Tecnologie sostenibili per il social housing

“Tecnologie sostenibili per il social housing”: la mia tesi affronta il tema dell’edilizia sociale cercando di capire se può ancora diventare un campo di ricerca e sperimentazione architettonica come lo è stato in più occasioni nell’ultimo secolo. La ricerca si è sviluppata in due fasi: una prima attività di studio della vicenda storica dell’abitazione sociale in Italia, con alcuni confronti europei, fino ad analizzare il nuovo quadro che si è andato delineando dalla fine degli anni ’90 e che caratterizza la situazione attuale. Successivamente, la progettazione di un piccolo intervento di edilizia abitativa che si propone di rispondere agli attuali profili della domanda, puntando a scelte tipologiche e costruttive coerenti. Nel trentennio 1950-’80, nell’Europa uscita dalla Seconda guerra mondiale, e in Italia in particolare, l’edilizia popolare ha vissuto un periodo dinamico, ricco di interventi normativi da parte dello Stato, (su tutte la legge Fanfani, e le norme Gescal) che hanno permesso di realizzare molti degli edifici ancora oggi utilizzati, accelerando la ripresa economica e sociale. Dopo gli anni ’80, le ricerche e le sperimentazioni in campo architettonico si spostano verso altri temi; superata la necessità di fornire una casa a milioni di persone, il tema dell’alloggio sembra perdere il forte rilievo sociale che aveva avuto nei decenni precedenti. Fino a ritenere che il tema dell’alloggio e in particolare dell’alloggio sociale, non avesse più la necessità di essere sperimentato e approfondito. Oggi la situazione riguardante la sperimentazione non è molto diversa: sono ancora molto limitati, infatti, gli studi e le ricerche sul tema dell’alloggio sociale. Ciò che è nuovamente mutata, invece, è l’emergenza di una nuova domanda di casa e la drammatica esigenza sociale di fornire un alloggio a milioni di famiglie che non se lo possono permettere. Le dinamiche che guidano questa nuova ondata di richiesta di alloggi sono molteplici, sia di natura sociale che economica. Sul piano sociale: - l’aumento del numero delle famiglie, passate da 22.226.000 nel 200o a 24.642.000 nel 2010, con un aumento del 9,8% in un solo decennio; - la “nuclearizzazione” delle famiglie e la loro contrazione dimensionale, fino agli attuali 2,4 componenti per nucleo; - l’invecchiamento della popolazione; - l’aumento della popolazione straniera, con oltre 3.900.000 di immigrati regolari. Su quello economico: - l’aumento della povertà assoluta: in Italia 1.162.000 famiglie (4,7%) corrispondenti a 3.074.000 individui vivono sotto la soglia di povertà; - l’aumento della povertà relativa, che investe oggi 2.657.000 famiglie (9,3%) e l’aumento delle famiglie a rischio di povertà (920.000 famiglie, pari al 3,7% dei nuclei). Questi dati evidenziano la dimensione del problema abitativo e smentiscono l’opinione che si tratti di una questione marginale: nel 2010 in Italia almeno 1.162.000 non hanno le risorse per pagare un affitto, nemmeno a canone agevolato, e 4.739.000 famiglie non riescono a pagare un affitto ai prezzi del libero mercato, ma non hanno la possibilità di entrare nelle graduatorie per l’assegnazione di un alloggio sociale. Da questa panoramica sulle dimensioni del disagio abitativo, prende spunto la progettazione del mio sistema costruttivo, che si pone come obiettivo quello di ridurre i costi di costruzione tramite la standardizzazione dei componenti, consentendo di conseguenza, un minor costo di costruzione e quindi la possibilità di canoni di affitto ridotti, mantenendo buoni standard di qualità degli alloggi, sostenibilità ambientale e risparmio energetico. Le linee guida che hanno portato alla progettazione del sistema sono: - modularità degli spazi abitativi - zonizzazione funzionale - razionalizzazione impiantistica - illuminazione naturale - industrializzazione dei sistema costruttivo - standardizzazione dei componenti. Il risultato è un catalogo di alloggi di diverse metrature, aggregabili secondo tre tipologie residenziali. - a ballatoio - in linea - a torre Messo a punto questo sistema costruttivo, è stato progettato un intervento in un contesto specifico, per verificare l’applicabilità delle soluzioni sviluppate ed esplorarne alcune possibilità

Two-wavelength thermo-optical determination of Organic, Elemental and Brown Carbon.

Introduction Thermo-optical analysis (TOA) is widely adopted for the quantitative determination of Carbonaceous Aerosol in aerosol samples collected on quartz fibre filters. Nevertheless, the quantification of Elemental and Organic Carbon (EC and OC) presents several issues, as the well-known artefacts induced by the formation of pyrolytic carbon (Pyr-C) during the analysis. Furthermore, it is usually neglected the uncertainty due to the possible presence of Brown Carbon (BrC) i.e. the optically active fraction of OC produced by biomass burning and with thermic characteristics intermediate between OC and EC. Methods In (Massab\uf2 et al., 2019), a modified Sunset EC/OC Analyzer was introduced. Briefly, the unit was upgraded making possible the alternative use of a laser diode at \u3bb = 635 nm and at \u3bb = 405 nm. In this way, the optical transmittance through the sample can be monitored at both the wavelengths. Both BrC and Pyr-C absorbance increases at shorter wavelength, so the new set-up has a better sensitivity to these species. First results Massab\uf2 et al., 2019) suggested that the 2-lambda TOA could reduce the discrepancy usually observed between EC/OC quantification by the NIOSH and EUSAAR protocols (Cavalli et al., 2010). Adopting the methodology described in (Massab\uf2 et al., 2016), i.e. the coupled use of the Multi-Wavelength Absorbance Analyzer (MWAA) and of the Sunset EC/OC Analyzer, we therefore performed a new experiment based on a set of samples collected in a rural site. Half of the samples were analysed with the EUSAAR_2 and NIOSH protocols at both the wavelengths looking for OC, EC and BrC concentration values. The other sub-set was instead used to compare the TOA results on untreated and water-washed samples, again using both the laser diodes at \u3bb = 635 nm and \u3bb = 405 nm. The water-wash step removes the water-soluble compounds, which are expected to be the main responsible of the Pyr-C formation in TOA (Piazzalunga P. et al., 2011). Finally, all the samples were also analysed to quantify the Levoglucosan (1,6-Anhydro-betaglucopyranose) content. This step, performed by High Performance Anion Exchange Chromatography coupled with Pulsed Amperometric Detection(HPLC-PAD, more details in Piazzalunga A. et al., 2010), provided the quantification of this biomass burning tracer regardless of BrC thermo-optical properties. The BrC Mass Absorption Cross-section (MAC) at \u3bb = 405 nm and \u3bb = 635 nm was finally determined. Conclusions The data reduction of the described experiment is still in progress: the results will be presented and discussed at the Conference. This work has been partially financed by the National Institute of Nuclear Physics (INFN) in the frame of the TRACCIA experiments. Cavalli, F., Putaud, J. P., Viana, M., Yttri, K. E., & Gemberg, J. (2010). Toward a standardized thermal-optical protocol for measuring atmospheric Organic and Elemental Carbon: the EUSAAR protocol. Atmos. Meas. Tech., 3, 79-89. Massab\uf2, D., Altomari, A., Vernocchi, V., & Prati, P. (2019). Two-wavelength thermo-optical determination of Light Absorbing Carbon in atmospheric aerosols. Atmos. Meas. Tech. Discuss. Massab\uf2, D., Caponi, L., Bove, M. C., & Prati, P. (2016). Brown carbon and thermal-optical analysis: a correction based on optical multiwavelength apportionment of atmospheric aerosols. Atmos. Environ., 125, 119-125. Piazzalunga, A., Fermo, P., Bernardoni, V., Vecchi, R., Valli, G., & De Gregorio M. A. (2010). A simplified method for levoglucosan quantification in wintertime atmospheric particulate matter by high performance anion-exchange chromatography coupled with pulsed amperometric detection. Int. J. Environ. An. Ch., 90, 934-947. Piazzalunga, P., Bernardoni, V., Fermo, P., Valli, G., & Vecchi, R. (2011). On the effect of watersoluble compounds removal on EC quantification by TOT analysis in urban aerosol samples. Atmos. Chem. Phys., 11, 10193-10203

Two-wavelength thermo-optical determination of Light Absorbing Carbon in atmospheric aerosols

Thermo-optical analysis is widely adopted for the quantitative determination of Total, TC, Organic, OC, and Elemental, EC, Carbon in atmospheric aerosol sampled by suitable filters. Nevertheless, the methodology suffers of several uncertainties and artefacts as the well-known issue of charring affecting the OC-EC separation. In the standard approach, the effect of the possible presence of Brown Carbon, BrC, in the sample is neglected. BrC is a fraction of OC, usually produced by biomass burning with a thermic behaviour intermediate between OC and EC. BrC is optically active: it shows an increasing absorbance when the wavelength moves to the blue/UV region of the electromagnetic spectrum. Definitively, the thermo-optical characterization of carbonaceous aerosol should be reconsidered to address the possible BrC content in the sample under analysis. We introduce here a modified Sunset Lab Inc. EC/OC Analyzer. Starting from a standard commercial set-up, the unit has been modified at the Physics Department of the University of Genoa (IT), making possible the alternative use of the standard laser diode at \u3bb = 635 nm and of a new laser diode at \u3bb = 405 nm. In this way, the optical transmittance through the sample can be monitored at both the wavelengths. Since at shorter wavelengths the BrC absorbance is higher, a better sensitivity to this species is gained. The modified set-up also gives the possibility to quantify the BrC concentration in the sample at both the wavelengths. The new unit has been thoroughly tested, with both artificial and real-world samples: the first experiment, in conjunction with the Multi Wavelength Absorbance Analyzer (MWAA, Massab\uf2 et al., 2013 and 2015), resulted in the first direct determination of the BrC Mass Absorption Coefficient (MAC) at \u3bb = 405 nm: MAC = 23 \ub1 1 m2 g-1

A New PM Sampler with a Built-In Black Carbon Continuous Monitor

open6We introduce a new instrument for sampling the airborne particulate matter (PM) while monitoring the black carbon (BC) atmospheric concentration. The concentration of PM and BC are usually measured by separate instruments with possible systematics differences even in the collecting inlets. The new equipment is based on a low-volume sequential PM sampler, fully compliant with the EU-CEN and US-EPA regulatory standards, with a built-in optical BC monitor. The BC concentration is continuously measured during the sampling in the PM accumulated on the filter while the PM concentration can be obtained off-line by a standard gravimetric analysis. The optical set-up, upstream the collecting filter, is composed by a single wavelength light source (λ = 635 nm) and a photodiode, placed in way to receive the light backscattered by the filter surface at a fixed angle. The mechanical arrangement does not introduce any perturbation to the PM sampling. Thanks to an original calibration curve, the sample absorbance is deduced from the output signal of the photodiode. Finally, the BC concentration is obtained through the Mass Absorption Coefficient (MAC). After the sampling and the PM gravimetric determination, the same filter can be sent to other compositional analyses. Thermo-optical quantification of the Elemental and Organic Carbon (EC and OC) in the filter sample can thus be exploited to tune the MAC value to the PM composition of a particular site. The main features of the new instrument and the set of validation tests against other PM samplers and BC monitors of widespread use (i.e.,: Multi Angle Absorption Photometer and aethalometer) are detailed and discussedopenLorenzo Caponi,Gianluca Cazzuli,Giulio Gargioni,Dario Massabò,Paolo Brotto, Paolo PratiCaponi, Lorenzo; Cazzuli, Gianluca; Gargioni, Giulio; Massabo', Dario; Brotto, Paolo; Prati, Paol

HyFlex EDM rotary Ni-Ti prototypes: the effect of an innovative machining technology on Ni-Ti wear

Aim. HyFlex EDM files were recently introduced pre- senting an innovative electro discharge machining (EDM) process of fabrication. The aim of this study was to evalua- te the surface and microstructural alterations of new and in vitro used HyFlex EDM Ni-Ti rotary prototypes. Methods. The surface and microstructural characteristi- cs of 15 new HyFlex EDM instruments were analyzed by ESEM equipped with energy dispersive x-ray spectropho- tometry (EDS) and optical metallographic imaging. Instru- ments were subjected to instrumentation tests on severely curved root canals (ranging between 50° and 70°) of ex- tracted multi-rooted teeth. Once that canal patency was verified with a #10 K-file, the working length was determi- ned by subtracting 1mm. HyFlex EDM files were used with a 16:1 reduction handpiece X-Smart (Dentsply Maillefer, Baillagues, Switzerland) following the manufacture’s direc- tion, at 500 rpm and 2.5Ncm, with slightly apical pressure and pecking motion. The operative sequence was: 25/12 at 2/3 of the WL, 10/05 and 25/08 at WL. Irrigation was per- formed at every change of instrument, with a total amount of3mlof5%NaOCland3mlof10%EDTA(Ogna,Mug- giò, Italy). Each instrument was used in 10 curved canals, washed in an ultrasonic bath containing detergent for 10 min and then autoclaved at 134°C. Surface and microstruc- tural characterizations were repeated on used instruments at same points and with same angulations to compare the pre- and postoperative micrographs, in order to verify the appearance of fractures, unwinding, microcracks, blade di- sruption and tip deformation. Results. Surface and microstructural characteriza- tion of new instruments revealed the typical features of a NiTi ED-Machined alloy with an irregular and “craters-like” surface. High magnification microgra- phs disclosed a non-uniform structure were pits, po- res and voids caused the peculiar aspect of a “rough- spark-machined” surface. No fractures were registered during instrumentation of curved canals. Surface and microstructural characterization of used files revealed no wear and no degradation of the 25.12 and 25.08 files. The tip segment was confirmed as the most me- chanically stressed portion of 10.05 prototypes. All the instruments, after several uses, well-preserved the “craters-like” irregular surface without cutting edge al- terations. The metallographic inspection on the cross section of brand new HyFlex EDM files showed an homogeneous martensitic phase. The microstructure appeared uniform from the surface to the bulk, and no microcracks or defect were identified, even at high optical magnification (1000X). Conclusion. Unaltered spark-machined surface and low microstructural degradation are the main features of recently introduced HyFlex EDM. Caution would be re- commended regarding reuse of small HyFlex EDM files. Instruments exhibited a safe in vitro use in presence of severely curved canals

Irony Detection in Twitter with Imbalanced Class Distributions

[EN] Irony detection is a not trivial problem and can help to improve natural language processing tasks as sentiment analysis. When dealing with social media data in real scenarios, an important issue to address is data skew, i.e. the imbalance between available ironic and non-ironic samples available. In this work, the main objective is to address irony detection in Twitter considering various degrees of imbalanced distribution between classes. We rely on the emotIDM irony detection model. We evaluated it against both benchmark corpora and skewed Twitter datasets collected to simulate a realistic distribution of ironic tweets. We carry out a set of classification experiments aimed to determine the impact of class imbalance on detecting irony, and we evaluate the performance of irony detection when different scenarios are considered. We experiment with a set of classifiers applying class imbalance techniques to compensate class distribution. Our results indicate that by using such techniques, it is possible to improve the performance of irony detection in imbalanced class scenarios.The first author was funded by CONACYT project FC-2016/2410. Ronaldo Prati was supported by the São Paulo State (Brazil) research council FAPESP under project 2015/20606-6. Francisco Herrera was partially supported by the Spanish National Research Project TIN2017-89517-P. The work of Paolo Rosso was partially supported by the Spanish MICINN under the research project MISMIS (PGC2018-096212- B-C31) and by the Generalitat Valenciana under the grant PROMETEO/2019/121.Hernandez-Farias, DI.; Prati, R.; Herrera, F.; Rosso, P. (2020). Irony Detection in Twitter with Imbalanced Class Distributions. Journal of Intelligent & Fuzzy Systems. 39(2):2147-2163. https://doi.org/10.3233/JIFS-179880S21472163392Batista, G. E. A. P. A., Prati, R. C., & Monard, M. C. (2004). A study of the behavior of several methods for balancing machine learning training data. ACM SIGKDD Explorations Newsletter, 6(1), 20-29. doi:10.1145/1007730.1007735Chawla, N. V., Bowyer, K. W., Hall, L. O., & Kegelmeyer, W. P. (2002). SMOTE: Synthetic Minority Over-sampling Technique. Journal of Artificial Intelligence Research, 16, 321-357. doi:10.1613/jair.953Fernández A. , García S. , Galar M. , Prati R.C. , Krawczyk B. and Herrera F. , Learning from imbalanced data sets, Springer, (2018).Haibo He, & Garcia, E. A. (2009). Learning from Imbalanced Data. IEEE Transactions on Knowledge and Data Engineering, 21(9), 1263-1284. doi:10.1109/tkde.2008.239Farías, D. I. H., Patti, V., & Rosso, P. (2016). Irony Detection in Twitter. ACM Transactions on Internet Technology, 16(3), 1-24. doi:10.1145/2930663Japkowicz, N., & Stephen, S. (2002). The class imbalance problem: A systematic study1. Intelligent Data Analysis, 6(5), 429-449. doi:10.3233/ida-2002-6504Kumon-Nakamura, S., Glucksberg, S., & Brown, M. (1995). How about another piece of pie: The allusional pretense theory of discourse irony. Journal of Experimental Psychology: General, 124(1), 3-21. doi:10.1037/0096-3445.124.1.3López, V., Fernández, A., García, S., Palade, V., & Herrera, F. (2013). An insight into classification with imbalanced data: Empirical results and current trends on using data intrinsic characteristics. Information Sciences, 250, 113-141. doi:10.1016/j.ins.2013.07.007Mohammad, S. M., & Turney, P. D. (2012). CROWDSOURCING A WORD-EMOTION ASSOCIATION LEXICON. Computational Intelligence, 29(3), 436-465. doi:10.1111/j.1467-8640.2012.00460.xMohammad, S. M., Zhu, X., Kiritchenko, S., & Martin, J. (2015). Sentiment, emotion, purpose, and style in electoral tweets. Information Processing & Management, 51(4), 480-499. doi:10.1016/j.ipm.2014.09.003Poria, S., Gelbukh, A., Hussain, A., Howard, N., Das, D., & Bandyopadhyay, S. (2013). Enhanced SenticNet with Affective Labels for Concept-Based Opinion Mining. IEEE Intelligent Systems, 28(2), 31-38. doi:10.1109/mis.2013.4Prati, R. C., Batista, G. E. A. P. A., & Silva, D. F. (2014). Class imbalance revisited: a new experimental setup to assess the performance of treatment methods. Knowledge and Information Systems, 45(1), 247-270. doi:10.1007/s10115-014-0794-3Reyes, A., Rosso, P., & Veale, T. (2012). A multidimensional approach for detecting irony in Twitter. Language Resources and Evaluation, 47(1), 239-268. doi:10.1007/s10579-012-9196-xSulis, E., Irazú Hernández Farías, D., Rosso, P., Patti, V., & Ruffo, G. (2016). Figurative messages and affect in Twitter: Differences between #irony, #sarcasm and #not. Knowledge-Based Systems, 108, 132-143. doi:10.1016/j.knosys.2016.05.035Utsumi, A. (2000). Verbal irony as implicit display of ironic environment: Distinguishing ironic utterances from nonirony. Journal of Pragmatics, 32(12), 1777-1806. doi:10.1016/s0378-2166(99)00116-2Whissell, C. (2009). Using the Revised Dictionary of Affect in Language to Quantify the Emotional Undertones of Samples of Natural Language. Psychological Reports, 105(2), 509-521. doi:10.2466/pr0.105.2.509-521Wilson, D., & Sperber, D. (1992). On verbal irony. Lingua, 87(1-2), 53-76. doi:10.1016/0024-3841(92)90025-

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

Characterization of soot produced by the mini inverted soot generator with an atmospheric simulation chamber

The performance of a mini inverted soot generator (MISG) has been investigated at ChAMBRe (Chamber for Aerosol Modelling and Bio-aerosol Research) by studying the properties of soot particles generated by ethylene and propane combustion. This work deepens and expands the existing characterization of the MISG, which also exploits an atmospheric simulation chamber (ASC). Different from previous works, MISG performance has been also tested at different fuel flows and higher global equivalence ratios. MISG exhausts were investigated after their injection inside the atmospheric simulation chamber, which is another novelty of this work. Starting from an extensive classification of combustion conditions and resulting flame shapes, the MISG exhaust was characterized in terms of concentration of emitted particles and gases, particle size distribution, and optical properties. Soot particles were also collected on quartz fibre filters and then analysed by optical and thermal\u2013optical techniques to measure the spectral dependence of the absorption coefficient babs and their composition in terms of elemental carbon and organic carbon (EC and OC). Significant differences could be observed when the MISG was fuelled with ethylene and propane in terms of particle size. In particular, the production of super-micrometric aggregates was observed for ethylene combustion. With equal combustion conditions, ethylene produced a higher number concentration of particles and smaller mode diameters. Soot particles produced by propane combustion resulted in higher EC : TC (total carbon) ratios and they were more light absorbing than particles generated by ethylene combustion. Values of the mass absorption cross section (MAC) and of the \uc5ngstr\uf6m absorption exponent (AAE) turned out to be compatible with the literature, even if there were some specific differences. The comprehensive characterization of the MISG soot particles is an important piece of information to design and perform experiments in atmospheric simulation chambers. Particles with well-known properties can be used, for example, to investigate the possible interactions between soot and other atmospheric pollutants, the effects of meteorological variables on soot properties, and the oxidative and toxicological potential of soot particles