In recent years, symptom-based deaths of asthmatics have become known to be due to mucus-induced airway obstruction. Asthma is one of the important diseases due to the biological effects of air pollutants. The purpose of this paper is to provide an overview of the findings on the involvement of airway mucus in asthma symptoms and to outline research up to 31 December 2022 on air pollutants and airway mucus. Moreover, airway mucus is also involved in the dyspnea of COVID-19, which has become a problem in recent years, and air pollutants that increase airway mucus may have some effects on COVID-19. In fact, the involvement of air pollutants in COVID-19 has also become a topic of discussion, so this paper also outlines the findings of COVID-19 and airway mucus to help speculate on the possible influence of air pollutants on COVID-19. Based on these findings, it is hoped that future research on airway mucus caused by air pollutants will occur.