Non-linear models for black carbon exposure modelling using air pollution datasets.

Black carbon (BC) is a product of incomplete combustion, present in urban aerosols and sourcing mainly from road traffic. Epidemiological evidence reports positive associations between BC and cardiovascular and respiratory disease. Despite this, BC is currently not regulated by the EU Air Quality Directive, and as a result BC data are not available in urban areas from reference air quality monitoring networks in many countries. To fill this gap, a machine learning approach is proposed to develop a BC proxy using air pollution datasets as an input. The proposed BC proxy is based on two machine learning models, support vector regression (SVR) and random forest (RF), using observations of particle mass and number concentrations (N), gaseous pollutants and meteorological variables as the input. Experimental data were collected from a reference station in Barcelona (Spain) over a 2-year period (2018-2019). Two months of additional data were available from a second urban site in Barcelona, for model validation. BC concentrations estimated by SVR showed a high degree of correlation with the measured BC concentrations (R2 = 0.828) with a relatively low error (RMSE = 0.48 µg/m3). Model performance was dependent on seasonality and time of the day, due to the influence of new particle formation events. When validated at the second station, performance indicators decreased (R2 = 0.633; RMSE = 1.19 µg/m3) due to the lack of N data and PM2.5 and the smaller size of the dataset (2 months). New particle formation events critically impacted model performance, suggesting that its application would be optimal in environments where traffic is the main source of ultrafine particles. Due to its flexibility, it is concluded that the model can act as a BC proxy, even based on EU-regulatory air quality parameters only, to complement experimental measurements for exposure assessment in urban areas.

Determinación de la dosis eritemática mínima y reacciones anómalas a radiación ultravioleta A según fototipo / Determination of Minimal Erythema Dose and Anomalous Reactions to UVA Radiation by Skin Phototype

ANTECEDENTES: La técnica del fototest evalúa la sensibilidad de la piel a la radiación ultravioleta (RUV) mediante la determinación de la mínima dosis de radiación capaz de producir eritema (dosis mínima eritemática [DEM]) y la respuesta anómala a UVA. No existen guías protocolizadas para la técnica del fototest. METODOLOGÍA: Estudio multicéntrico de cohortes prospectivo. Un total de 232 voluntarios sanos fueron reclutados en 9 centros hospitalarios. El fototest se realizó con simuladores solares (SS) o lámparas fluorescentes de UVB de banda ancha (UVBBA). Cada sujeto recibió un total de 5 o 6 dosis progresivas de radiación eritemática y 4 dosis de UVA. La lectura se realizó a las 24 h. RESULTADOS: La DEM media por fototipo fue de 23 ± 8, 28 ± 4, 35 ± 4 y 51 ± 6 mJ/cm2 (fototipos I a IV respectivamente) para los centros que utilizaron SS y de 28 ± 5, 32 ± 3 y 34 ± 5 mJ/cm2 cuando se utilizaron lámparas de UVBBA para fototipos del II al IV. Se consideraron valores de DEM patológica 7, 19, 27 y 38 mJ/cm2, para los fototipos I al IV respectivamente cuando se emplearon SS y de 18, 24 y 24 mJ/cm2 para los fototipos II-IV expuestos a lámparas de UVBBA. A dosis de hasta 20 J/cm2 de UVA no se observaron respuestas anómalas. CONCLUSIONES: Existe homogeneidad de resultados en los diferentes centros participantes, lo que permite estandarizar el método del fotodiagnóstico para los diferentes fototipos cutáneos, así como establecer las dosis umbral que definen una respuesta anómala a la radiación ultravioleta

BACKGROUND: Phototesting is a technique that assesses the skin's sensitivity to UV radiation by determining the smallest dose of radiation capable of inducing erythema (minimal erythema dose [MED]) and anomalous responses to UV-A radiation. No phototesting protocol guidelines have been published to date. METHODOLOGY: This was a multicenter prospective cohort study in which 232 healthy volunteers were recruited at 9 hospitals. Phototests were carried out with solar simulators or fluorescent broadband UV-B lamps. Each individual received a total of 5 or 6 incremental doses of erythemal radiation and 4 doses of UV-A radiation. The results were read at 24 hours. RESULTS: At hospitals where solar simulators were used, the mean (SD) MED values were 23 (8), 28 (4), 35 (4), and 51 (6) mJ/cm2 for skin phototypes I to IV, respectively. At hospitals where broadband UV-B lamps were used, these values were 28 (5), 32 (3), and 34 (5) mJ/cm2 for phototypes II to IV, respectively. MED values lower than 7, 19, 27, and 38 mJ/cm2 obtained with solar simulators were considered to indicate a pathologic response for phototypes I to IV, respectively. MED values lower than 18, 24, and 24 mJ/cm2 obtained with broadband UV-B lamps were considered to indicate a pathologic response for phototypes II to IV, respectively. No anomalous responses were observed at UV-A radiation doses of up to 20 J/cm2. CONCLUSIONS: Results were homogeneous across centers, making it possible to standardize diagnostic phototesting for the various skin phototypes and establish threshold doses that define anomalous responses to UV radiation

Determination of minimal erythema dose and anomalous reactions to UVA radiation by skin phototype.

BACKGROUND: Phototesting is a technique that assesses the skin's sensitivity to UV radiation by determining the smallest dose of radiation capable of inducing erythema (minimal erythema dose [MED]) and anomalous responses to UV-A radiation. No phototesting protocol guidelines have been published to date. METHODOLOGY: This was a multicenter prospective cohort study in which 232 healthy volunteers were recruited at 9 hospitals. Phototests were carried out with solar simulators or fluorescent broadband UV-B lamps. Each individual received a total of 5 or 6 incremental doses of erythemal radiation and 4 doses of UV-A radiation. The results were read at 24hours. RESULTS: At hospitals where solar simulators were used, the mean (SD) MED values were 23 (8), 28 (4), 35 (4), and 51 (6) mJ/cm(2) for skin phototypes i to iv, respectively. At hospitals where broadband UV-B lamps were used, these values were 28 (5), 32 (3), and 34 (5) mJ/cm(2) for phototypes ii to iv, respectively. MED values lower than 7, 19, 27, and 38 mJ/cm(2) obtained with solar simulators were considered to indicate a pathologic response for phototypes I to IV, respectively. MED values lower than 18, 24, and 24mJ/cm(2) obtained with broadband UV-B lamps were considered to indicate a pathologic response for phototypes ii to iv, respectively. No anomalous responses were observed at UV-A radiation doses of up to 20J/cm(2). CONCLUSIONS: Results were homogeneous across centers, making it possible to standardize diagnostic phototesting for the various skin phototypes and establish threshold doses that define anomalous responses to UV radiation.

The UV Index on the Spanish Mediterranean coast.

An analysis is made of measured ultraviolet erythemal solar radiation (UVER) data recorded during the year 2003 by the networks of the Catalan Weather Service and the Environment Department of Valencia (both on the Spanish Mediterranean coast). Results show a latitudinal variation at sea level, of 3-4% per degree and an increase with altitude of 10% per km. Based on these data the UV Index has been evaluated for the measuring stations. The maximum experimental value of the UV Index was around 9 during the summer, although higher values were recorded at two stations, one at the highest elevation and the other at the lowest latitude. The annual accumulated doses of irradiation on a horizontal plane have been presented as well as the evolution through the year in units of energy, Standard Erythemal Doses and Minimum Erythemal Doses according to different phototypes. Lastly, the UV Index forecast, determined with a multiple scattering radiative transfer model, has been analyzed. Total agreement or only one unit of difference between measured and modelled values was found in 94% of cloud-free cases.

[Community-acquired pneumonia referred for hospital management. Its epidemiology and the diagnostic and therapeutic approaches]. / Neumonía adquirida en la comunidad remitida al medio hospitalario. Epidemiología y actitud diagnóstica y terapéutica.

OBJECTIVES: To determine the epidemiology of community-acquired pneumonia referred to the hospital and to characterize the diagnostic and therapeutic approach adopted by physicians. METHOD: Retrospective epidemiological and descriptive clinical study based on case histories consistent with a diagnosis of community-acquired pneumonia (Fang et al. Medicine, 1990; 69:307-16) of patients referred to hospitals in Soria (Spain) over a period of one year. The patients were grouped by severity and the presence of risk factors for unusual etiology. Initial approaches were compared to those advocated by various sources. RESULTS: Three hundred eight cases of community-acquired pneumonia were diagnosed, and 82% of the patients were admitted. Mean age was 68 +/- 26 years (43% over 80 years of age). Men accounted for 56%. Two hundred seventeen patients (70%) were classified as seriously ill, 203 (66%) had risk factors for unusual etiology, and 166 (54%) were classified in both categories. Mortality among admitted patients was 13%. Etiological diagnoses did not correspond to the guidelines of the Spanish Society of Pneumology and Chest Surgery (SEPAR), with microbial identification achieved in 5%. Empirical treatment followed SEPAR guidelines in 45% of the cases. The Mensa guidelines were followed in 23% and the Sanford guidelines in 20%. CONCLUSIONS: The incidence of community-acquired pneumonia in this population is 3.2 cases per 1,000 inhabitants/year. The population is mainly elderly and comorbidity is common, although mortality is low. We believe common criteria should be adopted for managing community-acquired pneumonia and that empirical treatment should be directed toward germs identified in each setting, based on appropriate etiological investigation.