10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Size-resolved Endotoxin and Toxicity of Ambient Particles in Beijing and Switzerland
YANG YUE, Haoxuan Chen, Ari Setyan, Miriam Elser, Maria Dietrich, Jing Li, Ting Zhang, Xiangyu Zhang, Yunhao Zheng, Jing Wang, Maosheng Yao, Peking University
Abstract Number: 164 Working Group: Aerosol Toxicology
Abstract PM2.5 pollution has become a global health concern, however its size-resolved toxicity remains to be poorly understood for different geophysical locations. Here, we have studied the size-resolved particulate matter (PM) mass, metal and endotoxin distributions as well as their related toxicity in two regions (Beijing and Switzerland) with stark difference of air quality. Ambient airborne PM samples were collected from selected sites into 13 different size ranges (10 nm - 18 μm) using a cascade multi-stage impactor (NanoMoudi).
The results showed that the two different regions had strongly different PM mass distribution patterns. For example, the Swiss urban samples had a peak size at 40 nm with 23.3% of the total PM mass, while the Beijing sample featured two peak sizes at 0.75 μm and 4.23 μm with 13.8 - 18.6% and 13.7% - 20.4% of the total PM mass, respectively.
The oxidative potentials were analyzed by the dithiothreitol (DDT) assay, and the results revealed that PM in different sizes had different oxidizing potentials. The PM oxidative potentials were also depended on the PM source, even within the same city, e,g, a campus and a farm. For Beijing, the particles with the highest oxidative potentials were detected at size ranges around 40 nm, 130 nm, 240 nm and 7.48 μm; while for Swiss urban, they are located in the size range of 0.01 – 1 μm.
Metal analysis results indicated that the Beijing samples had higher Cd, As and Pb in the size range of 0.1 – 1 μm, while the Swiss samples had higher Cu, Mn and Fe in the size range above 10 μm. Particularly, the Swiss urban samples had higher Cr levels at 1 μm.
Furthermore, the endotoxin results showed that different environments had different size-resolved endotoxin distributions, typically having one peak in the ultrafine size range (40-100 nm) and another in the larger size range (1.3-13.4 μm). More importantly, endotoxin activity was detected in the PM with size well below 1 μm, which can penetrate down to the alveoli and can be translocated into the cell tissue and/or circulation system.
These data suggest strong differences in the emission sources and particle formation mechanisms for different cities, thus resulting in different oxidizing potentials. Accordingly, use of only the PM mass concentration could lead to erroneous concussions regarding its health effects. Endotoxin distribution suggested that larger particles could also possess strong oxidation potential. The obtained information can facilitate optimization of the air pollution control strategies, while maximizing health and economic benefits.