The aim of this study is to characterize the composition and seasonal variations of water-soluble organic compounds present in the atmospheric aerosol in the surroundings of a municipal waste incinerator (MWI) near to Bologna, a great urban centre in Northern Italy. This study is a part of an intensive environmental and epidemiological monitoring program (MONITER project) that has been designed and developed by the Environmental Protection Agency of Emilia Romagna Region (ARPAER), in order to evaluate the impact of the MPWI emissions on the ambient air and to estimate the exposure levels to toxic or carcinogenic compounds for a population living in the neighbourhood of this incinerator. Samples were collected during intensive summer 2008 and winter 2009 campaigns in 8 monitoring sites selected in order to compare points where the incinerator has the highest impact with those where the incinerator impact is negligible. The analyzed compounds included 18 dicarboxylic acids and 7 sugars, as important chemical tracers that may give relevant information on the relative strengths of primary emission sources and secondary photochemical processes affecting air quality. In both the seasons the most abundant compound is levoglucosan, as the major by-product from biomass burning. The abundances of the main dicarboxylic acids -- C3-C9 n-alkanoic and pthalic acids --exhibit a seasonal pattern with higher winter concentrations (mean total concentrations are were 60±18 and 23±9 , in winter and summer, respectively). The distribution profiles and the diagnostic ratios of these markers allowed to identify primary emission sources (power plants, vehicular circulation, biomass burning) associated with secondary constituents from both biogenic (e.g. pinonic acid) and anthropogenic precursors (e.g. phthalic and benzoic acids). The distinct seasonal patterns of abundances suggests that the contribution of primary sources is significantly enhanced in winter in comparison with summer, when secondary atmospheric processes are dominant This result is consistent with the winter atmospheric conditions in Po valley, caracterized by lower mixing heights, possible formation of the inversion layers, and less chance of wet deposition that confine vertical distribution of pollutants to the first hundred meters of the atmosphere contributing to the accumulation of air pollutants. Consequently, the secondary production of diacids is promoted by higher abundance of the organic precursors.
Spatial and seasonal distribution of dicarboxylic acids and sugars in the surroundings of a municipal waste incinerator near Bologna, Italy
PIETROGRANDE, Maria Chiara;BACCO, Dimitri;
2012
Abstract
The aim of this study is to characterize the composition and seasonal variations of water-soluble organic compounds present in the atmospheric aerosol in the surroundings of a municipal waste incinerator (MWI) near to Bologna, a great urban centre in Northern Italy. This study is a part of an intensive environmental and epidemiological monitoring program (MONITER project) that has been designed and developed by the Environmental Protection Agency of Emilia Romagna Region (ARPAER), in order to evaluate the impact of the MPWI emissions on the ambient air and to estimate the exposure levels to toxic or carcinogenic compounds for a population living in the neighbourhood of this incinerator. Samples were collected during intensive summer 2008 and winter 2009 campaigns in 8 monitoring sites selected in order to compare points where the incinerator has the highest impact with those where the incinerator impact is negligible. The analyzed compounds included 18 dicarboxylic acids and 7 sugars, as important chemical tracers that may give relevant information on the relative strengths of primary emission sources and secondary photochemical processes affecting air quality. In both the seasons the most abundant compound is levoglucosan, as the major by-product from biomass burning. The abundances of the main dicarboxylic acids -- C3-C9 n-alkanoic and pthalic acids --exhibit a seasonal pattern with higher winter concentrations (mean total concentrations are were 60±18 and 23±9 , in winter and summer, respectively). The distribution profiles and the diagnostic ratios of these markers allowed to identify primary emission sources (power plants, vehicular circulation, biomass burning) associated with secondary constituents from both biogenic (e.g. pinonic acid) and anthropogenic precursors (e.g. phthalic and benzoic acids). The distinct seasonal patterns of abundances suggests that the contribution of primary sources is significantly enhanced in winter in comparison with summer, when secondary atmospheric processes are dominant This result is consistent with the winter atmospheric conditions in Po valley, caracterized by lower mixing heights, possible formation of the inversion layers, and less chance of wet deposition that confine vertical distribution of pollutants to the first hundred meters of the atmosphere contributing to the accumulation of air pollutants. Consequently, the secondary production of diacids is promoted by higher abundance of the organic precursors.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
