An Investigation of the Sources of Summertime Haze in the Blue Ridge Mountains Using Multivariate Statistical Methods

Abstract

Multivariate statistical analyses are employed to identify the source areas of the fine particulates and sulfate, which are the primary components of summer haze in the Blue Ridge Mountains of Virginia. These analyses include principal component analysis followed by stepwise multiple regression analysis. The results indicate that most of the fine particles and sulfates originate in the Midwest. The most important factor for both parameters is the residence time of the air parcels over the Midwest. The results also indicate that the sulfate is formed by photochemically initiated reactions. Production of organic aerosols from natural hydrocarbon emissions is also identified as a minor source of fine particles in the Blue Ridge Mountains area.