Throughout history, the human population has experienced major outbreaks of infectious diseases. In December 2019 the previously unknown SARS-CoV-2 virus emerged, which had a huge impact globally. Residents of long- term care facilities (LTCFs) showed to be highly susceptible to infection due to their frailty. Respiratory infectious diseases, such as COVID-19, can spread among others via the airborne transmission route. This is caused by sharing the same indoor environment. To reduce the risk of infection via the airborne route, it is important to consider ventilation and other building services system measures, including personalized ventilation (PV). PV has the potential of being a suitable solution for LTCFs, as it could still allow interaction between residents and visitors in the common rooms, which is regarded very important from a mental health perspective. To identify the potential of PV in the context of infection risk, a laboratory experiment was conducted to investigate its effectiveness on the infection risk reduction. The research was performed in a controlled climate chamber. In the experiment a person was mimicked and positioned close to a PV system that provided filtered recirculated air. A particle source maintained a constant particle concentration in the room. The performance of the PV system was measured through the particle concentration near the breathing zone as compared to the room concentration. Several design parameters were investigated. Translating the outcomes to a fictive (equivalent) ventilation rate, the Wells-Riley equation was applied to determine the infection risk. The outcomes indicated that, in this laboratory setting, the PV system can reduce the risk of an infection up to 50%. The performance is affected by the distance of the supply head to the breathing zone, the angle of the supply head, airflows in the room and the location of the particle source. To further optimize the system and allow its application in LTCFs, several aspects still need further attention, such as mobility/placing the person, the breathing pattern of the user and factors influencing the comfort and use.@en

Buildings located close to busy roads, industry or stock farms, are of risk of increased indoor particle concentrations, which negatively impacts the health of the building occupants. In order to reduce the exposure of the building occupants, it is important to take measures to reduce the concentration of particulate matter indoors. Solutions for existing buildings include application of improved filters in the air handling units, using local air cleaners and limit the use of operable windows. However, little is known about the overall effectiveness of these measures in existing buildings that are in use. The aim of our study was to quantify the effectiveness of particle reducing measures in buildings at high traffic locations. We performed a field study in a school in a neighbourhood between highways. In this school the effect of improved filters in the air handling unit, a HEPA filter at room level as well as the combination of both interventions on the particle concentrations indoors were studied. We quantified the effect of the interventions by momentary measurements of PM2,5 and ultrafine particles (≥4 nm). Moreover, PM2.5 was continuously measured outdoors and indoors. The ePM1 85% filters in the AHU seemed effective on the reduction of (ultrafine) particles (nearly 75% reduction of PM2,5). The use of a HEPA filter was not effective in our test situation.@en

Exposure to increased concentrations of particulate matter (PM2.5) is related to a higher risk of respiratory and vascular diseases. Indoors, cooking appears to be a major source of PM2.5. In dwellings it has been demonstrated that cooking can lead to concentrations well above the health limits. However, only little is known about the concentrations typically observed in professional kitchens where cooking is the major activity. Therefore, an inventory field study has been set up to measure PM2.5 exposure in the breathing zone of chefs in professional restaurants. In total seven restaurants took part in the study. In all kitchens, PM2.5 exposure in the breathing zone of the chef and at two locations in the kitchen was measured. During the measurements activities of the chef were listed and characteristics of the kitchens were mapped (e.g. open/closed kitchen, type of ventilation, type of food that is prepared). The initial results show that in all restaurants, chefs are exposed to concentrations above the WHO-limit, i.e. average daily exposure of 25 µg/m3. Cooking style, hood and background concentration in the kitchen are factors contributing to the concentration in the kitchen. However, the peak exposure of the chef appears to be highly dependent on behavior and location in relation to the stove and exhaust hoods.@en