Regional Agency of Prevention and Environment ARPA Emilia Romagna

Italy

Regional Agency of Prevention and Environment ARPA Emilia Romagna

Italy
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Pietrogrande M.C.,University of Ferrara | Bacco D.,University of Ferrara | Visentin M.,University of Ferrara | Ferrari S.,Regional Agency of Prevention and Environment ARPA Emilia Romagna | Poluzzi V.,Regional Agency of Prevention and Environment ARPA Emilia Romagna
Atmospheric Environment | Year: 2014

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 atmospheric concentrations of 14 low molecular weight carboxylic acids, mainly dicarboxylic and oxo-hydroxy carboxylic acids, as relevant markers of primary and secondary organic aerosols.PM2.5 samples were collected in two monitoring sites, representing urban and rural background stations. The total quantities of carboxylic acids were 262, 167 and 249ngm-3 at the urban site and 308, 115, 248ngm-3 at the rural site in pre-winter, fall and deep-winter, respectively. These high 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 the week pattern of carboxylic and fatty acid concentrations. The weekly trends of analytes during the warmer campaign (fall 2012; mean temperature: 12°C) 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 (mean temperature: 5°C). © 2013 Elsevier Ltd.


Pietrogrande M.C.,University of Ferrara | Bacco D.,University of Ferrara | Visentin M.,University of Ferrara | Ferrari S.,Regional Agency of Prevention and Environment ARPA Emilia Romagna | Casali P.,Regional Agency of Prevention and Environment ARPA Emilia Romagna
Atmospheric Environment | Year: 2014

Four intensive experimental campaigns were conducted in the Po Valley (Northern Italy) in different seasons through the years 2012 and 2013, in the framework of the "Supersito" project. As a part of a study on polar tracers in atmospheric PM2.5, the present paper describes the abundances and temporal variations of sugars, as primary biogenic biomarkers, being the major form of photosynthetically assimilated carbon in the biosphere. The study includes primary saccharides (glucose, sucrose, arabinose, galactose and mycose), sugar alcohols (arabitol and mannitol) and anhydrosugars (levoglucosan, galactosan and mannosan).Strong seasonality was observed with total sugars concentration nearly 10 times higher in the cold seasons (mean 377ngm-3) than in summer/spring (mean 36ngm-3). Also sugar composition profiles varied seasonally, being dominated by anhydrosugars in fall and winter, i.e., levoglucosan (mean 271ngm-3), followed by mannosan (mean 53ngm-3) and galactosan (mean 29ngm-3). These data indicate that in the cold seasons the biomass combustion for domestic heating is the main sugar source representing nearly 94% of the total saccharides mass measured in PM2.5. Accordingly, glucose, arabinose and galactose show the highest concentrations, since these saccharides are also emitted during the burning process as uncombusted biomass materials. In spring/summer the primary saccharides are dominant in PM2.5, with mannitol as the most abundant, followed by mycose, glucose and ribitol that are emitted by the terrestrial biomass, reflecting the higher sugar production and utilization by the ecosystem in the warm seasons.These results were confirmed by investigating other molecular markers, such as low-molecular-weight carboxylic acids and n-alkane homologs. Principal Component Analysis was applied to the data to extract three PCs that may be attributed to different saccharide sources, such as biomass burning and primary bio aerosol. © 2014.

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