The relationship of aerosol sulfate and relative humidity: a field study.

Abstract

Relative humidity and aerosol sulfate data were collected at the top of a tower (31 m) and at canopy height (22 m) in a forested area of northern Michigan during July 16, 2001 through July 23, 2001 with the purpose of observing the relationship between the relative humidity and aerosol sulfate size and mass. No obvious correlation was found when looking at the entire data set, however, when four-hour intervals were investigated, relationships between relative humidity and aerosol sulfate mass mean diameter, and relative humidity and total mass became evident. The correlation of total aerosol sulfate mass and relative humidity sometimes contradicted the correlation of aersol sulfate mass mean diameter and relative humidity, which may be an indication that there are other factors that affect aerosol sulfate mass and size. Because the effects of these external factors were present in some four-hour intervals, it is apparent that futher work should be done to avoid the effects of the external factors on the relationship between relative humidty and aerosol sulfate; to investigate shorter intervals under consistent meteorological conditions.