Particulate organic compounds in the atmosphere surrounding an industrialised area of Prato (Italy)

Atmospheric aerosols were collected during the period from May 2000 through January 2001 at 13 different sites in and around the Baciacavallo sewage treatment plant in Prato (Italy). The urban area surrounding the plant contains significant textile industrial activity and a main arterial road. Aerosol-associated n-alkane, polycyclic aromatic hydrocarbon (PAH), nonylphenol (NP) and nonylphenolethoxylate (NPnEO) (n=1–3) concentrations were measured in order to evaluate contributions from the sewage treatment plant, naturally produced aerosols, transportation and industrial activities to the air quality in the vicinity of the sewage treatment plant. Aerosol-associated n-alkane concentrations ranged from 36.7 to 205 ng/m3 and their possible origin was determined by the presence of typical petroleum characteristics such as the unresolved complex mixture and an odd/even carbon ratio (Carbon Preference Index). PAH concentrations ranged from 0.855 to 24.2 ng/m3, in accordance with those generally found for urban aerosols in Europe. NP and NPnEO (n=1–3), as well as fine aerosol particulate matter (PM10) were significantly correlated with relative wind direction with increased levels observed in the ambient atmosphere when the relative wind direction was from the Baciacavallo sewage treatment plant. This study confirms the use of NP and NPnEO (n=1–3) as markers of sewage treatment emissions and the importance of the contribution of aerosols produced by sewage treatment plant aeration tanks to the local atmospheric composition.