Qiongzhen Wang

Mixing of Asian dust with pollution aerosol and the transformation of aerosol components during the dust storm over China in spring 2007

NO3 and NH4 decreased owing to the dilution of the local pollution by the invaded dust. The western dust contained relatively low anthropogenic aerosols, and it mainly derived from the Taklimakan Desert, a paleomarine source. The northwestern dust had a considerable chemical reactivity and mixing with sulfur precursors emitted from the coal mines on the pathway of the long‐range transport of dust. The northeastern dust reached Shanghai with high acidity, and it became the mixed aerosol with the interaction among dust, local pollutants, and sea salts. Comparison of the speciation of the water‐soluble ions on both nondust and dust days at all sites illustrated the evolution of major ion species from different dust sources during the long‐range transport of dust. The mixing mechanisms of the dust with the pollution aerosol on the local, medium‐range, and long‐range scale revealed from this study would improve the understanding of the impacts of Asian dust on the regional/global climate change.

Mixing of dust with pollution on the transport path of Asian dust — Revealed from the aerosol over Yulin, the north edge of Loess Plateau

Both PM(2.5) and TSP were monitored in the spring from 2006 to 2008 in an intensive ground monitoring network of five sites (Tazhong, Yulin, Duolun, Beijing, and Shanghai) along the pathway of Asian dust storm across China to investigate the mixing of dust with pollution on the pathway of the long-range transport of Asian dust. Mineral was found to be the most loading component of aerosols both in dust event days and non-dust days. The concentrations of those pollution elements, As, Cd, Pb, Zn, and S in aerosol were much higher than their mean abundances in the crust even in dust event days. The high concentration of SO(4)(2-) could be from both sources: one from the transformation of the local emitted SO(2) and the other from the sulfate that existed in primary dust, which was transported to Yulin. Na(+), Ca(2+), and Mg(2+) were mainly from the crustal source, while NO(3)(-) and NH(4)(+) were from the local pollution sources. The mixing of dust with pollution aerosol over Yulin in dust event day was found to be ubiquitous, and the mixing extent could be expressed by the ratio of NO(3)(-)/Al in dust aerosol. The ratio of Ca/Al was used as a tracer to study the dust source. The comparison of the ratios of Ca/Al together with back trajectory analysis indicated that the sources of the dust aerosol that invaded Yulin could be from the northwestern desert in China and Mongolia Gobi.

Postoperative respiratory and analgesic effects of dexmedetomidine or morphine for adenotonsillectomy in children with obstructive sleep apnoea

The postoperative respiratory and analgesic effects of dexmedetomidine and morphine have not been compared in children with sleep apnoea having adenotonsillectomy. In a randomised double‐blind study we recruited 60 children, aged 2–13 years, who received either intravenous dexmedetomidine 1 μg.kg−1 or morphine 100 μg.kg−1 on anaesthetic induction. End‐tidal carbon dioxide, Children’s Hospital of Eastern Ontario Pain Scale score and supplementary morphine administration were recorded every 15 min for 60 min postoperatively. Over 60 min, mean (SD) end‐tidal carbon dioxide was consistently lower with dexmedetomidine compared with morphine (5.4 (0.7) kPa vs 6.0 (0.6) kPa, respectively; p = 0.001). Mean (SD) pain scores were higher with dexmedetomidine (8.1 (2.0) immediately postoperatively and 6.7 (1.0) at 60 min vs 7.6 (1.8) and 6.3 (0.7), respectively, with morphine (p = 0.023)). More patients required supplementary morphine with dexmedetomidine (13/30 (43%) vs 21/30 (70%); p = 0.037). Postoperatively, dexmedetomidine produced less respiratory depression than morphine, but less effective analgesia.

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.

First long-term detection of paleo-oceanic signature of dust aerosol at the southern marginal area of the Taklimakan Desert

We firstly conducted a long-term in-situ field measurement at a marginal area (Hotan) of the southern Taklimakan Desert covering all four seasons. Detailed chemical characterization of dust aerosol over Hotan showed several unconventional features, including (1) ubiquity of high Na+ and Cl− abundances in the Taklimakan dust aerosol and its Cl−/Na+ ratio close to seawater; (2) high Ca content in the Taklimakan dust (7.4~8.0%) which was about two times of that in the natural crust; (3) high abundance of soluble sulfate concentrations and strong correlations between sulfate and Na+ and Cl− as well as typical mineral tracers such as Al and Ca. Our results collectively indicated that the dust aerosol from the Taklimakan Desert was characterized of evident paelo-oceanic signature as the Taklimakan Desert was found as an ocean in the ancient times from the perspective of paleogeology. It was estimated that primary sources dominated the total abundances of sulfate during the dust seasons while previous climate modeling works had seldom considered the cooling effects of sulfate from the Taklimakan Desert.

Impact of mixed anthropogenic and natural emissions on air quality and eco-environment—the major water-soluble components in aerosols from northwest to offshore isle

Based on more than 300 atmospheric TSP and PM2.5 samples collected at five sites over China in 2007 and 2008, characteristics, sources, and interactions of the major water-soluble species were investigated for a better understanding of their role in urban air quality and offshore eco-environment. From the dust source regions in Northwestern China to an offshore isle over the East China Sea, concentration levels and fine/coarse particle distributions of five representative water-soluble components were well elucidated, reflecting the distinct differences of geo-history, location, and present economic situation among the target areas. NO3−/SO42− mass ratios reflected significant divergence of motorization among the studied regions. Specifically, a case study during the World Car-Free Day proved that traffic restriction measures could indeed help mitigate the aerosol species formed from vehicle emissions. Investigation on the molar concentration stoichiometry and mass percentage variations of particulate NO3−, SO42−, and NH4+ revealed that NH3 was a driving factor in the formation of major secondary water-soluble ions in atmospheric fine particles over urban areas. Based on the prevailing wind analysis, observation over an offshore isle clearly indicated the influence of the relative strength of anthropogenic sources and ocean-related natural sources on the formation and size distribution of MSA (methanesulfonic acid), a major water-soluble organic component in aerosol. Annual dry deposition flux of particulate NO3− and NH4+ over the East China Sea was estimated based on the strength of an improved calculation formula. Reductive nitrogen was found to be the major form of the deposited atmospheric inorganic nitrogen, accounting for ~ 69% of the total nitrogen depositions.