Fine particulate matter and airborne microorganisms in bangkok

Abstract

Outdoor airborne microbial associated fine particulate matter was comparatively investigated in urban, suburban, and roadside area of Bangkok. Fine particulate matter was collected for 7 days in each site from June to November 2009. Personal air samplers equipped with cascade impactors at a flow rate of 1.7 l/min were used for air sampling. The quantities of particulate matter and airborne microorganisms at ambient urban and suburban areas are comparable, but are remarkably different from roadside area. At roadside area, and airborne bacterial concentration significantly different from other sampling sites. Most of bacterial cultures at urban and roadside area are gram positive cocci while those at suburban area are gram negative cocci. In addition, the major types of airborne bacteria found at all sampling sites are P. fluorescens, S. sciuri, and B. pumilus, and the major types of airborne fungi are Penicillium spp. and Aspergillus spp. Intriguingly, particulate matter levels are associated with the airborne microorganism concentrations only at suburban area. At this site, fine particulate matter is correlated with airborne bacteria (r=0.62, P=0.05) and airborne fungi (r=0.61, P=0.05). Moreover, meteorological parameters are significantly correlated with both particulate matter and microbial count concentrations at p = 0.01 and p = 0.05.