the local/regional scale must therefore rely on a methodology allowing targeting CUPs by a ranking approach accounting for the most relevant selection criteria. In this study, after a first selection, a ranking method is used to identify most relevant CUPs for ambient air assessment in Wallonia, Belgium. This method took into account not only toxicological endpoints but also national and regional data on sales and uses along with other uses criteria. Moreover, probability to detect CUPs in ambient air was investigated using international, national, and regional studies and physicochemical properties. The ranking method used three main criteria (i.e., chronic toxicity, sales and uses, and presence in ambient air), which are divided in 17 sub-criteria, to provide the most accurate identification of CUPs that might be measured in ambient air and that might impact human health. After final selection based on analytical methods, 43 CUPs were further submitted to analytical method development.