The goal of the proposed work is to answer the following specific scientific questions: (1) How do biogenic emissions affect the processing and export efficiency of NOx emissions through organic nitrates? What is the role of terpenes in global oxidation? (2) What is the impact of nighttime processes, such as the isoprene+NO3 and terpenes+NO3 reactions and aerosol uptake of NO3/N2O5, on daytime ozone, NOy partitioning and nitrogen export efficiency? (3) What is the response of tropospheric ozone to projected future changes in anthropogenic activities (e.g., NOx emissions) and biogenic emissions? How do global OH concentrations and CH4 lifetime respond to these changes? (4) Does this new BVOCs oxidation chemistry lead to an improved understanding of preindustrial levels of tropospheric ozone?