The eastern U.S. is a major source of ozone and ozone precursors to the North Atlantic region. Previous studies have shown that emissions from this region significantly affect levels of NOx and hydrocarbons over the Western North Atlantic Ocean, and recent measurements indicate that transport of ozone produced over the eastern U.S substantially alters the ozone budget of the temperate North Atlantic region. However the total impact of anthropogenic emissions on the photochemistry of this region is currently poorly understood. A primary reason is a paucity of information on NOx (NO + NO2) and total reactive nitrogen levels over the central and eastern North Atlantic, which results in uncertainty as to the ultimate fate and impact of anthropogenic emissions on the regional ozone budget. This project seeks to address this problem through measurements of NO and NOy (total reactive nitrogen oxides) at a site in the Azores. The location is ideal for observation of aged emissions transported from eastern North America and is suitably isolated from European impacts. Measurements would be made in conjunction with a currently-planned CO (carbon) and O3 (ozone) monitoring program, and would take place in concert with the other measurement programs in order to assess seasonal variations. The resulting data would be used to quantify anthropogenic impacts on NOx and ozone levels in the North Atlantic troposphere.
