Here are key anchor points to the extensive scientific literature that explores the environmental impact of masks and the health effects of masks, establishing that wearing surgical masks and respirators (e.g., 'N95') does not significantly reduce the risk of contracting a verified illness:
Jacobs, J. L. et al. (2009) explored the 'Use of surgical face masks to reduce the incidence of the common cold among health care workers in Japan: A randomized controlled trial,' published in the American Journal of Infection Control, Volume 37, Issue 5, 417 – 419. The study found that N95-masked health care workers (HCW) were significantly more likely to experience headaches, and face mask use was not shown to provide benefits in terms of cold symptoms or the incidence of colds.
Cowling, B. et al. (2010) conducted a 'Face masks to prevent transmission of influenza virus: A systematic review,' published in Epidemiology and Infection, 138(4), 449-456. This review revealed that none of the studies showed a benefit from wearing a mask, whether in HCW or community members in households.
Bin-Reza et al. (2012) presented findings in 'The use of masks and respirators to prevent transmission of influenza: a systematic review of the scientific evidence,' in Influenza and Other Respiratory Viruses 6(4), 257–267. They noted, 'There were 17 eligible studies... None of the studies established a conclusive relationship between mask/respirator use and protection against influenza infection.'
Smith, J.D. et al. (2016) analyzed 'Effectiveness of N95 respirators versus surgical masks in protecting health care workers from acute respiratory infection: a systematic review and meta-analysis,' published in CMAJ. They identified six clinical studies and determined that there was no significant difference between N95 respirators and surgical masks in associated risks of laboratory-confirmed respiratory infection, influenza-like illness, or reported workplace absenteeism.
Offeddu, V. et al. (2017) discussed 'Effectiveness of Masks and Respirators Against Respiratory Infections in Healthcare Workers: A Systematic Review and Meta-Analysis,' in Clinical Infectious Diseases, Volume 65, Issue 11. Their findings suggested that self-reported assessments of clinical outcomes were prone to bias, and evidence of a protective effect of masks or respirators against verified respiratory infection (VRI) was not statistically significant.
Radonovich, L.J. et al. (2019) conducted a randomized clinical trial titled 'N95 Respirators vs Medical Masks for Preventing Influenza Among Health Care Personnel,' published in JAMA. They concluded that among 2862 randomized participants, there was no significant difference in the incidence of laboratory-confirmed influenza between N95 respirators and medical masks.
Long, Y. et al. (2020) reviewed 'Effectiveness of N95 respirators versus surgical masks against influenza: A systematic review and meta-analysis,' in J Evid Based Med. Their meta-analysis of six RCTs involving 9,171 participants indicated no statistically significant differences in preventing laboratory-confirmed influenza or respiratory infections between N95 respirators and surgical masks. It was noted that while N95 respirators showed some protective effect against bacterial colonization, they were not associated with a lower risk of laboratory-confirmed influenza.
Furthermore, the health effects of masks have raised concerns regarding carbon dioxide levels and overall respiratory health. Various studies and articles discuss these implications, indicating that mask mandates may not only be ineffective but could also pose risks to individual health and the environment. For more insights, you can explore sources discussing the effects of masks on carbon dioxide levels and the potential for pulmonary toxicity in schools and daycares.