1,720,964 research outputs found
Effects of heat recovery for district heating on waste incineration health impact: a simulation study in Northern Italy
No full textThe construction of waste incinerators in populated areas always causes substantial public concern. Since the heat from waste combustion can be recovered to power district heating networks and allows for the switch-off of domestic boilers in urbanized areas, predictive models for health assessment should also take into account the potential benefits of abating an important source of diffuse emission. In this work, we simulated the dispersion of atmospheric pollutants from a waste incinerator under construction in Parma (Italy) into different environmental compartments and estimated the potential health effect of both criteria- (PM(10)) and micro-pollutants (PCDD/F, PAH, Cd, Hg). We analyzed two emission scenarios, one considering only the new incinerator, and the other accounting for the potential decrease in pollutant concentrations due to the activation of a district heating network. We estimated the effect of uncertainty in parameter estimation on health risk through Monte Carlo simulations. In addition, we analyzed the robustness of health risk to alternative assumptions on: a) the geographical origins of the potentially contaminated food, and b) the dietary habits of the exposed population. Our analysis showed that under the specific set of assumptions and emission scenarios explored in the present work: (i) the proposed waste incinerator plant appears to cause negligible harm to the resident population; (ii) despite the net increase in PM(10) mass balance, ground-level concentration of fine particulate matter may be curbed by the activation of an extensive district heating system powered through waste combustion heat recovery and the concurrent switch-off of domestic/industrial heating boilers. In addition, our study showed that the health risk caused by waste incineration emissions is sensitive to assumptions about the typical diet of the resident population, and the geographical origins of food production
A review of exposure assessment methods in epidemiological studies on incinerators
Full text linkIncineration is a common technology for waste disposal, and there is public concern for the health impact deriving from incinerators. Poor exposure assessment has been claimed as one of the main causes of inconsistency in the epidemiological literature. We reviewed 41 studies on incinerators published between 1984 and January 2013 and classified them on the basis of exposure assessment approach. Moreover, we performed a simulation study to explore how the different exposure metrics may influence the exposure levels used in epidemiological studies. 19 studies used linear distance as a measure of exposure to incinerators, 11 studies atmospheric dispersion models, and the remaining 11 studies a qualitative variable such as presence/absence of the source. All reviewed studies utilized residence as a proxy for population exposure, although residence location was evaluated with different precision (e.g., municipality, census block, or exact address). Only one study reconstructed temporal variability in exposure. Our simulation study showed a notable degree of exposure misclassification caused by the use of distance compared to dispersion modelling. We suggest that future studies (i) make full use of pollution dispersion models; (ii) localize population on a fine-scale; and (iii) explicitly account for the presence of potential environmental and socioeconomic confounding
Metodi alternativi di valutazione dell’esposizione per i residenti vicino agli inceneritori: uno studio di simulazione
No full textIntroduzione. In letteratura viene segnalata la possibile sovrastima
del rischio nel caso di misclassificazioni non differenziali
tra categorie di esposizione non adiacenti. In Emilia-Romagna
è stato realizzato un progetto sugli effetti sulla salute dell’esposizione
a inceneritori (Progetto Moniter). All’interno di
questo progetto un’indagine epidemiologica ha riguardato la
valutazione degli effetti sanitari su una coorte retrospettiva dei
residenti (periodo 1995-2006).
L’esposizione agli inceneritori su base residenziale è stata stimata
attraverso l’utilizzo di mappe da modelli di dispersione,
utilizzando i dati di emissione degli impianti al momento dell’arruolamento
(1995), assegnando a ciascun soggetto della coorte
(circa 250 000 soggetti) un valore di esposizione individuale.
Una successiva categorizzazione in quintili di questo
valore è stata utilizzata all’interno delle analisi epidemiologiche.
L’esposizione cumulativa non poteva essere calcolata per tutti
i soggetti della coorte, a causa di mancanza di completezza sulla
storia residenziale dall’inizio di attività degli impianti.
Obiettivi. Abbiamo condotto uno studio di simulazione, utilizzando
un sottocampione della coorte per il quale erano disponibili
i dati utili al calcolo dell’esposizione cumulativa, per
valutare le conseguenze di possibili errori di classificazione
derivanti dall’attribuzione dell’esposizione all’arruolamento.
Metodi. Per una sotto-coorte (circa 30 000 soggetti) erano disponibili
le informazioni sulla storia residenziale dall’inizio di
attività dell’impianto di riferimento (1980), l’esposizione cumulativa
(periodo 1980-1995) per ciascun soggetto è stata calcolata
utilizzando due differenti mappe di dispersione relative
a configurazioni differenti dell’impianto di incenerimento,etenendo
conto della mobilità residenziale nel periodo considerato.
Lo studio di validazione ha valutato la potenziale misclassificazione
dell’esposizione al momento dell’arruolamento, rispetto
all’esposizione cumulativa. Abbiamo utilizzato una procedura
di simulazione, costruendo 1 000 dataset di dati random
strutturati in modo tale da ottenere un incidence rate ratio
(IRR)=1.5 tra le classi a più alta e più bassa esposizione cumulativa
e un trend statisticamente significativo fra le 5 classi.
Risultati. Quando abbiamo confrontato le categorie di esposizione
all’arruolamento con l’esposizione cumulativa, il 73.5%
dei soggetti è rimasto nella stessa classe e il 5.2% si è spostato
in categorie non adiacenti. Le classi estreme (più bassa e più
alta) hanno mostrato una maggiore concordanza (81.7% e
84.5%). Nel complesso l’indice K di Cohen (pesato con matrice
quadratica) è risultato pari a 0.85.
Lo studio di simulazione ha calcolato gli IRR dei 1 000 dataset
utilizzando come variabile di esposizione quella calcolata all’arruolamento
nella coorte. Il valore medio dei 1 000 IRR della
categoria dei più esposti è stato pari a 1.41 [range: 1.06-2.04]
con il 29.2% delle simulazioni che hanno sovrastimato il valore
di IRR calcolato con l’esposizione cumulativa. Il trend positivo
rimane significative nel 63.9% delle simulazioni.
Conclusioni. Abbiamo trovato un’alta concordanza tra l’esposizione
all’arruolamento e quella cumulativa in una popolazione
esposta per 15 anni a inquinamento da sorgente puntiforme.
Tuttavia, in caso di errata classificazione non
differenziale tra le categorie non adiacenti, viene confermata
l’indicazione di una qualche cautela riguardo i risultati delle
analisi epidemiologiche
Combining land use regression models and fixed site monitoring to reconstruct spatiotemporal variability of NO2 concentrations over a wide geographical area
No full textThe epidemiological research benefits from an accurate characterization of both spatial and temporal variability of exposure to air pollution. This work aims at proposing a method to combine the high spatial resolution of Land Use Regression (LUR) models with the high temporal resolution of fixed site monitoring data, to model spatiotemporal variability of NO2 over a wide geographical area in Northern Italy. We developed seasonal LUR models to reconstruct the spatial distribution of a scaling factor that relates local concentrations to those measured at two reference central sites, one for the northern flat area and one for the southern mountain area. We calculated the daily average concentrations at 19 locations spread over the study areas as the product of the local scaling factor and the reference central site concentrations. We evaluated model performance comparing modeled and measured NO2 data. LUR model's R2 ranges from 0.76 to 0.92. The main predictors refers substantially to traffic, industrial land use, buildings volume and altitude a.s.l. The model's performance in reproducing measured concentrations was satisfactory. The temporal variability of concentrations was well captured: Spearman correlation between model and measures was > 0.7 for almost all sites. Model's average absolute errors were in the order of 10 μg m− 3. The model for the southern area tends to overestimate measured concentrations. Our modeling framework was able to reproduce spatiotemporal differences in NO2 concentrations. This kind of model is less data-intensive than usual regional atmospheric models and it may be very helpful to assess population exposure within studies in which individual relevant exposure occurs along periods of days or months
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
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