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Coughing is one of the most important respiratory activities for air transmitted pathogens. It is essential to understand the dispersion of exhaled particles when coughing to improve the prevention measure and reduce the cross-infection risk. However, cough flow structure is complex and influenced by many parameters. Simplifications are often made to the initial flow condition when simulating the transport of particles expelled during coughing in laboratory or numerical studies .

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.

On June 24, 2023, ASHRAE approved the publication of Standard 241-2023 Control of Infectious Aerosols. The purpose of Standard 241 is “to establish minimum requirements for control of infectious aerosols to reduce risk of disease transmission in the occupiable space” of buildings by defining “the amount of equivalent clean airflow necessary to substantially reduce the risk of disease transmission during infection risk management mode”.

Accounting for inter- and intra-personal differences requires individual and cohort comfort models. For their development, emulators for thermal sensation of occupants are needed. Physiological signals can be acquired using both wearable and contactless devices. However, due to the widespread availability of sensing methods it is difficult to select the proper measuring method for the application.

Most current environmental control systems installed in buildings aim to create a uniform IEQ, disregarding the large interpersonal and intrapersonal variability in occupants’ thermal, visual, acoustics & air quality requirements. By creating occupant micro-environments that respond to individual preferences, and relaxing the surrounding space, personalized environmental control systems (PECS) can satisfy all occupants with relatively low-energy input.

Personalized Environmental Control Systems (PECS) have advantages of controlling the localized environment at occupants’ workstation by their preference instead of conditioning an entire room. A new IEA EBC Annex (Annex 87 - Energy and Indoor Environmental Quality Performance of Personalised Environmental Control Systems) has recently started to establish design criteria and operation guidelines for PECS and to quantify their benefits. This topical session will provide an introduction to the objective/scope, activities, and intended outputs of the annex.

The development of computational fluid dynamics (CFD) made it possible to simulate the detailed flow field and temperature field within the room. The various studies numerically investigated the flow and temperature field both inside and outside the buildings. When investigating the indoor environment, human is an important factor since it perceives the indoor environment and behaves as a source of heat and contaminant as well. Some studies investigated deeper into humans by developing detailed computer-simulated persons (CSP).

This research introduces the local exhaust system (hood) into the consulting room to prevent airborne infection, especially for close-distance conversion. The hood’s capture efficiency is mainly affected by surrounding air flow, so this research compared three various underfloor air distribution systems (UFAD); floor-supply displacements ventilation (FSDV), displacement-flow-type diffuser, and swirling flow type diffuser. FSDV is a displacement ventilation method where SA comes from the whole floor through carpets or panels, forming a tranquil up-flow.

Sufficient ventilation in clinics is critical for diluting virus concentrations and lowering subsequent doses inhaled by the occupants. Several advanced simulation methods and tools for building physics and indoor air fluid dynamics are currently available in research and industry. However, in naturally ventilated buildings, indoor air distribution depends strongly on local and dynamically changing conditions, e.g., opening sizes and time, exhaust shaft location, and climatic and weather conditions.

Indoor air quality in schools is of critical importance for the health and well-being of pupils and staff. The COVID-19 pandemic highlighted the essential role that ventilation systems play in limiting the spread of airborne diseases and consumer CO2 monitors were deployed in UK classrooms as a cost-effective tool to help manage the ventilation supply. In such settings, which are occupied for long periods by the same group of people, CO2 measurements have also been used to infer the risk of far-field airborne infection.