Modeling of population exposure to airborne pesticides

Air pollution due to pesticides emitted by farming practices is an environmental topical issue nowadays and little it’s known about its effects on human health. Pesticides can contaminate the atmosphere through various pathways, especially by volatilization and by adsorption on particulate matter. Although the use of certain substances (i.e. dichlorodiphenyltrichloroethane, DDT) has been banned over the years, there are still few groups of substances (i.e. phosphorganic insecticides, triazole and phenylenediamine fungicides applied on fruit orchards and vineyards) whose characteristics of toxicity, carcinogenicity, and persistence can lead to severe effects on human health. This paper shows a methodology for the modeling of the population exposure to airborne pesticides based on the AERMOD Gaussian air dispersion model and on geoprocessing and spatial analysis techniques implemented in a GIS (Geographic Information System) environment using the Python programming language. This analysis relies on several spatial data (i.e. hazard sources localization), appropriate processing and on management techniques achievable in a GIS environment. The methodology has been applied to a test site, located in Centre Po Valley near the city of Modena, Italy. In this territory several epidemiological studies have been carried out so far. These activities are framed in the context of a partnership between the DIEF and the CREAGEN of the University of Modena and Reggio Emilia. The main steps followed for the methodology can be summarized in: definition of the computational domain, realization of a GIS input geodatabase (hazard source localization, wind field, demography), realization of a Python procedure to allow the interaction between the GIS input dataset and AERMOD, data processing and visualization in a GIS environment. Fruit orchards and vineyards extracted from the Corine Land Cover have been modeled in AERMOD as areal hazard sources. The designed methodology allows to assess the spatial distribution in the test site of a relative concentration value associated to the use of phosphorganic insecticides, triazole and phenylenediamine fungicides in farming practices. In the future the parameterization of the hazard sources emission (currently only related to the area of the source) will be improved, in order to employ the methodology in epidemiological studies related to the occurrence of potential pathologies.