key: cord-0754819-dv0gm662 authors: Zhou, Yuan; Zhao, Meidan; Wang, Huan; Wang, Qi; Zhang, Kai title: The Necessity of Wearing Facemasks Correctly Especially for Students During the Epidemic date: 2021-11-26 journal: Disaster medicine and public health preparedness DOI: 10.1017/dmp.2021.345 sha: 286aa0fcc94e24830dadfd3d38b39cc2d23bbccd doc_id: 754819 cord_uid: dv0gm662 nan Ever since the outbreak of coronavirus disease 2019 (COVID-19), the public started to know more about the features of this disease. It spreads fast and has a strong infection rate. Meanwhile, it also results in massive death rates on a global scale. 1,2 COVID-19 can have person-to-person transmission through sneezing or respiratory droplets caused by cough. Its major infection routes are mouth and nose. 3 Asymptomatic people may play a crucial part in disease spread. 3 To reduce the spread of COVID-19, wearing masks and keeping proper hand hygiene are of great importance. Figure 1 shows the situation of teachers and students wearing facemasks in class in a university in China. Facemasks are a simple and powerful tool used to reduce the spread of COVID-19. One of the major concerns of the public is about the side effects. There are a variety of rumors about it, such as immune system weakness, hypercapnia, and hypoxia. People are concerned that inhaling high levels of carbon dioxide (CO 2 ) in excess of human tolerance is life-threatening because of the likelihood of CO 2 accumulation from wearing masks. However, CO 2 accumulation caused by wearing a mask does not have any scientific base. Many studies have already debunked that myth. An observational study of 20 healthy volunteers revealed mild increases in physiological responses (respiratory rate, heart rate, oxygen saturation, and so on) from wearing a surgical mask for 1 h at moderate operating frequency. However, this does not have clinical significance. 4 Only minor effects were caused by wearing masks when people are doing aerobic exercise. Additionally, surgical masks only have a mild impact on end-tidal CO 2 and seem exclusively to be engaged in strenuous exercise. Therefore, it is safe for healthy individuals to wear a face mask. 5 A study exploring new N95 masks designed for children indicated that the physiological parameters, including the end-tidal CO 2 , fractional concentration of inspired CO 2 , oxygen saturation, and pulse rate, all fell within an acceptable range when children wear a mask. Most children did not experience breathing difficulties. 6 Therefore, masks with or without micro fans were comfortable and safe for children aged 7 to14 y old when they imitated daily routine activities. 6 A recent study focusing on the influence of masks over the gas exchange in chronic obstructive pulmonary disease (COPD) patients and healthy people found that COPD patients did not show significant physiological changes in gas exchange after a 6-min walk test with a surgical mask, especially in terms of the CO 2 retention. 7 Altogether, it suggests from the current evidence that, although perceived force may be altered and breathing difficulties may increase during activity, there is only limited effect of wearing a mask on blood gas, respiration, and other physiological parameters. Such an effect is even undetectable during strenuous exercise. Moreover, most masks often do not fit the face perfectly, especially when speaking or exhaling. Compared with respiratory droplets, which carry the virus causing COVID-19, CO 2 molecules are so small that they can pass easily through cloth masks. 8 Therefore, the Centers for Disease Control and Prevention (CDC) clearly states that wearing a facemask does not raise the level of CO 2 . 8 More measures should be taken to prevent infection in the current outbreak. Wearing a facemask is considered as the first step of preventing and controlling the spread of the virus and pandemic. Health professionals should educate the public that masks are important for keeping the pandemic controlled. Students, as they have classes and are in a crowd, should be particularly careful. Author Contributions. Y.Z, M.Z., and H.W. contributed equally to this work and are co-first authors. K.Z. and Q.W. contributed to the conception and design of the work. Y.Z., K.Z., and Q.W. drafted the manuscript. M.Z. and H.W. revised the manuscript. All authors gave final approval and agreed to be accountable for all aspects of work, ensuring integrity and accuracy. Funding. The authors received no financial support for the research, authorship, and/or publication of this article. Ethical Statement. In this study, we used a photograph and we have received authorization of agreement from people in the photograph. No ethical approval was required for this manuscript as this study did not involve human subjects or laboratory animals. The important role of social media during the COVID-19 epidemic The effective prevention program at 1 hospital in China during the COVID-19 epidemic A familial cluster of pneumonia associated with the 2019 novel coronavirus indicating person-to-person transmission: a study of a family cluster Absence of consequential changes in physiological, thermal and subjective responses from wearing a surgical mask Return to training in the COVID-19 era: the physiological effects of face masks during exercise A randomised clinical trial to evaluate the safety, fit, comfort of a novel N95 mask in children Effect of face masks on gas exchange in healthy persons and patients with chronic obstructive pulmonary disease Guidance for wearing masks Figure 1 The situation of teacher and students wearing facemasks in class in a university in China