Aerosol and cloudwater properties at Whiteface mountain, New York

A Field program for the measurement of the physical and chemical properties of aerosols and clouds was conducted at Whiteface Mountain, N.Y., during an 8-week period in June, July, and August 1983. Analysis of two-stage Nuclepore filter samples by proton-induced X-ray emission (PIXE) spectroscopy showed that most (85 to 90%) of the aerosol sulfate was in the accumulation mode (modal radius r approximately equals 0.1 mu m) and that approximately equals 90% of total sulfate originated southwest of the Whiteface Mountain site. During a typical pollution episode originating in the Midwest, the total aerosol sulfate concentration was 19 mu g m super(-3), or 63% of total dry aerosol, which was approximately equals 30 mu g m super(-3). Scavenging of sulfate aerosol by clouds was found to be greater than 95% efficient in clouds of 0.5 g m super(-3) liquid water content. Measured pH values when the air mass trajectories were from the southwest were systematically lower than when the trajectories were from the northwest or northeast, i.e., 3.4 vs 4.4. and 4.8. In the southwest sector water samples, SO sub(4) super(-) super(2) and NO sub(3) super(-) were highly correlated to each other and to free H super(+), Ca sub(2) super(-), Cl super(-), Pb, and Ba.