Residential airborne culturable fungi under general living scenario: On-site investigation in 12 typical cities, China.

Abstract Background Residential airborne fungi may present obvious risk to human health. However, many countries do not recognize the necessarily need to control residential airborne culturable fungi (RAF). In China, few systemic investigations have been conducted to illustrate the distribution of residential airborne fungi and identify the association between indoor influencing variables and RAF under general living scenario in China. Objective This study aimed to investigate RAF with the on-site research of 12 typical cities in China, and provided the latest characteristics and potential influencing factors of RAF under general living scenario. Methods We measured RAF and investigated residential characteristics in 12 typical cities in China, 2018. At least 50 resident families were randomly selected both from downwind and upwind districts in each city with pre-proposed requirements. The RAF were sampled by the six-stage Anderson impactor. PM2.5 and PM10 were monitored by calibrated light-scattering dust meters. CO and CO2 were monitored by non-dispersive infrared analyzer method. NO2 was determined by Saltzman method. General linear model was used to evaluate the association between RAF exposure and residential characteristics with adjustment for potential confounders. Results The RAF concentrations ranged from 0 to 9371 CFU/m3 with a median concentration of 396 CFU/m3. The median concentrations of RAF in the warm season were statistically higher than the cold season in Panjin, Qingdao, Lanzhou and Luoyang, but lower than the cold season in Shijiazhuang, Ningbo and Nanning. RAF in the bedrooms were more than the living rooms in all cities except Xi'an. Temperature and humidity had an interactive effect on the RAF (OR = 1.0006, 95% CI: 1.0005, 1.0006). Some residential environmental pollutants, including PM2.5 (OR = 0.9989, 95% CI: 0.9988, 0.9989), PM10 (OR = 0.9993, 95% CI: 0.9993, 0.9993), and CO2 (OR = 0.0236, 95% CI: 0.0230, 0.0243), were negatively correlated with RAF. CO (OR = 1.1450, 95% CI: 1.1433, 1.1467) and NO2 (OR = 1.0026, 95% CI: 1.0024, 1.0028) were positively correlated with RAF. Architectural characteristics (sunlight exposure, building history, longitude, latitude, total living area, living floor, distance from the road, house type, the layers of window glass and decoration), family-related information (income) and lifestyle behaviors (keeping pets, growing plants, cooking, using insecticide, burning incense, heating, using air conditioner and cleaning frequencies) were also significantly related with RAF. Conclusions This study reported nation-wide baseline condition of RAF and related influencing factors under general living scenario with quantitative details, which are exceedingly promising for evidence-driven standard and reasonable control strategy of residential airborne culturable in China.