Atmospheric and Climate Sciences, 2015, 5, 266-274 Published Online July 2015 in SciRes. http://www.scirp.org/journal/acs http://dx.doi.org/10.4236/acs.2015.53020 How to cite this paper: Gantt, B., Glotfelty, T., Meskhidze, N. and Zhang, Y. (2015) Simulating the Impacts of Marine Or- ganic Emissions on Global Atmospheric Chemistry and Aerosols Using an Online-Coupled Meteorology and Chemistry Mod- el. Atmospheric and Climate Sciences, 5, 266-274. http://dx.doi.org/10.4236/acs.2015.53020 Simulating the Impacts of Marine Organic Emissions on Global Atmospheric Chemistry and Aerosols Using an Online-Coupled Meteorology and Chemistry Model Brett Gantt 1,2 , Timothy Glotfelty 1 , Nicholas Meskhidze 1 , Yang Zhang 1* 1 Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, USA 2 Now at Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research Triangle Park, Raleigh, USA Email: * yang_zhang@ncsu.edu Received 4 June 2015; accepted 4 July 2015; published 7 July 2015 Copyright © 2015 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/ Abstract To realistically simulate the impacts of marine isoprene and primary organic aerosols (POA) on atmospheric chemistry, a unified model framework with online emissions, comprehensive treat- ment of gas-phase chemistry, and advanced aerosol microphysics is required. In this work, the global-through-urban WRF/Chem model (GU-WRF/Chem) implemented with the online emissions of marine isoprene and size-resolved marine POA is applied to examine such impacts. The net ef- fect of these emissions was increased surface concentrations of isoprene and organic aerosols and decreased surfaced concentrations of hydroxyl radical and ozone over most marine regions. With the inclusion of these emissions, GU-WRF/Chem better predicted the surface concentrations of isoprene and organic aerosols and the aerosol number size distribution when compared to mea- surements in clean marine conditions. Keywords Marine Organic Emissions, Marine Organic Aerosol, Atmospheric Chemistry, Online-Coupled Model, GU-WRF/Chem 1. Introduction The chemical composition and aerosols of the natural background atmosphere are important to model predictions * Corresponding author.