ventilation

Some airborne pathogens can infect susceptible people over long distances in buildings when they are transported in small respiratory particles suspended in the air. The pathogen concentration in air can be decreased using engineering controls, such as ventilation, filtration, or inactivation. To determine their effect, it is common to use the Wells-Riley model to estimate the probability that a susceptible person is infected and is a function of the dose of infectious pathogen received and a Poisson distribution.

The scientific community has been aware of the importance of indoor air quality (IAQ) for many decades, but the COVID-19 pandemic has brought a significantly higher level of attention from the general public and governmental entities to this theme. However, IAQ comprises hundreds of other parameters besides infectious pathogens, many of which can equally impact the health, comfort and well-being of occupants.

The TAIL rating scheme for assessing the quality of Thermal, Acoustic, Indoor air, Luminous, and the overall environment was initially developed to assess indoor environmental quality (IEQ) in hotels and offices. To broaden the use of the TAIL rating scheme to other buildings, its applicability for schools was studied. Two additional parameters, i.e., reverberation time and nitrogen dioxide concentration, were included to account for the specificities of the building use and population.

A Canadian provincial government has initiated a collaboration with the Indoor Air Quality (IAQ) team of the National Research Council of Canada (NRC) to conduct a controlled intervention study to determine the effectiveness of portable air cleaners (PACs) in reducing indoor air contaminants in 2 schools.

This research aims to evaluate ventilation performance on airborne transmission in buildings, by analyzing the effect of different ventilation configurations and flow rates on contaminant removal effectiveness

An approach has previously been developed to estimate space-specific carbon dioxide (CO2) levels that can serve as metrics for the adequacy of outdoor ventilation rates. These metrics are based on the CO2 concentration expected in a space given its intended or expected ventilation rate, volume, and occupant information (i.e., the number of occupants, their CO2 generation rates, and duration of occupancy).

With many existing Austrian school buildings to be renovated in the coming years, there are debates between stakeholders, about which ventilation strategy to pursue in existing schools. Therefore, different intervention strategies such as retrofitting ventilation systems, installing CO₂-monitoring signals, or raising awareness among teachers and students should be evaluated. This paper presents the preliminary results of the project “DIGIdat” on air quality measurements in the first quarter of 2023.

In France, in Residential buildings, since 1982 the ventilation regulation imposes air flow rate to be continuously extracted from every room with humidity production. A boosted level of air flow rate shall be reachable in the kitchen. Since the mid-80s demand-controlled ventilation based on humidity level in each room has been allowed, provided that the system is validated by a national commission. In practice, for 40 years every new residential building has a mechanical ventilation system and 95% of them are centralised extract only systems.

In recent years, earth-to-air heat exchanger (EAHE) systems, which is a method of pre-cooling and pre-heating outdoor air with earth-to-air heat, have been attracting attention as one of the technologies to achieve ZEB. However, at the operational phase, in order to achieve both energy saving and suppression of dew condensation control, EAHE control methods such as the timing or amount of outdoor air introduction have not been established.

The accurate estimation of the local wind pressure coefficient is crucial in the numerical modeling of natural or mixed ventilation in buildings subjected to wind. Building ventilation modeling typically relies on average wind pressure coefficient values specific to the building façade and wind direction. While the literature provides some correlations and standards for building wall-average pressure coefficients, these values are only useful in the absence of additional information or a database, as they can vary significantly based on urban forms.