Tingna Liu

The implication of carbonaceous aerosol to the formation of haze: Revealed from the characteristics and sources of OC/EC over a mega-city in China

The characteristics and sources of organic carbon (OC) and elemental carbon (EC) in PM(2.5) in 2006-2007 as well as their impact on the formation of heavy haze in Shanghai were investigated. Daily average concentrations of OC and EC ranged from 1.8 to 20.1 μg m(-3) and 0.5-7.8 μg m(-3) with averages of 7.2 and 2.8 μg m(-3), respectively. The carbonaceous aerosol (OC plus EC) contributed to ∼ 27.2% of the total mass of PM(2.5) on annual average. Obvious seasonal variation was observed in both OC and EC. The percentage of secondary organic carbon (SOC) contributed to OC was in a range of 2.4-66.8%, with an average of 40.1%. Three types of haze were classified based on their chemical composition. OC, EC, SO(2)/NO(2) (in turn, SO(4)(2-)/NO(3)(-)) were responsible for the formation of the three types of haze, respectively. The carbonaceous aerosol was one of the key factors in the formation of haze. Local emissions were the dominant sources of OC and EC in warm seasons, and long-range transport had a significant contribution to OC and EC in PM(2.5) in spring and winter in Shanghai.

Signal Transductions of BEAS-2B Cells in Response to Carcinogenic PM2.5 Exposure Based on a Microfluidic System

PM2.5 (particulate matter less than 2.5 μm in diameter) is considered as a harmful carcinogen. Determining the precise relationship between the chemical constituents of PM2.5 in the air and cancer progression could aid the treatment of environment related disease and establishing risk reduction strategies. Herein, we used transcriptomics (RNA-seq) and an integrated microfluidic system to identify the global gene expression and differential target proteins expression induced by ambient fine particles collected from the heavy haze in China. The results clearly indicated that cancer related pathways exhibited the strongest dysregulation. The ambient fine particles could be uptaken into the cells by pinocytosis, mainly promoting the PI3K-Akt pathway, FGF/FGFR/MAPK/VEGF signaling, and the JAK-STAT pathway, leading to evading apoptosis, sustained angiogenesis, and cell proliferation, which are the most important hallmarks of cancer. And fine particles also have been demonstrated to create intracellular reactive oxygen species (ROS) and mitochondrial ROS, change intracellular free Ca2+, and induce apoptosis, which are all key players in mediating cancer progression. It was observed by transmission electron microscopy (TEM) that the particles from the haze could enter the mitochondria, resulting in disturbance of the mitochondrial membrane and disruption of the mitochondria, and these particles can even enter inside the nucleus. It was also found in our study of organics (OC, PAHs) and metals (Zn, As, V) that compounds of fine particles were more closely associated with the exacerbation of cancer and secondary aerosols generated by traffic had the largest impact on cancer related signal transductions.