The ultimate impacts of VCP emissions on air quality, in particular ozone formation, are not well quantified though preliminary studies indicate that they do enhance concentrations of both ozone and secondary organic aerosol under certain conditions. A logical method to assess the impact of VCPs on ozone formation and concentrations would be to make extensive measurements of these compounds at one or more measurement sites and to simultaneously directly determine the instantaneous ozone formation rate. This project will do exactly that by deploying the ?ECHAMP? peroxy radical sensor to a site in upper Manhattan (CUNY Advanced Science Research Center) to join the New York City metropolitan Measurements of Emissions and TransformationS (NYC-METS) project. The goal of NYC-METS, which is already funded by NOAA AC4 and will run concurrently with AEROMMA, is to characterize the emissions and transformations of non-traditional organic compounds in New York City. Net ozone formation results from the reaction of peroxy radicals (HO2 and RO2) with nitric oxide (NO), forming photolabile nitrogen dioxide (NO2). By adding measurements of peroxy radicals to the NYC-METS suite of measurements, the project will be able to directly quantify the impact of VCPs on ozone formation in New York City.