This article explains the WELL Certification, a certification for buildings that care about health and well-being. The WELL Certification was established in 2014, and there are currently about 7,000 projects. The certification is applicable to most facility types and can be obtained by any type of ownership or use, such as building owners, building owners for rent, or tenants. The certification process proceeds in the following order: registration, document submission, and performance verification. The WELL Building Standard v2, the basis for certification, consists of ten concepts and 122 features. Certification is valid for three years. Certified companies can expect to see an increase in employee productivity, an improvement in the company's brand power, and an increase in its real estate valuation.

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Kajima is working on social and environmental issues such as SDGs company-wide, and is working to realize a “wellness space” as one of them. The Kajima Technical Research Institute Main Complex-Research building received the highest rank of WELL Building StandardTM , Platinum, in March 2021 and the WELL Healthy-Safety Rating in May 2021. Obtaining WELL certification requires work on 10 concepts and innovation items: air, water, food, light, exercise, thermal comfort, sound, materials, mind and community. In this paper, we will introduce the efforts that the facility has implemented in acquiring WELL certification, and also introduce the outline and effects of our unique　”Sotobeya“ that has acquired points in the innovation item.

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The use of sensor technology to monitor indoor air quality has made remarkable strides in the last decade. Indoor air quality monitoring has been becoming required and implemented to achieve comfort and wellness. However, the lack of data on sensor calibration, validation and device performance assessment has become a problem. In this paper, chamber experiments have been conducted to verify the accuracy of the small particle sensor. The correlation between the five small particle sensors and the conventional particle counter has been studied. As a result, measurement values obtained by all of these sensors correlated well with those obtained by conventional particle counters in a typical indoor environment. It is necessary to consider the influence of the surrounding environment and the long-term deterioration of accuracy. We continue to contribute to the improvement of indoor air quality and indoor environmental comfort by collecting data from various buildings and enhancing “air quality visualization” technology.

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COVID-19 is considered to have a risk of outbreak due to aerosol infection, and ventilation measures are important. The Ministry of Health, Labor and Welfare recommends ensuring a ventilation rate of 30m³/h per person based on the Building Sanitation Law, and world health organizations and air conditioning-related academic societies in each country have shown similar recommended standards to reduce risk of infection. In this report, the significance of setting ventilation rate per person as an infection control measure is to be analyzed based on the Wells-Riley infection probability model. Furthermore, assuming the estimated value of infectious quanta generation rates, a method for quantitatively evaluating the effect of reducing the risk of infection by combining ventilation with outside air and an air filter is presented. It is confirmed that when there is one infected occupant in the room for each use, the basic ventilation rate, which is the ventilation rate per person in the room to reduce the number of secondary cases to one or less after the event, is about 30m³/h except karaoke where extremely large quantum generation rate is assumed. In addition, while the effects of gravity sedimentation and inactivation on reducing the risk of infection are small, the effectiveness of high-performance filters has been clarified.

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