English

The sudden global outbreak of coronavirus diseases 2019 (COVID-19) has infected over seventy million people and resulted in over one million deaths by the end of 2020, posing a significant threat to human health. As potential carries of the novel coronavirus, exhaled airflow of infected individuals via coughs, are significant in virus transmission. This study measures human coughs' airflow velocity in a chamber filled with stage fog employing a particle image velocimetry (PIV) system.

A longitudinal study was conducted to establish metrics on perception, concentration and characterization of indoor air quality (IAQ) at a university library building. A questionnaire was applied to library staff in 2016 and 2017 to measure perceived indoor air quality (PIAQ) and perceived respiratory health impacts (PRHI). Measurements of PM2.5-10 and PM2.5 concentration levels were made in 2017 and 2019, respectively.

A major challenge in the built environment is the integration of energy and indoor environmental quality in the optimization of existing buildings. The UK’s target of net-zero energy buildings by 2050 brings in the need to optimize existing buildings for energy efficiency and to provide better indoor environmental quality (IEQ). The complications are the monitoring of the indoor environment for better indoor air quality (IAQ) and thermal comfort without compromising the energy efficiency of the building.

Respiratory infections are transmitted by droplets and droplet nuclei generated by human coughing, sneezing, and talking. Droplets and droplet nuclei come out of the mouth simultaneously with airflow, and their dispersion characteristics are important to understand the transmission route of infection. It is crucial to understand the dispersion characteristics of droplets and droplet nuclei dispersion and infection routes through numerical analysis.

The materials that compose the built environment have a key role in the resulting energy demand since their thermal properties affect the heat transfer processes. The use of cool materials aims at increasing the albedo of the urban surfaces and decreasing the heat absorbed by them. Cool materials can decrease roof temperatures, reduce energy needs for cooling and improve indoor comfort for spaces that are not air conditioned.

Ventilation in dwellings is likely to be impacted by configurations of windows and internal doors, but there is little empirical research investigating this in occupied homes. Closure of internal doors will affect noise, light, heat flow and how air moves into and through a building, as well as the volume of air in which pollutants are diluted.

Due to age-related physiological changes, older people are more vulnerable than young people to heat or cold conditions. Predicting older people's thermal sensations is essential for controlling the built environment and avoiding extreme heat/cold injuries. Previous studies mainly focused on predicting the thermal sensation of young people, and the data-driven methods are often not constrained by physiological responses. This study proposes a new integrated model to combine the two-node physiological model and the data-driven method random forest classifier.

The fan pressurization method is a common practice in many countries for measuring the air leakage of houses. The test results are sensitive to uncertainties in the measured pressures and airflows. In particular, changing wind conditions during a test result in some pressure stations having more or less uncertainty than others. Usually, it is necessary to fit the measured data to the power-law equation.

France is committed to minimizing its greenhouse gas emissions by focusing on the most energy-consuming sector, the residential and tertiary building sector. The renovation of existing buildings and the construction of energy efficient ones are therefore proposed as a possible solution. However, the concept of efficiency is ambiguous and difficult to measure and compare without common parameters and indicators. Indeed, a performance indicator is a decision support tool that describe the specific situation of something based on certain parameters.

Infiltration of unconditioned air through access openings and entrance doors with high recurrence can cause detrimental impacts to the energy performance, air quality and thermal comfort of buildings. Air curtains are of strategic importance to attenuate these negative impacts. In addition, air curtains are relevant in specialized HVAC applications for which the impediment of infiltration is also essential (e.g., reduction of smoke propagation in fire events, decrease of contamination hazard in clean rooms, preservation of refrigeration properties in cold rooms).