With importance to both climate change and air quality, the proposed effort will augment the Program for Research on Oxidants: Photochemistry, Emissions, and Transport (PROPHET) at UMBS. PROPHET is well-suited for studies of forest-atmosphere interactions and the influence of transported urban pollution on remote locations. This project will add measurements of greenhouse gases and atmospheric particles to characterize the remote forest ecosystem in northern Michigan. Real-time measurements of the size and chemistry of individual atmospheric particles will be conducted using a single-particle mass spectrometer. Concurrent particle collection will allow detailed chemistry and morphology characterization via electron microscopy and microspectroscopy. Observations of methane and ethane will also be made, enabling both the quantification of regional methane emissions and attribution to natural or anthropogenic sources. Tentatively, size-resolved aerosol number concentration measurements will also be made at the Lakeside lab for a comparison with PROPHET.