RESUMO
Mask wearing can protect health care workers. However, its efficacy in avoiding the health effects of air pollution is not well studied. Recently, we evaluated the relationship between air pollution and health status or peak expiratory flow rate (PEFR). At the beginning of that study, about 20% of people were wearing masks. However, in the same period one year later, most people were wearing masks because of the COVID-19 pandemic. Therefore, in this study, we examined the relationship between mask wearing, concentration of ionic components of PM2.5, respiratory symptoms, and PEFR. Seventy-two patients in Fukuoka City with asthma and allergic diseases measured PEFR daily and recorded respiratory symptoms and mask wearing in a diary. We measured the ionic components of PM2.5 in Fukuoka City and examined the relationships between patient measurements, mask wearing, and air pollution. Univariate analysis showed that, in 2020, but not in 2021, some ionic components of PM2.5, i.e., Cl−, NO3−, Na+, and Mg2+, were significantly correlated with the frequency of cough and nasal symptoms and a decrease in PEFR. Some ionic components of PM2.5 may increase the frequency of respiratory symptoms and decrease PEFR in patients with allergic diseases;however, this tendency is not seen when masks are used. The use of masks may be one of the factors that attenuate the effects of PM2.5 ionic components.