ABSTRACT
This chapter summarizes the photochemical reactivity of polycyclic aromatic hydrocarbons (PAHs) deposited from the vapor phase onto "intact" and "fractionated" coal ashes of diverse origin and properties. Subsequent to release into the atmosphere, PAHs and their derivatives may undergo transformation; both photochemical and nonphotochemical processes may be important. The chemical fate of a PAH in the particulate phase may depend on the physical properties and/or chemical composition of the surface on which it is sorbed. The phototransformation of five PAHs (pyrene, benzoapyrene, anthracene, benzaanthracene, and phenanthrene) deposited from the vapor phase onto eight stack ashes has been examined. Six of these ashes were derived from combustion of eastern Appalachian, east Tennessee, western Kentucky, and Illinois bituminous coals; New Mexico subbi-tuminous coal; and Texas lignite. The chapter examines numerous aspects of the chemistry of particle-associated PAHs. For example, little is known about the effects of sorption on particles of the reactivity of PAHs with reactive atmospheric species.
