In the framework of the“Supersito”project, three intensive experimental campaigns were conducted in the Po Valley (Northern Italy) in cold seasons, such as late autumn, pre-winter and deep-winter, over three years from 2011 to 2013. As a part of a study on polar marker compounds, including carboxylic acids, sugar derivatives and lignin phenols, the present study reports a detailed discussion on the at-mospheric concentrations of 14 low molecular weight carboxylic acids, mainly dicarboxylic and oxo-hydroxy carboxylic acids, as relevant markers of primary and secondary organic aerosols. PM2.5samples were collected in two monitoring sites, representing urban and rural background sta-tions. The high acid concentrations can be explained by the large human emission sources in the urbanized region, combined with the stagnant atmospheric conditions during the cold seasons that accumulate the organic precursors and accelerate the secondary atmospheric reactions. The distribution profiles of the investigated markers suggest the dominant contributions of primary anthropogenic sources, such as traffic, domestic heating and biomass burning. These results are confirmed by comparison with additional emission tracers, such as anhydro-saccharides for biomass burning and fatty acids originated from different anthropogenic sources. In addition, some secondary constituents were detected in both sites, as produced by in situ photo-chemical reactions from both biogenic (e.g. pinonic acid) and anthropogenic precursors (e.g. phthalic and adipic acids). The impact of different sources from human activities was elucidated by investigating theweek pattern of carboxylic and fattyacid concentrations. Theweekly trends of analytes during the warmer campaign may be related to emissions from motor vehicle traffic and industrial activities. Otherwise, the random pattern of the markers suggests the prevalent contribution of primary emissions from residential heating in the colder deep-winter.
Polar organic marker compounds in atmospheric aerosol in the PoValley during the Supersito campaigns. Part 1: Low molecular weight carboxylic acids in cold seasons
PIETROGRANDE, Maria Chiara;BACCO, Dimitri;VISENTIN, Marco;
2014
Abstract
In the framework of the“Supersito”project, three intensive experimental campaigns were conducted in the Po Valley (Northern Italy) in cold seasons, such as late autumn, pre-winter and deep-winter, over three years from 2011 to 2013. As a part of a study on polar marker compounds, including carboxylic acids, sugar derivatives and lignin phenols, the present study reports a detailed discussion on the at-mospheric concentrations of 14 low molecular weight carboxylic acids, mainly dicarboxylic and oxo-hydroxy carboxylic acids, as relevant markers of primary and secondary organic aerosols. PM2.5samples were collected in two monitoring sites, representing urban and rural background sta-tions. The high acid concentrations can be explained by the large human emission sources in the urbanized region, combined with the stagnant atmospheric conditions during the cold seasons that accumulate the organic precursors and accelerate the secondary atmospheric reactions. The distribution profiles of the investigated markers suggest the dominant contributions of primary anthropogenic sources, such as traffic, domestic heating and biomass burning. These results are confirmed by comparison with additional emission tracers, such as anhydro-saccharides for biomass burning and fatty acids originated from different anthropogenic sources. In addition, some secondary constituents were detected in both sites, as produced by in situ photo-chemical reactions from both biogenic (e.g. pinonic acid) and anthropogenic precursors (e.g. phthalic and adipic acids). The impact of different sources from human activities was elucidated by investigating theweek pattern of carboxylic and fattyacid concentrations. Theweekly trends of analytes during the warmer campaign may be related to emissions from motor vehicle traffic and industrial activities. Otherwise, the random pattern of the markers suggests the prevalent contribution of primary emissions from residential heating in the colder deep-winter.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
