Assessment of airborne particles in indoor environments: Applicability of particle counting for prediction of bioaerosol concentrations

Indoor bioaerosols have recently received considerable interest because of their impact on health. In this study, concentrations of bioaerosols in relation to airborne particulate matter in various indoor environments were investigated. The comparative performance of two common biosamplers, including the single-stage Andersen impactor and the all-glass impinger (AGI) for bioaerosol sampling, was also evaluated. The average levels of airborne bacteria and fungi sampled by Andersen were 516 and 176 colony forming units (CFU) m^–3 and by AGI were 163 and 151 CFU m^–3, respectively. The highest bacterial levels were measured in residence apartments. The most predominant bacteria were belonged to Staphylococcus sp. and Arthrobacter sp. The Andersen impactor appeared to yield fungal concentrations that were comparable to the results obtained using the AGI biosampler. Meanwhile, Andersen impactor counts for bacteria were significantly higher than those obtained by AGI. Particle count data generated by the optical particle counter indicated that 95% of airborne particles were < 1 μm in diameter. Statistical analysis revealed a significant correlation between particle counts of PM1 and concentrations of culturable airborne bacteria measured with the both bioaerosol samplers. Based on these results, the Andersen impactor performed much better than the AGI for sampling airborne bioaerosols in low-contaminated indoor environments. Accurate measurement of microbial concentrations in indoor environments should be performed by bioaerosol monitoring; however, combining particle counting with bioaerosol sampling could provide prompt information about rapid variations of air quality.