AIRCRAFT MEASUREMENTS OF SULFUR, NITROGEN, AND CARBON SPECIES DURING WATOX-86

Filter pack and aethalometer systems were successfully used aboard the National Oceanic and Atmospheric Administration WP-3D and King Air aircraft during the January 1986 intensive field investigation of the Western Atlantic Ocean Experiment (WATOX) to measure concentrations of sulfur and nitrogen species and black carbon aerosol. The mean boundary layer concentrations of SO4 =-e, NO3-, NH4+ and black carbon measured on the WP-3D were 16, 6.6, 23 and 16 nmol m(-3) (STP), respectively, and those of SO2 and HNO3 were 0.9 and 0.1 parts per billion by volume (ppbv), respectively. Mean boundary layer concentrations of SO4 = -e, NH4+ and HNO3 measured on the King Air were 20 nmol m(-3) (STP), 41.4 nmol m(-3) (STP) and 0.13 ppbv, respectively. Concentrations in the free troposphere were consistently lower by factors of 1.5 to 4.5 than those in the boundary layer. In the boundary layer SO4 = -e accounted for approximately 30% of the total non-sea-salt sulfur, and particulate NO3- accounted for 40% of the total nitrate. NH4+ and SO4 = -e were significantly correlated and present in a molar ratio of approximately 2:1, suggesting that the species existed in the aerosol primarily as (NH4)(2)SO4.