青岛近海冬季大气生物气溶胶中微生物活性研究

Microbial Activity in Bioaerosols in Winter at the Coastal Region of Qingdao

为了研究生物气溶胶中微生物活性水平和活性粒径分布特征,于2015年11月~2016年1月在青岛近海运用分级生物气溶胶采样器连续采集了生物气溶胶样品,并用荧光素二乙酸酯(fluorescein diacetate,FDA)水解法进行了活性测定.结果表明,采样期间青岛地区气溶胶中微生物活性水平(以荧光素钠计)范围为21.89~108.59 ng·m^(-3),平均值为59.43 ng·m^(-3).微生物活性的粒径分布呈现活性随粒径增大而增大,粗粒径(>2.1μm)高于细粒径(<2.1μm)的特征,在>7.0μm粗粒子上所占比例最高,平均为24.06%.冬季微生物活性在一天当中变化较大,并未呈现出明显的昼间变化规律.相关性分析显示采样期间微生物活性与风速之间存在显著正相关关系(r=0.445,n=33,**P<0.01),与温度、湿度和紫外线强度等气象因素以及AQI、PM_(2.5)、PM_(10)、CO、NO_2、O_3、SO_2等因子无显著相关性.气团来源对微生物活性具有明显影响.晴天微生物活性平均水平为100.33 ng·m^(-3),霾天微生物活性降低,平均水平降为56.53 ng·m^(-3),随着雾-霾天持续出现,活性迅速降低至晴天水平的37.7%,可见持续雾-霾天对微生物活性的影响更大.

In order to study the level and size distribution of microbial activity of atmospheric bioaerosols,bioaerosol samples were collected from November 2015 to January 2016 using size-fractionated bioaerosol samplers at the coastal region of Qingdao,and the microbial activity was measured using the fluorescein diacetate（ FDA） hydrolysis method. The results showed that the level of microbial activity was in the range of 21. 89-108. 59 ng·m^-3sodium fluorescein during the sampling period,with an average of 59. 43ng·m^-3sodium fluorescein in Qingdao. Size distribution of microbial activity exhibited a tendency,the activity increased with increasing particle size. The microbial activity on particles with coarse size（ 〉2. 1 μm） was higher than that on fine size,with the highest average proportion of 24. 06% for coarse size larger than 7. 0 μm. The daily variation of microbial activity was different for different samples,which showed no significant diurnal variation in winter. The correlation analysis showed that microbial activity was significantly correlated with wind velocity（ r = 0. 445,n = 33,＊＊P〈0. 01） during the sampling period. However,microbial activity showed no significant correlation with the meteorological factors,such as temperature,relative humidity and UV intensity during the sampling period. Moreover,there was no significant correlation of microbial activity with air quality factors,such as AQI,PM（2.5）,PM（10）,CO,NO2,O3 and SO2. Source of air mass had significant impact on microbial activity. The average level of microbial activity was 100. 33 ng·m^-3sodium fluorescein on sunny days,and the level decreased to 56. 53 ng·m^-3sodium fluorescein on hazy days.When the haze was mixed with fog and this special circumstance lasted for several days,the microbial activity reduced to 37. 7% of the level of sunny days. Therefore,consecutive hazy weather had great influence on microbial activity.