Temporal variation in aerosol composition at summit, Greenland, summer 1989

Abstract

At a high altitude site at Summit, Greenland, aerosol sulfur, chlorine, and potassium were found to occur mainly during sporadic high concentration episodes, lasting less than 24 h, over a much lowwer background level. Particle size resolved time sequence sampling was performed by automated two-stage streaker and high sensitivity elemental analysis by proton induced X-ray emission, PIXE, with a detection limit of 9 ng m⁻³. In a series of 165 4-h samples during one summer month in 1989, peak concentrations in the fine <2 μm diameter fraction were sometimes coincident and sometimes not, indicating different degrees of association of those elements in air masses passing over the site. Most of the S, Cl, and K was measured during the short high concentration episodes. This finding could not have been made by using a long time average sampling strategy.