Assessment of variations in air quality in cities of Ecuador in relation to the lockdown due to the COVID-19 pandemic

CFD simulation study and experimental analysis of indoor air stratification in an unventilated classroom: A case study in Spain

Health problems and respiratory diseases are associated with poor indoor air ventilation. We investigated the air quality inside a classroom-laboratory where no ventilation is provided. The case of study, consisting of an internal enclosure, is located at the Escuela Técnica Superior de Edificación (ETSEM) of Madrid (Spain). The high height favours air stratification which is analysed in terms of temperature and CO2 spatial distribution. Temperature, air humidity, atmospheric pressure and CO2 concentration measurements were taken in time at three different height locations. A CFD numerical model was established to analyse air quality. Flow circulation is derived by solving full 3D Navier - Stokes governing equations, coupled with the thermal problem. The diffusion problem of the CO2 produced by the inner occupants is then derived from the kinematics solution. Three scenarios were taken into account: occupants seated (1), standing (2), half seated, half standing (3). Results clearly show the air stratification as a result of density gradient, which is in turn determined by temperature difference between the occupants and the surrounding air. Temperature prediction maximum relative error is contained to 3.5 %. As expected, CO2 concentration increases over time, reaching maximum values depending on the configuration considered and height location.

Design of an innovative sanitation system for bike-sharing service

The concept of a novel sanitization device specifically designed for helmets used in bike share services is presented in this scientific work. The system uses ozone, a powerful oxidizing agent, to completely remove dust and bacteria from the helmet surface. Throughout the development process, special attention has been paid to the dual initial goals of efficacy in removing dirt and batteries, as well as ease of use related to the device's safety. In fact, today's sharing services are rarely capable of providing adequate disinfection of the tools, which is especially troubling given the most recent years of pandemic caused by Covid-19. The invention of the ozone-based sanitization device addresses the growing concern about hygiene and safety in bike share services. Furthermore, due to its portability and ease of use, the device is a cost-effective and viable solution for use in a variety of settings. A significant contribution to the advancement of sanitization technology and public health is expected with this work.