9414259 Milne A major focus of the third phase of AEROCE is to improve the understanding of the chemical processes occurring as polluted air masses move off the eastern North American continent. The presence of non-methane hydrocarbons (NHMCs) in these air masses, together with the oxides of nitrogen (NOx), leads to the photochemical production or destruction of ozone. Ozone is a radiatively important trace gas which has both biological and human health impacts. Together with the hydroxyl radical, OH, ozone is a key factor in regulating the oxidative capacity of the atmosphere, i.e. the processes whereby anthropogenic emissions, including NMHCs, are broken down and removed from the gas phase. As part of the AEROCE program, this will initiate measurements of speciated (C2 - C10) NMHCs in the marine atmosphere at several of the AEROCE field sites. The proposed field measurements will provide an integrated measurement setting with which to further understanding of the chemical climatology of NMHCs and photochemical oxidants in the North Atlantic troposphere.
