COMPOSITION ANALYSES OF SIZE-RESOLVED AEROSOL SAMPLES TAKEN FROM AIRCRAFT DOWNWIND OF KUWAIT, SPRING 1991

Analyses are reported for eight aerosol samples taken from the National Center for Atmospheric Research Electra typically 200 to 250 km downwind of Kuwait between May 19 and June 1, 1991. Aerosols were separated into fine (D(p) < 2.5 mum) and coarse (2.5 < D(p) 10 mum) particles for optical, gravimetric, X ray and nuclear analyses, yielding information on the morphology, mass, and composition of aerosols downwind of Kuwait. The mass of coarse aerosols ranged between 60 and 1971 mug/m3 and, while dominated by soil derived aerosols, contained considerable content of sulfates and salt (NaCl) and soot in the form of fluffy agglomerates. The mass of fine aerosols varied between 70 and 785 mug/m3, of which about 70% was accounted for via compositional analyses performed in vacuum. While most components varied greatly from flight to flight, organic matter and fine soils each accounted for about 1/4 of the fine mass, while salt and sulfates contributed about 10% and 7%, respectively. The Cl/S ratios were remarkable constant, 2.4 +/- 1.2 for coarse particles and 2.0 +/- 0.2 for fine particles, with one flight deleted in each case. Vanadium, when observed, ranged from 9 to 27 ng/m3, while nickel ranged from 5 to 25 ng/m3. In fact, fine sulfates, vanadium, and nickel occurred in levels typical of Los Angeles, California, during summer 1986. The V/Ni ratio, 1.7 +/- 0.4, was very similar to the ratios measured in fine particles from combusted Kuwaiti oil, 1.4 +/- 0.9. Bromine, copper, zinc, and arsenic/lead were also observed at levels between 2 and 190 ng/m3. The presence of massive amounts of fine, typically alkaline soils in the Kuwaiti smoke plumes significantly modified their behavior and probably mitigated their impacts, locally and globally.