Wei Wen-Shu, Qi Jian-Hua, Chang Cheng
Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China.
Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China.
Huan Jing Ke Xue. 2023 Jan 8;44(1):127-137. doi: 10.13227/j.hjkx.202202071.
Bacteria are the most abundant microorganisms in atmospheric bioaerosols, widely distributed in the environment. Bioaerosol samples were collected using the FA-1 impact sampler from October 2013 to January 2021 in the coastal city of Qingdao, and samples stained with a BacLight bacterial viability kit were used to measure the concentrations of viable and non-viable bacteria with an epifluorescence microscope. The viable and non-viable bacteria in bioaerosols were characterized during different seasons, with particular attention paid to the distribution characteristics of bacteria on foggy, hazy, and dust days. The results showed that the mean concentrations of total bacteria were (1.06±0.68)×10 cells·m in Qingdao during the sampling period, and those of viable and non-viable bacteria were (8.20±4.88)×10 cells·mand (9.74±6.72)×10 cells·m, respectively. The seasonal concentrations of non-viable bacteria were the highest in spring and winter and the lowest in summer, whereas that of viable bacteria was highest in spring, followed by those in summer and autumn, and the lowest in winter. Atmospheric bacterial concentrations fluctuated with by month, and total bacteria presented a similar variation pattern with that of non-viable bacteria. The monthly average concentration of non-viable bacteria showed the highest value in March during the spring and the lowest in June during the summer in 2021, whereas the highest value for viable bacteria occurred in May during the spring in 2021 and the lowest in December during the winter in 2020. Viable bacteria concentrations were significantly positively correlated with temperature and significantly negatively correlated with NO, SO, and CO. Non-viable bacteria were significantly positively correlated with PM. The bacteria in bioaerosol particles showed bimodal, unimodal, and skewed size distributions, varying with season and month. Under different weather conditions, the concentration of non-viable bacteria on dusty days was significantly higher than that on sunny, foggy, or hazy days, but the bacteria viability was as low as 6.85% due to long-distance transport. Anthropogenic pollution resulted in the lowest viability of bacteria at 4.10% on hazy days, whereas the highest viability in bacteria was 16.26% on foggy days due to high humidity. The size distribution of bacteria in bioaerosol particles under different pollution days showed a bimodal distribution, and the peak size depended on the weather type.
细菌是大气生物气溶胶中数量最多的微生物，广泛分布于环境中。2013年10月至2021年1月期间，在沿海城市青岛使用FA - 1撞击式采样器采集生物气溶胶样本，并用BacLight细菌活力试剂盒染色后的样本通过落射荧光显微镜测量活菌和死菌的浓度。对不同季节生物气溶胶中的活菌和死菌进行了表征，特别关注了雾天、霾天和沙尘天细菌的分布特征。结果表明，采样期间青岛总细菌的平均浓度为(1.06±0.68)×10⁴个细胞·m⁻³，活菌和死菌的平均浓度分别为(8.20±4.88)×10³个细胞·m⁻³和(9.74±6.72)×10³个细胞·m⁻³。死菌的季节浓度在春季和冬季最高，夏季最低，而活菌的季节浓度在春季最高，其次是夏季和秋季，冬季最低。大气细菌浓度随月份波动，总细菌与死菌呈现相似的变化模式。2021年春季3月死菌的月平均浓度最高，夏季6月最低，而2021年春季5月活菌的浓度最高，2020年冬季12月最低。活菌浓度与温度呈显著正相关，与NO、SO₂和CO呈显著负相关。死菌与PM呈显著正相关。生物气溶胶颗粒中的细菌呈现双峰、单峰和偏态的粒径分布，随季节和月份而变化。在不同天气条件下，沙尘天死菌浓度显著高于晴天、雾天或霾天，但由于长距离传输，细菌活力低至6.85%。人为污染导致霾天细菌活力最低，为4.10%，而雾天由于湿度高，细菌活力最高，为16.26%。不同污染天数下生物气溶胶颗粒中细菌的粒径分布呈现双峰分布，峰值粒径取决于天气类型。
