At Tokyo City University, Professor Takeshi Iwashita of the Department of Architecture, Faculty of Architecture and Urban Design and Associate Professor Hideaki Nagano of the Department of Mechanical Systems Engineering, Faculty of Science and Engineering have obtained from previous research to help prevent new coronavirus infections toward the resumption of classes. We summarized the findings on ventilation and prevention of splash diffusion in the classroom.
Professor Iwashita says that the clear relationship between "infection" and "ventilation" is unknown, but that the measured values of CO2 (carbon dioxide concentration) can give an indication of good ventilation and ventilation in each classroom, and that ventilation is thorough. I sued.
Normally, the CO2 concentration in the outdoor air is about 400 to 450 ppm, and it is often about 1 ppm or less when the windows and doors are left open and the ventilation is good (30 teacher, 800 children).Therefore, it is desirable to open windows and doors while monitoring the value of CO2 concentration.
In the future, it is expected that frequent rainfall and temperature rise will occur as the season progresses, and even if it is difficult to open the windows at all times, it is desirable to approach the outdoor CO2 concentration while making appropriate adjustments depending on the weather.
Associate Professor Nagano et al. Evaluated ventilation efficiency and droplet diffusion by fluid analysis.As a result, it was confirmed that not only sneezing and coughing, but also a lot of saliva was scattered just by speaking, and in a closed space, the droplets stayed indoors for a long time, increasing the risk of infection.In addition, as a result of genome analysis of fungi and viruses existing in the environment, it was confirmed that the fungi present on the surface of the palm move only by touching the surface of the object once.
For this reason, for places that are often touched by an unspecified number of people, such as door handles, desk surfaces, dining room ticket machines, tableware, and tables, "make sure not to touch" or "sterilize frequently". , The effectiveness of the measures shown by the Ministry of Health, Labor and Welfare, etc. was confirmed.
Tokyo City University will share this proposal not only within the university but also with schools such as affiliated schools in Setagaya Ward and Shiojiri City, Nagano Prefecture, which will lead to strengthening efforts for infection prevention.
