Evaluation of Nitrated Polycydic Aromatic Hydrocarbons in Anthropogenic Emission and Air Samples: A Possible Means of Detecting Reactions of Carbonaceous Particles in the Atmosphere

Abstract

Speciation of all mononitrofluoranthene/pyrene isomers, made possible by using a DB 17 capillary column, has permitted a fair evaluation of these components in several mobile and stationary sources that might have a significant impact in urban areas. A comparison between the distribution of these nitrated polycyclic aromatic hydrocarbons in dust collected from various emission sources and that found in particulate matter collected in a urban area of Central Italy indicates that from the spring to late autumn months, when the weather is mild, gas phase reactions, occurring in the atmosphere, lead to the formation of substantial amounts of 2-nitrofluoranthene/pyrene isomeric pairs. Dust collected under different conditions show, instead, that 3-, 8-nitrofluoranthene isomers can also be present as major products. Since the concentration of these components in the emission sources investigated is lower than that observed in atmospheric samples, conversion through gas with particle reactions is proposed as a possible mechanism to explain the difference observed.