State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
Department of Environmental Engineering Sciences, Engineering School of Sustainable Infrastructure and Environment, University of Florida, Gainesville, FL 32611, USA.
Sci Total Environ. 2016 Apr 15;550:751-759. doi: 10.1016/j.scitotenv.2016.01.137. Epub 2016 Feb 2.
The chemical characteristics of airborne particulate matter (PM) have been extensively studied; however, little information exists for its biological components (bioaerosol) especially during a haze event in mega cities. Herein, we studied the bioaerosol (fluorescent particle) dynamics on both haze and sunny days in Beijing from Dec. 2013 to March 2014 by employing a widely used real-time bioaerosol sensor-ultraviolet aerodynamic particle spectrometer (UV-APS). Firstly, we studied the fluorescent particle (BioPM) concentration and size distributions during three independent haze and three independent sunny days. Secondly, we investigated BioPM dynamics over a two-week long monitoring period which included consecutive haze days and alternated sunny days. In addition, we analyzed bacterial community structures and endotoxin levels in the air samples using pyrosequencing and Limulus amebocyte lysate (LAL) method, respectively. More than 6-fold higher fluorescent particle concentrations up to 5×10(5)/m(3) with peaks at night or early dawn were detected at the time of haze occurrences than those observed on sunny days. When the haze episode progressed for 3-5days, the BioPM concentrations were observed to decrease to the levels that were typically observed on sunny days. In general, ozone levels were found to be elevated at noon, while BioPM, NOx and relative humidity were reduced. Gene sequence analysis revealed no significant difference in abundances and community structures for top 13 bacterial genera between haze and sunny days, yet about twice higher endotoxin levels (12.4EU/m(3)) were detected on haze days than on sunny days. The results here facilitate a better understanding of atmospheric fluorescent particle dynamics including those under haze events.
空气中颗粒物（PM）的化学特性已得到广泛研究，但有关其生物成分（生物气溶胶）的信息却很少，特别是在特大城市的雾霾事件期间。在此，我们通过使用广泛使用的实时生物气溶胶传感器-紫外线空气动力学颗粒谱仪（UV-APS），研究了 2013 年 12 月至 2014 年 3 月北京雾霾天和晴天的生物气溶胶（荧光颗粒）动态。首先，我们研究了三个独立的雾霾天和三个独立的晴天期间荧光颗粒（BioPM）浓度和粒径分布。其次，我们在为期两周的监测期间研究了 BioPM 的动态，其中包括连续的雾霾天和交替的晴天。此外，我们分别使用焦磷酸测序和鲎变形细胞溶解物（LAL）方法分析了空气中细菌群落结构和内毒素水平。在雾霾发生时，荧光颗粒浓度比晴天高出 6 倍以上，最高可达 5×10(5)/m(3)，峰值出现在夜间或黎明时分。当雾霾事件持续 3-5 天时，BioPM 浓度观察到降低到通常在晴天观察到的水平。一般来说，中午时臭氧水平升高，而 BioPM、NOx 和相对湿度降低。基因序列分析显示，在雾霾天和晴天之间，前 13 种细菌属的丰度和群落结构没有明显差异，但雾霾天的内毒素水平（12.4EU/m(3)）比晴天高两倍左右。这些结果有助于更好地了解大气荧光颗粒动力学，包括雾霾事件期间的情况。
