![]() Many aspects of the world population’s daily life have been recently changed by the events following the SARS-COV-2 pandemic outbreak. None of the masks tested exceeded the NIOSH-recommended short-term limit in the first 15 min of use. The CO2 levels were also compared with the exposure limits recommended by NIOSH, showing that the use of N95 for 1 h exceeded the recommended 5,000 ppm for an 8-h workday. A multiple comparison method (Tukey) revealed significant differences in the levels of CO2 between all the facemask tested (p < 0.0001). The results revealed that while wearing a face mask, the ventilation conditions affected the CO2 concentration levels in the naso-buccal area of the user, especially in those that offered a higher level of protection, and in those that best fit the face of the subject. the CO2 level, a sensor based on the Non-dispersive Infrared (NDIR) principle was used. The ventilation conditions were determined by the natural ventilation of the room. Tests were performed on a healthy volunteer subject sitting at rest and breathing regularly, who used five types of face masks in well-ventilated and poorly ventilated rooms. In this work, CO2 levels were estimated in the naso-buccal area due to the use of face masks. The results of simulation and analysis showed that the current design could meet the demand of most science cases not only in infrared band but also in near infrared band and even in visible band.ĬGST was proposed by all solar observatories in Chinese Academy of Sciences, the involved universities and several overseas scientists. The spatial resolution of CGST is equivalent to an 8 meter diameter telescope, and the photon-gathering power equivalent to a 6 meter full aperture telescope. In order to achieve this science goal, CGST should be able to measure the vector magnetic field, the velocity field and the thermodynamic structure with the spatial scale of 20km (0.03 arc-second) and the temporal accuracy of sub-second, from the lower photosphere to the higher chromosphere.ĭue to the advantages of ring structure in polarization detection and thermal control, the current design of CGST (Chinese Giant Solar Telescope) is an 8 meter ring solar telescope. The prima ry science goal of CGST is, acquire the systematic knowledge of the finest magneto-hydrodynamic process in the lower solar atmosphere. Concentrations in the detected range can cause undesirable symptoms, such as fatigue, headache, and loss of concentration.Ĭhinese Giant Solar Telescope (CGST) is the next generation ground-based solar telescope which was formally listed into the National Plans of Major Science and Technology Infrastructures. According to the literature, these concentrations have no toxicological effect. No differences were observed among the three types of face masks tested. Walking at a speed of 5 km h-1, which corresponds to medium activity with breathing through the mouth, resulted in an average carbon dioxide concentration of 2875 ppm. ![]() A small increase could be observed when walking at a speed of 3 km h-1 (leisurely walking pace). Doing office work and standing still on the treadmill each resulted in carbon dioxide concentrations of around 2200 ppm. The concentrations of carbon dioxide while not wearing a face mask varied from 500 – 900 ppm. Detected carbon dioxide concentrations ranged from 2150 ± 192 to 2875 ± 323 ppm. Measurements were made using a modified indoor air quality meter equipped with a nondispersive infrared (NDIR) CO2 sensor. For the surgical mask, the concentration was determined under different conditions (office work, slow walking, and fast walking). In this study, the carbon dioxide concentration in the breathing zone was measured while wearing a surgical mask, a KN95 and a cloth mask. Lately, concern was expressed about the possibility that carbon dioxide could build up in the mask over time, causing medical issues related to the respiratory system. The use of face masks is among the measures taken to prevent person-to-person transmission of the virus (SARS-CoV-2) responsible for the coronavirus disease (COVID-19).
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