Biogenic VOC from terrestrial vegetation (e.g., isoprene, monoterpenes) and biogenic marine sulfur compounds (e.g., dimethyl sulfide, DMS) undergo rapid nocturnal degradation in the presence of the nitrate radical, NO3. Since NO3 is derived from NOx, an anthropogenic pollutant, these oxidative processes represent an anthropogenic perturbation of a biogenic atmospheric input. These perturbations can have important consequences, such as the formation of organic and sulfate aerosol that affect Earth's climate. These processes have been studied through field studies from ships (New England), aircraft (New England, Texas, the Southeast), ground sites (Colorado,Alabama) and in large environmental chambers.