Yang Liu, Shen Zhenxing, Wang Diwei, Wei Junqiang, Wang Xin, Sun Jian, Xu Hongmei, Cao Junji
Department of Environmental Science and Engineering Xi'an Jiaotong University Xi'an China.
Key Lab of Aerosol Chemistry & Physics SKLLQG Institute of Earth Environment Chinese Academy of Sciences Xi'an China.
Geohealth. 2021 May 1;5(5):e2021GH000411. doi: 10.1029/2021GH000411. eCollection 2021 May.
Bioaerosols have a major negative effect on air quality and on public health by causing the spread of diseases. This study evaluated the bioaerosol composition and variation in a semi-arid megacity of northwest China from October 2019 to January 2020 using an Andersen six-stage impactor sampler. The size distribution, diurnal variations of the concentrations of airborne bacteria, airborne fungi, and total airborne microbes (TAM) were investigated in autumn and winter. The mean concentrations of airborne bacteria, fungi, and TAM were 523.5 ± 301.1 colony-forming units (CFU)/m, 1318.9 ± 447.8 CFU/m, and (7.25 ± 1.90) × 10 cells/m, respectively, in autumn and 581 ± 305.4 CFU/m, 1234.4 ± 519.9 CFU/m, and (5.96 ± 1.65) × 10 cells/m, respectively, in winter. The mean bioaerosol concentrations were slightly higher on nonhaze days than on haze days, but the difference was not statistically significant. Higher ambient particulate matter levels and atmospheric oxidation capacity inhibited bacteria survival. The diurnal maximum bioaerosol concentration was observed in the morning in autumn, whereas in winter, bioaerosols did not exhibit such a distribution, the impact of human activities on bioaerosols was still uncertain. The size of airborne bacteria exhibited a bimodal distribution, whereas a unimodal pattern was observed for fungi and TAM. Most bacteria, fungi, and TAM were distributed in the respirable ranges from trachea and primary bronchi to alveoli, indicating that bioaerosols have a high risk of being inhaled and causing respiratory diseases in Xi'an.
生物气溶胶通过引发疾病传播，对空气质量和公众健康产生重大负面影响。本研究于2019年10月至2020年1月期间，在中国西北半干旱特大城市使用安德森六级撞击式采样器，评估了生物气溶胶的组成及变化情况。对秋冬季节空气中细菌、真菌及总空气微生物（TAM）的浓度大小分布、日变化进行了调查。秋季空气中细菌、真菌和TAM的平均浓度分别为523.5±301.1菌落形成单位（CFU）/立方米、1318.9±447.8 CFU/立方米和（7.25±1.90）×10⁴个细胞/立方米，冬季则分别为581±305.4 CFU/立方米、1234.4±519.9 CFU/立方米和（5.96±1.65）×10⁴个细胞/立方米。非霾天的生物气溶胶平均浓度略高于霾天，但差异无统计学意义。较高的环境颗粒物水平和大气氧化能力抑制了细菌的存活。秋季生物气溶胶浓度日最大值出现在早晨，而冬季生物气溶胶未呈现此种分布，人类活动对生物气溶胶的影响仍不确定。空气中细菌大小呈双峰分布，而真菌和TAM呈单峰分布。大多数细菌、真菌和TAM分布在从气管、一级支气管到肺泡的可吸入范围内，这表明西安的生物气溶胶具有较高的被吸入并引发呼吸道疾病的风险。
