Atmospheric transport and deposition of pesticides are issues of significant concern. The presence of pesticides in rain implicates their presence in air, yet few, if any studies have analyzed ambient air for multiple residues of pesticides currently used. Atmospheric transport may be another important route of exposure to the general public and to sensitive, non-target ecosystems. This study will concurrently determine pesticides in air and rainfall at three sites - one farm, one urban, and one - to initially characterize agricultural and urban effects, and local and regional transport effects. Analytes include the pesticides commonly used in Iowa. A staggered sampling interval will characterize seasonal and temporal changes related to application periods. This project will develop some of the first data on year round ambient air pesticide concentrations. The findings will be the basis for expanded studies of exposure assessment, fate and transport, and non-target ecosystem effects.