US Environmental Protection Agency (EPA) / National Exposure Research Laboratories (NERL) / Human Exposure and Atmospheric Sciences Division (HEASD)

EPA-approved 47 mm Teflon filters with unique identification numbers stamped on the polypropylene support ring and Teflon filters are weighed, handled, and deployed in accordance with the EPA PM 2.5 Chemical Speciation Network. This project involves a Rupprecht & Patashnik (R&P) Dichotomous Partisol-Plus Model 2025 automated sequential dichotomous sampler collection system, that is capable of collecting a minimum of seven days of particulate samples without operator assistance. Sampling only occurs, however, during down slope wind conditions at MLO.

The objectives are to accumulate a long-term record of fine (<2.5 µm) and coarse (2.5 – 10 µm) particulate chemistry to support receptor-modeling analysis of source-receptor relationships for mercury.