Microorganisms associated particulate matter: A preliminary study

摘要

This study aims to determine the microbiological quality of particulate matter (PM) in an urban area in Jeddah, Saudi Arabia, during December 2012 to April 2013. This was achieved by the determination of airborne bacteria, fungi, and actinobacteria associated PM_(10) and PM_(2.5), as well as their relationships with gaseous pollutants, O_3, SO_2 and NO_2, and meteorological factors (T℃, RH% and Ws). High volume samplers with PM_(10) and PM_(2.5) selective sizes, and glass fiber filters were used to collect PM_(10) and PM_(2.5), respectively. The filters were suspended in buffer phosphate and aliquots were spread plated onto the surfaces of trypticase soy agar, malt extract agar, and starch casein agar media for counting of bacteria, fungi and actinobacteria-associated PM, respectively. PM_(10) and PM_(2.5) concentrations averaged 159.9 μg/m~3 and 60 μg/m~3, respectively, with the ratio of PM_(2.5)/PM_(10) averaged ～0.4. The concentrations of O_3, SO_2 and NO_2 averaged 35.73 μg/m~3, 38.1 μg/m~3 and 52.5 μg/m~3, respectively. Fungi and actinobacteria associated PM were found in lower concentrations than bacteria. The sum of microbial loads was higher in PM_(10) than PM_(2.5), however a significant correlation (r = 0.57, P ≤ 0.05) was found between the sum of microbial loads associated PM_(10) and PM_(2.5). Aspergillus fumigatus and Aspergillus niger were the common fungal types associated PM. Temperature significantly correlated with both PM_(10) (r = 0.44), and PM_(2.5) (r = 0.5). Significant negative correlations were found between O_3 and PM_(2.5) (r = -0.47), and between SO_2 with PM_(10) (r = - 0.48). Wind speed positively correlated with airborne microorganisms associated PM. The regression model showed that the inverse PM_(2.5) concentration (1/PM_(2.5)) was a significant determinant of fungal count associated PM. Chemical processes and environmental factors could affect properties of PM and in turn its biological quality.