The Microbial Activity in PM2.5 in Indoor Air: As an Index of Air Quality Level

Abstract

Bioaerosols are a major source of pollution in indoor environments, where people spend approximately 90% of their time, and the microorganisms adhered to PM2.5 adversely affect human health. However, most research has focused on the concentration of these aerosols and the factors that influence it rather than the correlation between microbial activity and air quality. Thus, this study used a modified technique of fluorescein diacetate (FDA) hydrolysis to evaluate the activity of microorganisms in the PM2.5 during three seasons (summer, autumn and winter) in Beijing. 0.155-5.388 ng m -3 and 0.091-5.740 ng m -3 of sodium fluorescein, a marker of microbial activity, were measured indoors and outdoors, respectively; thus, no significant difference in concentration between the two environments was detected, but the indoor activity was affected by outdoor conditions to an extent. The most active season was autumn, followed by winter and summer. Furthermore, the highest activity in summer and autumn was observed during conditions of excellent air quality, and in summer, the activity during conditions of good air quality also obviously exceeded that during conditions of slight pollution. Additionally, the microbial activity in a room varied according to the room's ventilation (or lack thereof), suggesting a strong association between these parameters. In general, when the air quality was excellent, 20 minutes of ventilation achieved the optimal air exchange, but this duration should be reduced during polluted conditions. Our results provide new insights into evaluating the indoor air quality based on the microbial activity.

Polybrominated Dibenzo-p-dioxins/Furans (PBDD/Fs) and Diphenyl Ethers (PBDEs) in the Indoor and Outdoor of Gymnasiums

“…PM2.5 is ubiquitously existed in the indoor and outdoor environment (Bai et al, 2021;Navinya et al, 2020;Yu et al, 2021). Several types of environmental pollutants, including metals, organic compounds, and microbes, are contaminated on PM2.5 (Chen et al, 2021;Shen et al, 2020;Siudek and Ruczyńska, 2021;Vega et al, 2021). To raise the public concerns, PM2.5 has been demonstrated to cause the adverse effects on animal models and human bodies (Chao et al, 2018;Chung et al, 2020;Zhang et al, 2020).…”

Particulate matter in a lockdown home: evaluation, calibration, results and health risk from an IoT enabled low-cost sensor network for residential air quality monitoring

“…6,7 There are a number of existing studies that assess indoor particulate matter (PM) pollution, however a frequent limitation of these studies is monitoring is limited to only 1 or 2 locations within a property (oen a kitchen or main living area). 4,[8][9][10][11][12][13][14][15][16][17][18][19][20][21] 35 reported a comprehensive multi-room study with multiple sensors, yet this was limited to PM 2.5 (particles with aerodynamic diameters <2.5 mm) as the sensors were not calibrated for the PM 1 & PM 10 (particles with diameters <1 mm and <10 mm respectively) fractions that they also monitored. Few previous studies have used IoT networks for monitoring, and those that did, tended to use IoT networks that are reliant on gateway or WiFi technology thus limiting deployment.…”

Microbial activity and community structure in PM2.5 at different heights in ground boundary layer of Beijing atmosphere under various air quality levels

“…Studies of Chen et al . (2021b) have shown that the indoor microbial activity in winter is closely related to the window ventilation state and indoor environment. Meng et al .…”

“…In addition, microbial activity increased in heavy and severe pollution (>200). Studies of Chen et al (2021b) have shown that the indoor microbial activity in winter is closely related to the window ventilation state and indoor environment. Meng et al (2016) found that microbial activity increases with an increase in particle size, but there are also studies (Chen et al, 2021a) that have found no significant difference in microbial activity between PM 2.5 and PM 10 .…”