Abundance and health risk of bioaerosols in the coastal areas of Qingdao, China

Bioaerosols can be spread through coughing, sneezing, respiratory droplets and aerosol particles, and public awareness of the health risks of bioaerosols has increased. Based on bioaerosol culturable microbe concentration data collected from March–December in 2015, 2018 and 2019, the health risks of bioaerosols were assessed by air quality level, month, population, and particle size using an average daily dose rate model. The concentration of culturable microorganisms is related to the air quality index (AQI). Under AQI values ranging from 51–100, the concentration of culturable microorganisms was the highest, while the concentration of culturable microorganisms was the lowest for AQI values ranging from 101–150. The health risk in June and July 2015 was the highest, the change trends in 2018 and 2019 were similar, the health risk was the highest in October, and the health risk of bioaerosols along the inhalation route was 10³–10⁴ times that along the exposure route. The health risk of bioaerosols was generally higher in summer and autumn than in spring and winter over the three-year period. The health risk for different categories of individuals indicated the same trend over the 3-year period, with the health risk for adults exceeding that for children and the health risk for men exceeding that for women. The health risk of bioaerosols was high under particle sizes ranging from 1.10–4.70 μm. The study results could provide data support for the analysis of bioaerosol-related health risks and offer a reference for the prevention and control of urban microbial diseases.