Knowledge and behaviour of community residents' face mask-wearing during the COVID-19 pandemic: a cross-sectional study in Shanghai, China

Objectives COVID-19 is an infectious disease spreading through respiratory droplets. Using a face mask correctly is one of the essential preventive measures. We launched a survey to discover the current face mask-wearing problems for better prevention and control of the pandemic. Setting/participants A cross-sectional study was conducted with 1240 residents in Shanghai during 18-28 February 2020. Stratified random sampling was adopted in the urban area, urban-rural fringe area and rural area. A mobile self-designed questionnaire was used. Main outcome measures Analysis of the demographic and sociological factors influencing residents' face mask type selection, disposable surgical mask-wearing behaviour, replacement time and the storage method for reuse of disposable surgical masks. Results The accuracy of residents' face mask type selection was rated 41.61% (513/1233), and that of urban-rural fringe residents, low-education residents, elderly residents, were low, respectively (p<0.001). 96.67% of residents always wore face masks in crowded public places. Multiple-factor analysis showed that region, gender and education level were the influencing factors for entirely fitting the disposable surgical mask to the face. Region was an influencing factor for not touching the mask's external surface while wearing or removing it. Education level was an influencing factor for recognising the external and inner mask surface, upper and lower edge of a disposable surgical mask. The accuracy of the mask replacement time was 25.63% (316/1223). It was low with elderly, low-education residents, respectively (p<0.001).The accuracy of residents' storage method for reuse of disposable surgical mask was 3.81% (47/1233), and region, age and education level were influencing factors. Conclusions Shanghai residents recorded a high rate of wearing face masks. Selection of an appropriate type of face mask, disposable surgical mask-wearing behaviour, replacement time and storage method for reuse of disposable surgical masks should be particularly emphasised in future behaviour change interventions.