The Study of Ambient Air Bioaerosols During Summer Daytime and Nighttime Periods in Taichung, Central Taiwan

Abstract

Suspended particles, of which bioaerosols are one type, constitute one of the main reasons for poor air quality in Taiwan. Bioaerosols include allergens such as fungi, bacteria, actinomycetes, arthropods, and protozoa, as well as microbial products such as mycotoxins, endotoxins, and glucans. When allergens and microbial products are suspended in the air, local air quality will be influenced severely. When the particle size is small enough to pass through the respiratory tract entering the human body, the health of the local population is threatened. Therefore, the purpose of this study was to understand the concentration and types of bacteria during the summer period at four sampling sites in Taichung, central Taiwan. The total average bacterial concentrations at 48-h incubation time during the summer daytime period were 8.1 × 102, 1.9 × 103, 3.7 × 10 3, and 1.1 × 103 cfu/m3 and nighttime period were 1.1 × 103, 2.6 × 103, 3.2 × 103, and 1.9 × 103 cfu/m3 from June 30 to August 1, 2005. The average bacterial concentration increased as the incubated time increased for each particle size range. The high average bacterial concentration was found in the particle size 0.34–0.71 mm (average bioaerosol size was in the range of 1.1–4.7 μm) for each sampling site. There were more than 20 types of bacteria at each sampling site and the bacteria shapes were rod, coccus, and filamentous.