1,721,089 research outputs found
Charged particles and cluster ions produced during cooking activities
No full textPrevious studies showed that a significant number of the particles present in indoor air are generated by cooking activities, and measured particle concentrations and exposures have been used to estimate the related human dose. The dose evaluation can be affected by the particle charge level which is usually not considered in particle deposition models. To this purpose, in this paper we show, for the very first time, the electric charge of particles generated during cooking activities and thus extending the interest on particle charging characterization to indoor micro-environments, so far essentially focused on outdoors. Particle number, together with positive and negative cluster ion concentrations, was monitored using a condensation particle counter and two air ion counters, respectively, during different cooking events. Positively-charged particle distribution fractions during gas combustion, bacon grilling, and eggplant grilling events were measured by two Scanning Mobility Particle Sizer spectrometers, used with and without a neutralizer. Finally, a Tandem Differential Mobility Analyzer was used to measure the charge specific particle distributions of bacon and eggplant grilling experiments, selecting particles of 30, 50, 80 and 100 nm in mobility diameter. The total fraction of positively-charged particles was 4.0%, 7.9%, and 5.6% for gas combustion, bacon grilling, and eggplant grilling events, respectively, then lower than other typical outdoor combustion-generated particles
A comparison of submicrometer particle dose between Australian and Italian people
No full textAlveolar and tracheobronchial-deposited submicrometer particle number and surface area data received by different age groups in Australia are shown. Activity patterns were combined with microenvironmental data through a Monte-Carlo method. Particle number distributions for the most significant microenvironments were obtained from our measurement survey data and people activity pattern data from the Australian Human Activity Pattern Survey were used.\ud
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Daily alveolar particle number (surface area) dose received by all age groups was equal to 3.0×1010 particles (4.5×102 mm2), varying slightly between males and females. In contrast to gender, the lifestyle was found to significantly affect the daily dose, with highest depositions characterizing adults. The main contribution was due to indoor microenvironments. \ud
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Finally a comparison between Italian and Australian people in terms of received particle dose was reported; it shows that different cooking styles can affect dose levels: higher doses were received by Italians, mainly due to their particular cooking activity
Variability of airborne particle metrics in an urban area
No full textIn the present study a mobile monitoring approach (i.e. bike with onboard instruments) was proposed and applied to investigate the spatial variability of all the key airborne particle metrics in an Italian urban area from a statistical point of view. Particle number, alveolar-deposited surface area, and PM<sub>10</sub> concentrations were measured through hand-held monitors and compared to simultaneous background concentrations by means of non-parametric tests and further post-hoc tests (Kruskal-Wallis test). Streets characterized by exposure levels statistically higher than the background levels for all the particle metrics were identified for different seasons in a pilot urban area (Cassino, Italy). A higher number of hot spots was detected for metrics affected by ultrafine particles (i.e. number and alveolar-deposited surface area concentrations) with respect to PM<sub>10</sub>. The effect of metrological requirements of the instrumentation on the proposed method was also discussed
Lung cancer risk of airborne particles for Italian population
No full textAirborne particles, including both ultrafine and supermicrometric particles, contain various carcinogens. Exposure and risk-assessment studies regularly use particle mass concentration as dosimetry parameter, therefore neglecting the potential impact of ultrafine particles due to their negligible mass compared to supermicrometric particles. The main purpose of this study was the characterization of lung cancer risk due to exposure to polycyclic aromatic hydrocarbons and some heavy metals associated with particle inhalation by Italian non-smoking people. A risk-assessment scheme, modified from an existing risk model, was applied to estimate the cancer risk contribution from both ultrafine and supermicrometric particles. Exposure assessment was carried out on the basis of particle number distributions measured in 25 smoke-free microenvironments in Italy. The predicted lung cancer risk was then compared to the cancer incidence rate in Italy to assess the number of lung cancer cases attributed to airborne particle inhalation, which represents one of the main causes of lung cancer, apart from smoking. Ultrafine particles are associated with a much higher risk than supermicrometric particles, and the modified risk-assessment scheme provided a more accurate estimate than the conventional scheme. Great attention has to be paid to indoor microenvironments and, in particular, to cooking and eating times, which represent the major contributors to lung cancer incidence in the Italian population. The modified risk assessment scheme can serve as a tool for assessing environmental quality, as well as setting up exposure standards for particulate matter
Personal exposure to ultrafine particles: The influence of time-activity patterns
No full textExposure to ultrafine particles (UFPs) is deemed to be a major risk affecting human health. Therefore, airborne particle studies were performed in the recent years to evaluate the most critical micro-environments, as well as identifying the main UFP sources.Nonetheless, in order to properly evaluate the UFP exposure, personal monitoring is required as the only way to relate particle exposure levels to the activities performed and micro-environments visited.To this purpose, in the present work, the results of experimental analysis aimed at showing the effect of the time-activity patterns on UFP personal exposure are reported. In particular, 24 non-smoking couples (12 during winter and summer time, respectively), comprised of a man who worked full-time and a woman who was a homemaker, were analyzed using personal particle counter and GPS monitors. Each couple was investigated for a 48-h period, during which they also filled out a diary reporting the daily activities performed. Time activity patterns, particle number concentration exposure and the related dose received by the participants, in terms of particle alveolar-deposited surface area, were measured.The average exposure to particle number concentration was higher for women during both summer and winter (Summer: women 1.8Ã104 part. cm-3; men 9.2Ã103 part. cm-3; Winter: women 2.9Ã104 part. cm-3; men 1.3Ã104 part. cm-3), which was likely due to the time spent undertaking cooking activities. Staying indoors after cooking also led to higher alveolar-deposited surface area dose for both women and men during the winter time (9.12Ã102 and 6.33Ã102mm2, respectively), when indoor ventilation was greatly reduced. The effect of cooking activities was also detected in terms of women's dose intensity (dose per unit time), being 8.6 and 6.6 in winter and summer, respectively. On the contrary, the highest dose intensity activity for men was time spent using transportation (2.8 in both winter and summer). © 2013 Elsevier B.V
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Caratterizzazione delle polveri ultrafini emesse da un impianto di incenerimento di combustibile derivato dai rifiuti (CDR)
No full textNegli ultimi anni sono stati sviluppati numerosi studi epidemiologici nell’ottica di stimare gli effetti del particolato atmosferico (PM) sulla salute umana, in particolare dal punto di vista cardiovascolare e respiratorio. Particolare attenzione è stata prestata al particolato fine (PM2.5) e ultrafine (UFPs, polveri con diametro aerodinamico equivalente inferiore a 100 nm), ma non c’è unanime consenso nella comunità scientifica su quale caratteristica e/o proprietà del particolato possa causare i maggiori danni sulla salute umana. I dati storici delle emissioni evidenziano che il principale contributo in termini di particolato fine e ultrafine è dovuto alle attività antropiche, a processi industriali e al traffico veicolare. È, quindi, rilevante caratterizzare sia le sorgenti di emissione sia l’evoluzione dimensionale del particolato al fine di determinare la distribuzione di aerosol e una valutazione dell’esposizione in un’area a elevata pressione antropica.
Negli ultimi 10-15 anni si è assistito a un rapido sviluppo tecnologico nel settore dell’incenerimento dei rifiuti, grazie anche alla specifica legislazione in alcuni paesi europei che obbliga le industrie a ridurre le emissioni tossiche derivanti dagli impianti d’incenerimento cittadini (MWIs). Di conseguenza, sono utilizzate le migliori tecnologie disponibili per il trattamento delle emissioni al camino al fine di rendere questi impianti ecologicamente sostenibili. Tuttavia, ad oggi non sono stati sviluppati né specifici apparati di abbattimento di UFPs, né condotte specifiche campagne di misura e monitoraggio presso gli impianti.
Il presente lavoro descrive la campagna sperimentale volta al monitoraggio delle UFPs condotta presso l’inceneritore di CDR di San Vittore del Lazio (FR). In particolare, sono state misurate distribuzioni dimensionali e concentrazioni totali di polveri sia in emissione sia a monte del filtro a maniche. Inoltre, è stata eseguita una caratterizzazione chimica delle UFP in termini di metalli pesanti mediante la tecnica di analisi per attivazione neutronica strumentale (INAA)
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