ABSTRACT

The present study, for the first time, evaluated the seasonal variation of PM₁₀-associated bacterial and fungal concentrations at four locations (CARS premises, Doyel Chattar, Postogola, and Chittagong Road) in Dhaka, Bangladesh. In this study, PM₁₀ samples were collected four times on 20.3 × 25.4 cm irradiated glass fibre filter from November 2018 to August 2019. The concentrations of total airborne bacteria (14,073 ± 8,897 CFU/m³) were found to be significantly higher (one-way ANOVA; p < 0.05) in Chittagong Road, which is known for traffic congestion, than that of the other locations. The total airborne bacterial concentrations occurred in the following descending order: winter>spring>summer>rainy. Bacillus spp. and Staphylococcus spp. were found to be the dominant species present in PM₁₀ particles. Based on Pearson correlation analysis and stepwise multiple-regression analysis, relative humidity was found to be the most important variable controlling the concentrations of total airborne bacteria. Common fungi such as Aspergillus, Penicillium, Cladosporium and Fusarium genera were identified in the PM₁₀ samples. The highest fungal concentration (1,974 ± 1,173 CFU/m³) was found at Chittagong Road. The total fungal spore concentrations occurred in the following descending order: summer>spring>winter>rainy. From correlation analysis and stepwise regression analysis, the temperature was found to be the most important variable influencing the concentrations of fungi in PM₁₀ samples. A dose-rate estimation study revealed that the children were more vulnerable compared to adults with respect to exposure to bacterial and fungal dose rates. The present study has enormous implications considering the health hazards the bacterial and fungal communities pose to humans.

摘要

本研究首次评估了孟加拉国达卡四个地点（CARS 场所、Doyel Chattar、Postogola 和吉大港路）PM ₁₀相关细菌和真菌浓度的季节性变化。在这项研究中，从 2018 年 11 月到 2019 年 8 月，在 20.3 × 25.4 cm 辐照玻璃纤维过滤器上收集了四次PM ₁₀样本。发现空气中细菌总数（14,073 ± 8,897 CFU/m ³）显着更高（一个-way ANOVA; p < 0.05) 在以交通拥堵而闻名的吉大港路，比其他地点的路段多。空气中总细菌浓度按以下降序发生：冬季>春季>夏季>多雨。芽孢杆菌属 和葡萄球菌属 被发现是 PM ₁₀颗粒中存在的主要物质。基于 Pearson 相关分析和逐步多元回归分析，发现相对湿度是控制空气传播细菌浓度的最重要变量。在 PM ₁₀样本中发现了常见的真菌，例如曲霉属、青霉属、枝孢属和镰刀菌属。最高真菌浓度 (1,974 ± 1,173 CFU/m ³) 在吉大港路被发现。总真菌孢子浓度的降序为：夏季>春季>冬季>多雨。通过相关分析和逐步回归分析，发现温度是影响 PM ₁₀样品中真菌浓度的最重要变量。一项剂量率估计研究表明，在接触细菌和真菌剂量率方面，儿童比成人更容易受到伤害。考虑到细菌和真菌群落对人类造成的健康危害，本研究具有巨大的意义。