AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Impacts of Ambient Bioaerosols to an Unoccupied Indoor Bioaerosols during and after the Hazy Events
FENG ZHOU, Mutong Niu, Tianle Zhu, Fangxia Shen, Beihang University
Abstract Number: 470 Working Group: Bioaerosols
Abstract People spend most of their time indoors. Inhalation of bacterial aerosols is linked to series of adverse health problems, such as rhinitis, asthma and chronic bronchitis. Indoor microbial sources include human, surface dust, ambient atmosphere and so on. As the heavily polluted weather happens frequently in China and other regions, there are a growing body of studies regarding the bioaerosols in the ambient environments. This furtherly raises the health concern of indoor bioaerosols originated from the polluted ambient air. Here we performed a sampling campaign in an indoor environment without occupants, aiming to identify the contribution of outdoor source to indoor airborne bacteria. Air samples were collected from the indoor room and the adjacent outdoor air simultaneously every two hours on both clean and polluted days with a high-flow portable biological aerosol trap (HighBioTrap P-1000). The ACR (air change rate) of the indoor room were measured by using CO2as a tracer gas. Levels of total bacteria and viable bacteria were quantified with qPCR (quantitative polymerase chain reaction) and PMA-qPCR, respectively. Meanwhile, the bacterial community structure was identified by a high-throughput sequencing technique.
Preliminary qPCR results showed that the concentrations of outdoor total and viable bacteria were higher than that of the indoor environment. Significant correlation was seen between outdoor total bacteria and indoor total bacteria (r=0.58923, p<0.05), indicating the contribution of outdoor bacteria to that of the indoor. Nevertheless, the correlation between the indoor and outdoor viable bacteria was not seen. This may be due to that the viability of indoor bacteria is affected by various factors. The concentrations of outdoor viable bacteria were poorly correlated with PM2.5, PM10, but significantly correlated with outdoor gaseous pollutants O3, SO2, NO2 and CO (p<0.05). Further analyses are necessary to figure out the contribution of outdoor source to the indoor bioaerosols. These preliminary results also suggest the importance of considering the indoor air pollutants regarding the status of indoor airborne microbes.