The effect of Brown Carbon on thermal-optical analysis: a correction based on optical multi-wavelength analysis

Carbonaceous aerosol (CA) has an important impact on air quality, human health and climate change. Total Carbon (TC) is generally divided in organic carbon (OC) and elemental carbon (EC) (although a minor fraction of carbonate carbon (CC) may be present). This classification is based on their thermo-optical properties: while EC is strongly light absorbing, OC is generally transparent in the visible range except for some particular compounds. In fact, another fraction of light-absorbing organic carbon exists which is not black and is generally called brown carbon (BrC) (Andreae and Gelencs\ue9r, 2006). We recently introduced a new method to apportion the absorption coefficient (babs) of carbonaceous atmospheric aerosols starting from multi-wavelength optical analysis (Massab\uf2 et al., 2015). This analysis is performed by the MWAA, an instrument developed at the Physics Department of University of Genoa (Massab\uf2 et al., 2013) able to measure the aerosol absorption coefficient at 5 different wavelengths ranging from UV to IR. The method is based on the information gathered at these five different wavelengths, in a renewed and upgraded version of the approach usually referred to as Aethalometer model (Sandradewi et al., 2008). The resulting optical apportionment provides the quantification of EC and, with some assumptions, also of OC coming from fossil fuels and wood burning. Thermal-optical methods are presently the most widespread approach to OC/EC speciation. Despite their popularity, there is still a disagreement among the results, especially for what concerns EC as different thermal protocols can be used. In fact, the pyrolysis occurring during the analysis can heavily affect OC/EC separation, depending on PM composition in addition to the used protocol. Furthermore, the presence in the sample of BrC can shift the split point since it is light absorbing also @ 635nm, the typical laser wavelength used in this technique (Chen et al., 2015). We present here the results of an apportionment study of carbonaceous aerosol sources performed in a rural area and in a coastal city, both located in the North-West of Italy. The optical apportionment also provides a direct measurement of the absorption \uc5ngstr\uf6m exponent of BrC (alphaBrC) which resulted to be alphaBrC = 3.95 \ub1 0.20. Results obtained by the proposed approach are validated against independent measurements of levoglucosan and 14C concentration. We also present the last outcomes of a new approach, based on the apportionment of the absorption coefficient of particle-loaded filters, for correcting the thermo-optical analysis of PM samples (Massab\uf2 et al., 2016)

ChAMBRe \u2013 the development of an atmosferic simulation chamber for bioaerosol studies and aerosol optical properties investigation

Environmental simulation chambers are small to largescale facilities where atmospheric conditions can be monitored in real-time under control to reproduce realistic environments and to study interactions among their constituents. Up to now, they have been used mainly to study chemical and photochemical processes that occur in the atmosphere, but the high versatility of these facilities allows for a wider application covering all fields of atmospheric aerosol science. ChAMBRe (Chamber for Aerosol Modelling and Bioaerosol Research) is the stainless steel atmospheric simulation chamber (volume approximately 3 m3, see Figure 1) recently installed at the National Institute of Nuclear Physics in Genoa (INFN-Genova) in collaboration with the Environmental Physics Laboratory at the Physics Department of Genoa University (www.labfisa.ge.infn.it). The scientific activities at ChAMBRe focus on the following topics: 1) Bioaerosol properties A strong improvement in the understanding of bioaerosol behaviour can be provided by atmospheric chamber experiments, that allow for a scientific intermediate approach between \u201cin vitro\u201d and \u201cin vivo\u201d analysis. Aerosol with realistic composition, including living micro-organisms, can be injected in artificial environments with controlled physical and chemical parameters and then accurately analyzed. In particular, a systematic approach can be used for a better description of micro-organisms viability, of colonies growing modulation and other issues relevant to their spread and their pathogenicity. Very promising results in this direction were obtained by the authors at the CESAM facility at CNRS-LISA (Brotto et al. 2015), while similar results were obtained nearly at the same time at AIDA chamber at KIT (Amato et al. 2015). ChAMBRe experiments are carrying on this path to contribute in getting a deeper understanding of the still unclear mechanisms that control the evolution of bioaerosols in atmosphere and in particular of their bacterial components. 2) Aerosol optical properties \u2013 methodologies and instruments testing The instrumental development efforts at the Environmental Physics Laboratory of the University of Genoa, recently resulted in a new Multi Wavelength Absorbance Analyser (Massab\uf2 et al. 2015) which measure the light absorption on aerosol loaded filters at five wavelengths from UV (absorption bands of organic compounds, mineral dust) to near infrared (carbon soot,\u2026). Furthermore, a new data reduction methodology has been introduced to disentangle the concentration of Black and Brown carbon in atmospheric aerosol, demonstrating the need to mitigate not only exhaust but also non-exhaust emissions, as a potentially important source of PM10. The atmospheric chamber is an effective tool to produce known aerosol mixtures and to test the performance of the optical technology. Actually, there is an on-going collaboration with the CNRS-LISA team working at CESAM following that procedure that will be soon replicated at ChAMBRe facility. ChAMBRe has recently joined the Eurochamp consortium, the European atmospheric chamber facilities network. The network activities have been included in an infrastructure-oriented research project proposal that is going to be submitted within March 2016 to the H2020-INFRAIA call within EU Horizon 2020 Programme. We would like to acknowledge prof. J.F. Doussin and LISA laboratories (http://www.lisa.univ-paris12.fr/en) for providing us part of the chamber structure and for the very useful and fruitful technical discussions

The effect of Brown Carbon on thermal-optical analysis: a correction based on optical multi-wavelength analysis

Carbonaceous aerosol (CA) plays an important role in environmental issues like air quality, human health and global climate change. It mainly consists of organic carbon (OC) and elemental carbon (EC) although a minor fraction of carbonate carbon could be also present. Thermal-optical methods are presently the most widespread approach to OC/EC speciation. Despite their popularity, there is still a disagreement among the results, especially for what concerns EC as differentthermal protocols can be currently used. The main hypothesis at the basis of the technique is that on their different optical properties: while EC is strongly light absorbing, OC is generally transparent in the visible range. However, another fraction of light-absorbing carbon exists which is not black and it is generally called brown carbon (BrC) (Andreae and Gelencs\ue9r, 2006). We introduced a new way to apportion the absorption coefficient (babs) of carbonaceous atmospheric aerosols starting from a multi-wavelength optical analysis (Massab\uf2 et al., 2015). This analysis was performed thanks to the MWAA, an instrument developed at the Physics Department of University of Genoa (Massab\uf2 et al., 2013). The method uses the information gathered at five different wavelengths in a renewed and upgraded version of the approach usually referred to as Aethalometer model (Sandradewi et al., 2008). Moreover, with some assumptions, also the quantification of OC coming from fossil fuels and wood burning can be obtained. Thermal-optical methods are presently the most widespread approach to OC/EC speciation. Despite their popularity, there is still a disagreement among the results, especially for what concerns EC as different thermal protocols can be used. In fact, the pyrolysis occurring during the analysis can heavily affect OC/EC separation, depending on PM composition in addition to the used protocol. Furthermore, the presence in the sample of BrC can shift the split point since it is light absorbing also @ 635nm, the typical laser wavelength used in this technique (Chen et al., 2015). We have recently introduced a new possibility, based on the apportionment of the absorption coefficient of particleloaded filters, for correcting the thermo-optical analysis of PM samples (Massab\uf2 et al, 2016). We present here the results of an apportionment study of carbonaceous aerosol sources performed in an Alpine area, validated against independent measurements of levoglucosan. We also present developments of the thermo-optical analysis correction (Massab\uf2 et al., 2016) which lead to a better homogeneity between the results obtained with different thermal protocols

Enhancing math learning with the new digital device “MagiCal”: a pilot study

The present pilot study aims to develop and evaluate the effects of a new digital device – the calculator MagiCal – in enhancing children’s math learning. MagiCal is designed to integrate the symbolic and non-symbolic representation of numbers, as well as motor activity Twenty-nine children from second grade were randomly assigned to a training group with MagiCal or to an active control group (literacy training). Children’s math abilities (math fluency, written computation, and number comparison), math anxiety and test anxiety were measured before and after the training. Compared to the active control group, the children of the MagiCal group demonstrated a significant improvement in math fluency and written computation. However, no differences were observed in comparing numbers, math anxiety and text anxiety in the two groups.Nel presente studio pilota si è sviluppato un nuovo dispositivo digitale – la calcolatrice MagiCal – volto a promuovere l’apprendimento matematico. MagiCal integra la rappresentazione numerica simbolica e non simbolica, nonché l’esperienza motoria. Ventinove bambini frequentanti la seconda classe della Scuola primaria sono stati divisi in gruppo training con MagiCal o gruppo di controllo attivo (training sulla lettura). Prima e dopo il training, si sono misurate le abilità matematiche dei bambini (fluenza del calcolo, calcolo scritto e confronto numerico), l’ansia per la matematica e l’ansia da test. Rispetto al gruppo di controllo attivo, i bambini del gruppo training hanno dimostrato un miglioramento significativo nelle prove di fluenza del calcolo e del calcolo scritto. Non si sono osservate differenze per il confronto numerico, l’ansia per la matematica e da test

A PM10 chemically characterised nation-wide dataset for Italy. Geographical influence on urban air pollution and source apportionment

: Urban textures of the Italian cities are peculiarly shaped by the local geography generating similarities among cities placed in different regions but comparable topographical districts. This suggested the following scientific question: can such different topographies generate significant differences on the PM10 chemical composition at Italian urban sites that share similar geography despite being in different regions? To investigate whether such communalities can be found and are applicable at Country-scale, we propose here a novel methodological approach. A dataset comprising season-averages of PM10 mass concentration and chemical composition data was built, covering the decade 2005-2016 and referring to urban sites only (21 cities). Statistical analyses, estimation of missing data, identification of latent clusters and source apportionment modelling by Positive Matrix Factorization (PMF) were performed on this unique dataset. The first original result is the demonstration that a dataset with atypical time resolution can be successfully exploited as an input matrix for PMF obtaining Country-scale representative chemical profiles, whose physical consistency has been assessed by different tests of modelling performance. Secondly, this dataset can be considered a reference repository of season averages of chemical species over the Italian territory and the chemical profiles obtained by PMF for urban Italian agglomerations could contribute to emission repositories. These findings indicate that our approach is powerful, and it could be further employed with datasets typically available in the air pollution monitoring networks

Results of the first European Source Apportionment intercomparison for Receptor and Chemical Transport Models

In this study, the performance of the source apportionment model applications were evaluated by comparing the model results provided by 44 participants adopting a methodology based on performance indicators: z-scores and RMSEu, with pre-established acceptability criteria. Involving models based on completely different and independent input data, such as receptor models (RMs) and chemical transport models (CTMs), provided a unique opportunity to cross-validate them. In addition, comparing the modelled source chemical profiles, with those measured directly at the source contributed to corroborate the chemical profile of the tested model results. The most used RM was EPA- PMF5. RMs showed very good performance for the overall dataset (91% of z-scores accepted) and more difficulties are observed with SCE time series (72% of RMSEu accepted). Industry resulted the most problematic source for RMs due to the high variability among participants. Also the results obtained with CTMs were quite comparable to their ensemble reference using all models for the overall average (>92% of successful z-scores) while the comparability of the time series is more problematic (between 58% and 77% of the candidates’ RMSEu are accepted). In the CTM models a gap was observed between the sum of source contributions and the gravimetric PM10 mass likely due to PM underestimation in the base case. Interestingly, when only the tagged species CTM results were used in the reference, the differences between the two CTM approaches (brute force and tagged species) were evident. In this case the percentage of candidates passing the z-score and RMSEu tests were only 50% and 86%, respectively. CTMs showed good comparability with RMs for the overall dataset (83% of the z-scores accepted), more differences were observed when dealing with the time series of the single source categories. In this case the share of successful RMSEu was in the range 25% - 34%.JRC.C.5-Air and Climat

Comparison of PM10 concentrations and metal content in three different sites of the Venice Lagoon: An analysis of possible aerosol sources

The Venice Lagoon is exposed to atmospheric pollutants from industrial activities, thermoelectric power plants, petrochemical plants, incinerator, domestic heating, ship traffic, glass factories and vehicular emissions on the mainland. In 2005, construction began on the mobile dams (MOSE), one dam for each channel connecting the lagoon to the Adriatic Sea as a barrier against high tide. These construction works could represent an additional source of pollutants. PM10 samples were taken on random days between 2007 and 2010 at three different sites: Punta Sabbioni, Chioggia and Malamocco, located near the respective dam construction worksites. Chemical analyses of V, Cr, Fe, Co, Ni, Cu, Zn, As, Mo, Cd, Sb, Tl and Pb in PM10 samples were performed by Inductively coupled plasmaquadrupole mass spectrometry (ICP-QMS) and results were used to identify the main aerosol sources. The correlation of measured data with meteorology, and source apportionment, failed to highlight a contribution specifically associated to the emissions of the MOSE construction works. The comparison of the measurements at the three sites showed a substantial homogeneity of metal concentrations in the area. Source apportionment with principal component analysis (PCA) and positive matrix factorization (PMF) showed that a four principal factors model could describe the sources of metals in PM10. Three of them were assigned to specific sources in the area and one was characterised as a source of mixed origin (anthropogenic and crustal). A specific anthropogenic source of PM10 rich in Ni and Cr, active at the Chioggia site, was also identified

PMF5.0 vs. CMB8.2: An inter-comparison study based on the new European SPECIEUROPE database

Receptor Models are tools widely adopted in source apportionment studies. We describe here an experiment in which we integrated two different approaches, i.e. Positive Matrix Factorization (PMF) and Chemical Mass Balance (CMB) to apportion a set of PM10 (i.e. Particulate Matter with aerodynamic diameter lower than 10 \u3bcm) concentration values. The study was performed in the city of Genoa (Italy): a sampling campaign was carried out collecting daily PM10 samples for about two months in an urban background site. PM10 was collected on Quartz fiber filters by a low-volume sampler. A quite complete speciation of PM samples was obtained via Energy Dispersive-X Ray Fluorescence (ED-XRF, for elements), Ionic Chromatography (IC, for major ions and levoglucosan), thermo-optical Analysis (TOT, for organic and elemental carbon). The chemical analyses provided the input database for source apportionment by both PMF and CMB. Source profiles were directly calculated from the input data by PMF while in the CMB runs they were first calculated by averaging the profiles of similar sources collected in the European database SPECIEUROPE. Differences between the two receptor models emerged in particular with PM10 sources linked to very local processes. For this reason, PMF source profiles were adopted in refined CMB runs thus testing a new hybrid approach. Finally, PMF and the \u201ctuned\u201d CMB showed a better agreement even if some discrepancies could not completely been resolved. In this work, we compared the results coming from the last available PMF and CMB versions applied on a set of PM10 samples. Input profiles used in CMB analysis were obtained by averaging the profiles of the new European SPECIEUROPE database. The main differences between PMF and CMB results were linked to very local processes: we obtained the best solution by integrating the two different approaches with the implementation of some output PMF profiles to CMB runs

Reciprocal learning: il confronto interculturale come dispositivo per la formazione degli educatori - insights da una ricerca tra Italia e Stati Uniti

The need to foster an “intercultural stance” beginning at the ECE level is a core theme in the current debate on how to support education practitioners working in multicultural settings. Changing one’s outlook, decentring, attempting to see educational phenomena from different angles, developing alternative perspectives are required skills for quality educational work in complex and multicultural educational contexts. How can we help ECEC educators to develop an educational culture that is open to intercultural dialogue and views cultural displacement as an opportunity for learning and exercising critical-reflexive thinking? Based on data from a professional development research project with groups of educators in Italy and the United States, this article discusses how video-mediated processes of intercultural dialogue, debate and exchange can help to foster the development of an appropriate educational stance (and not just educational tools) for multicultural settings.Il tema della formazione a una “postura interculturale” fin dai servizi per la prima infanzia è al centro della riflessione contemporanea su come sostenere gli educatori impegnati in contesti educativi multiculturali. Cambiare prospettiva, decentrarsi, provare a vedere i fenomeni educativi da un altro punto di vista, vedere altrimenti sono competenze oggi necessarie per garantire la qualità del lavoro educativo in contesti educativi complessi e multiculturali. Come formare gli educatori che già lavorano nei servizi per l’infanzia a una cultura pedagogica aperta al dialogo interculturale e capace di cogliere nello spiazzamento culturale un’occasione di formazione e di allenamento al pensiero critico-riflessivo?A partire dai dati emersi da una ricerca sulla formazione degli educatori che ha coinvolto alcune educatriciin Italia e negli Stati Uniti, l’articolo propone una riflessione su come i processi di dialogo, confronto e scambio interculturale, mediati da video, possano essere dispositivi interessanti per promuovere lo sviluppo di una postura e non solo di strumenti per l’azione educativa in contesti multiculturali.O tema da formação para uma “postura intercultural” desde os serviços para a primeira infância está no centro da reflexão contemporânea em como apoiar os/as educadores/as envolvidos/as em contextos educativos multiculturais. Mudar a perspectiva, descentralizar-se, tentar entender os fenômenos educativos de um outro ponto de vista, ver de outra forma, são competências hoje necessárias para garantir a qualidade do trabalho educativo em contextos educativos complexos e multiculturais. Como formar os/as educadores/as que já trabalham nos serviços para a pequena infância para uma cultura pedagógica aberta ao diálogo intercultural e capaz de aproveitar no reposicionamento cultural uma ocasião de formação e exercícios para o pensamento crítico-reflexivo? A partir dos dados obtidos numa pesquisa acerca da formação de educadores/as que envolveu algumas educadoras da Itália e dos Estados Unidos, o artigo propõe uma reflexão a respeito de como os processos de diálogo, de confronto e troca intercultural, mediados por vídeo, podem ser dispositivos interessantes para promover o desenvolvimento de uma postura e não somente como instrumentos de ação educativa em contextos multiculturais