西安市秋冬季不同空气质量下可培养微生物气溶胶浓度和粒径分布

利用Anderson空气微生物采样器对西安市2014年9月~2015年1月间可培养微生物气溶胶进行采样、培养,分析不同空气质量下其浓度与粒径变化特征,并对其与颗粒污染物(PM_(2.5)、PM_(10))、气象参数(温度、相对湿度)和其它气态污染物(NO_2、SO_2、O_3)进行主成分+多元线性回归分析.结果显示,可培养细菌和真菌气溶胶浓度范围分别为97~1 909CFU·m~(-3),92~1 737 CFU·m~(-3).随空气污染程度加深,两种微生物气溶胶浓度均呈现增加趋势;细菌气溶胶粒径分布向粗颗粒偏移;而真菌气溶胶在低污染时呈正态分布,高污染时粒径峰值向细颗粒偏移.主成分分析结果显示,可培养微生物气溶胶主要与灰霾、太阳辐射和相对湿度有关.多元线性回归结果表明,细菌气溶胶与灰霾呈显著正相关(P0.05),与太阳辐射呈不显著负相关,与湿度呈不显著正相关;真菌气溶胶与灰霾、太阳辐射和相对湿度均呈不显著正相关.研究结果可以为评估微生物气溶胶所引起的环境与健康效应提供基础数据.

Concentration and Size Distribution Characteristics of Culturable Bioaerosols at Various Air Quality Levels During Fall and Winter in Xi'an, China

The concentration and size distribution of culturable bacteria and fungi were studied in Xi''an city at various air quality levels. The culturable bioaerosols were collected by an Andersen bioaerosol aerosol sampler between Sept. 2014 and Jan. 2015. Principal component analysis and multiple linear regressions were applied to link the concentrations with meteorological conditions including ambient temperature and relative humidity, as well as the levels of air pollutants such as PM_2.5, PM₁₀, NO₂, SO_2, and O₃. These measured results showed that the concentration of culturable bacteria and fungi were in the ranges of 97-1909 CFU·m^-3 and 92-1737 CFU·m^-3, respectively. The concentrations of culturable bioaerosols increased along with a deterioration in air quality. The size distribution of the bacteria migrated to coarse particles. Fungal aerosols showed a normal distribution at low pollution levels, while for a high levels, they preferenced fine particles. Results from the principal component analysis (PCA) indicate that the concentration of culturable bioaerosols is mainly influenced by haze, solar radiation, and relative humidity. Multiple linear regression analysis showed that bacterial aerosol concentrations are positively correlated with haze (P<0.05) and relative humidity, while no significant negative correlations with solar radiation exists. Fungal aerosol concentrations did not have significant positive correlations with haze, solar radiation, or relative humidity. The results of this study will provide basic data for evaluating the effects of bioaerosols on human health and the environment.