Application of levitation-jet synthesized nickel-based nanoparticles for gas sensing

The gas sensing properties of nickel ferrite (NiFe2O4) and nickel oxide (NiO) nanoparticles prepared by a levitation-jet synthesis (LJS) method are reported. These have been compared to the gas sensing properties of a NiO sensor, prepared using a commercially-sourced powder. The microstructure, surface area, particle size and morphology varied widely across the sensors fabricated. Gases included ethanol, acetone, carbon monoxide, toluene and nitrogen dioxide and the gas response of the sensors was investigated at different operating temperatures. The NiFe2O4 sensor presented most promise as a gas sensor, with outstanding sensor sensitivity towards ppb concentrations of NO2. This sensor was also remarkably sensitive to ethanol and, to a greater or lesser degree, towards acetone and toluene gases. In general, sensors were poorly responsive to the carbon monoxide concentrations tested. This study is one of the first reports of using LJS-based powders for gas sensing applications for the detection of environmentally-relevant gases

Indoor air pollution, physical and comfort parameters related to schoolchildren's health:Data from the European SINPHONIE study

Substantial knowledge is available on the association of the indoor school environment and its effect among schoolchildren. In the same context, the SINPHONIE (School indoor pollution and health: Observatory network in Europe) conducted a study to collect data and determine the distribution of several indoor air pollutants (IAPs), physical and thermal parameters and their association with eye, skin, upper-, lower respiratory and systemic disorder symptoms during the previous three months. Finally, data from 115 schools in 54 European cities from 23 countries was collected and included 5175 schoolchildren using a harmonized and standardized protocol. The association between exposures and the health outcomes were examined using logistic regression models on individual indoor air pollutants (IAPs); a VOC (volatile organic compound) score defined as the sum of the number of pollutants to which the children were highly exposed (concentration > median of the distribution) in classroom was also introduced to evaluate the multiexposure \u2013 outcome association, while adjusting for several confounding factors. Schoolchildren exposed to above or equal median concentration of PM2.5, benzene, limonene, ozone and radon were at significantly higher odds of suffering from upper, lower airways, eye and systemic disorders. Increased odds were also observed for any symptom (sick school syndrome) among schoolchildren exposed to concentrations of limonene and ozone above median values. Furthermore, the risks for upper and lower airways and systemic disorders significantly increased with the VOCs score. Results also showed that increased ventilation rate was significantly associated with decreased odds of suffering from eye, skin disorders whereas similar association was observed between temperature and upper airways symptoms. The present study provides evidence that exposure to IAPs in schools is associated with allergic and respiratory symptoms in children. Further investigations are needed to confirm our findings