VIP 36: Metrics of Health Risks from Indoor Air

In a recent review of 31 green building certification schemes used around the world, IAQ was found to contribute to only 7.5% of the final score on average. As policy makers strive to reduce the energy demands of buildings by sealing or reducing outdoor air ventilation rates, an unintended consequence could be the reduction in the quality of indoor air with corresponding negative health effects at a population scale. This article summarizes the discussions of an Air Infiltration and Ventilation Centre workshop on IAQ metrics held in March 2017.

Is ventilation necessary and sufficient for acceptable indoor air quality?

The role of ventilation in achieving acceptable indoor air quality is examined in the light of emerging challenges, alternative mitigation strategies and performance indices within the spatial and time matrix of the indoor environment. By considering the source of contaminants, their nature, transportation mechanism and participation in source-sink relationships, several studies have shown that it may not be feasible nor adequate to rely on ventilation alone to attain the desired level of exposure, especially with respect to airborne aerosolised droplets with infectious potential.

Diagonal air-distribution system for operating rooms : experiment and modeling

In a test cell equipped with an operating table, a medical lamp and a manikin representing the surgeon, air velocity and tracer-gas concentration were automatically measured at more than 700 points. Numerical simulations were performed too for analyzing air quality in operating rooms. The results showed that the distribution of the contaminants depends strongly on the presence of obstacles like medical equipment and staff.

Determining ventilation strategy to defend indoor environment against contamination by integrated accessibility of contaminant source (IACS)

How to avoid or reduce the influence of suddenly released contaminant when emergency occurs ? A 3D Full scale room with displacement and mixing ventilation system is numerically studied assuming contaminant released at certain positions in the room. IACS is adopted as an index that can be applied to determine ventilation strategy with the aim of defending indoor environment against contamination.

Performance of ventilation system in a non-standard operating room

In Hong Kong, design and construction of new operating rooms and upgrading of older ones have been based on the UK Health Building Notes. In a case study, field measurements showed that the airflow and some design features did not tally with the specifed requirements.
As the risk of contamination in an operating room can be minimized through appropriate filtration and air distribution scheme, a CFD analysis was carried out with the simulation of the temperature distribution, airflow pattern and the contaminant dispersion.

Prediction of transient contaminant dispersion and ventilation performance using the concept of accessibility

The method of exposure prediction using the scales of accessibility of supplied air (ASA) and the scales of accessibility of contaminant source (ACS) is presented in this paper. The spreading performance of supplied air and indoor pollutants can be figured out by CFD simulation and then used for the prediction of contaminant dispersion. For the validation of the model, a traver gas measurement was conducted.

Critical analysis of contaminant removal efficiency assessment in a ventilated room

This study presents a critical analysis of assessment of ventilation systems effectiveness in terms of contaminant removal. For this purpose, experimental measurements are carried in a room of an experimental house called MARIA. Various ventilation scenarios are handled. The ventilated room is also equipped with a pine wood floor which emits several Volatile Organic Compounds which are considered as air pollutants here. Thereafter, based on boundary conditions given by measurements, Computational Fluid Dynamics (CFD) simulations are performed.

Comparison of biocontaminant levels associated with hard vs. carpet floors in nonproblem schools : results of a year long study

The aim of that study was to determine whether there was a quantifiable difference in biocontaminant levels between one school with a carpeted floor and another school with hard surface floor. During one year, air and floor dust samples were collected and analyzed. The results suggest that floor covering is not the major contributor to airborne levels of biocontaminants in nonproblem schools.

Development of contamination testing protocol for ventilation system components

In time, ventilation ducts and accessories get dirty and this may lead to malfunction of ventilationequipment, fire hazard and especially a decrease in supply air quality. Repeated cleaningof the components can prevent these adverse effects. The frequency of cleaning dependson how easily different components get dirty.

Impact of airflow interaction on inhaled air quality and transport of contaminants in rooms with personalized and total volume ventilation

The impact of airflow interaction on inhaled air quality and transport of contaminants betweenoccupants was studied in regard to pollution from floor covering, human bioeffluents andexhaled air, with combinations of two personalized ventilation systems (PV) with mixing anddisplacement ventilation. In total, 80 l/s of clean air supplied at 20C was distributed betweenthe ventilation systems at different combinations of personalized airflow rate. Two breathingthermal manikins were used to simulate occupants in a full-scale test room.