9616438 Bertman Peroxyacyl nitrates (PANs) are a major component of total oxidized nitrogen in the atmosphere. More effort is needed to understand their formation, loss and distribution, as well as their impact on local, regional, and global atmospheric chemistry. Measurements of PANs can be sensitive probes of regional influence and of global issues related to pollutant transport. In this project, a dedicated and automated analytical instrument system for measurement of tropospheric PAN and its analogs will be constructed, installed, and operated at the University of Michigan Biological Station (UMBS) located near Pellston, Michigan. PANs will be measured using automated gas chromatography with electron capture detection. The UMBS site allows investigating many questions regarding atmospheric ozone chemistry in the Midwest. Air masses reaching this site are transported either from rural areas or from the industrial/metropolitan areas in the south. The project will have a strong collaborative component since it will be co-located with measurements of ozone, carbon monoxide, nitrogen oxides, organic nitrates, isoprene, carbonyls, meteorological parameters, etc., performed by other scientists. These comprehensive measurements will also allow detailed speciation of reactive nitrogen. The PAN measurements will contribute towards a better understanding of the seasonal fluctuations of nitrate photoproducts, the mechanism of isoprene photochemistry during different seasons, and the photochemical and transport mechanisms that result in the observed species distributions.
