The PAH and Nitro-PAH Concentration Profiles in Size-Segregated Urban Particulate Matter and Soil in Traffic-Related Sites in Catania, Italy

Abstract

Polycyclic aromatic hydrocarbons (PAHs) and nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) were identified from both air particulate matter and soils. For air sampling, a six-stage cascade impactor was situated in an urban area (Catania, Italy) that is recognized for its high traffic volume. The soil samples were collected every 1.5 km from under the grass by the side of the median of a Catania road along its full length (8.2 km). HPLC in electrochemical-fluorescence detection mode was used for selective separation, identification and quantification of analytes in air and soil samples, providing both good selectivity and sensitivity. The seasonal trends, effects of urban traffic, and source profiles are discussed herein. Higher PM₁₀ concentrations were observed for summer (43 μg m⁻³) in comparison to winter (24 μg m⁻³). Conversely, the PAHs contained in PM₁₀ were higher in winter (0.48 ng m⁻³ for fluoranthene) than in summer (0.14 ng m⁻³ for fluoranthene). Analysis of the size-segregated urban particulate matter showed that the amount of PM_0.5 (stage 6) was always higher than the amount of other particles (stages 1–5). Furthermore, the PM_0.5 was always higher in summer (about 40%, m/m) than in winter (about 30%, m/m). Finally, the amounts of PAH and nitro-PAH in PM_0.5 (stage 6) were always higher, by a maximum of one order of magnitude, than that of other particles (stages 1–5). This result is crucial because ultrafine particles have a tendency to move into the blood through the alveolar epithelial barrier. Moreover, the air and soil pollution levels agree with those found in other cities with similar levels of pollution. Supplemental materials are available for this article. Go to the publisher's online edition of Polycyclic Aromatic Compounds to view the supplemental file.

Key Words:

• nitro-PAH
• PAH
• PM
• seasonal trend
• soil

Acknowledgments

Financial support from MIUR (PRIN 2009) is gratefully acknowledged. Gratitude also extends to Dr. Alessandra Castaldo for soil sampling, treatment, and analysis.