ES&T视角: 中国应加强室内空气(光)化学与健康研究

Sasho 研究员

Sasho Gligorovski, a research professor in Guangzhou Institute of Geochemistry of CAS,  suggests that advancing the scientific knowledge on indoor (photo)chemistry and resulting health effects in the coming years in China, requires stronger interactions between atmospheric chemists/physicists, and scientists from the fields of toxicology, epidemiology, and medicine.

In this viewpoint, the latest exciting findings on the HONO formation processes and OH radical production through photolysis of HONO have been reviewed and commented. For a long time, the contribution of HONO photolysis to indoor OH radicals has been overlooked and, the indoor levels of OH radicals and the resulting health impact are very likely underestimated, especially within a short time-frame or a small confined space. In China, the concentrations of indoor pollutants are 100 to 1000 times higher than that inside European and US homes, not to mention 3.1 million deaths in rural China caused by indoor air pollution every year. However, our knowledge on the processes related to OH radical formation in the indoor environments of Chines dwellings is very limited, which makes it becomes an urgent need to take actions from now on. The authors believe that, by taking full consideration of real-life indoor scenarios in China (e.g., coal burning for heating in the North China, cooking) and with the assistance of advanced experimental and analytical techniques lately emerged, comprehensive understanding on the indoor photochemistry and resulting health impact in China indoor environments is attainable in the near future.

Just as the outdoor atmospheric chemistry community has focused in recent years on developing an understanding of specific topics, such as haze and PM2.5, it is just now starting to address the photochemistry in the environment in which we live 90% of our time.

In this manner this viewpoint informs the readers of research questions of direct relevance to their lives. It also points out that this complex chemistry will become even more important as we live more and more of our lives indoors, i.e. increased indoor exposure will arise as Chinese society rapidly industrialize.

Fo r more informtaion, please see:  S. Gligorovski, X. Li, H. Herrmann, Indoor (Photo)chemistry in China and Resulting Health Effects, Environ. Sci. Technol., 2018, 52, 10909–10910.

ES&T: 离子强度影响臭氧(O3)在大气-海洋界面的反应性沉降速率

Majda Mekic, a PhD student of Professor Sasho Gligorovski in SKLOG, Guangzhou Institute of Geochemistry of CAS, published an article in Environmental Science and Technology focused on ionic strength effects on reactive uptakes of ozone on aqueous pyruvic acid.

The ionic strength can affect the kinetics and products distribution within the aerosol deliquescent particles and at the sea surface microlayer. However, the ionic strength effects on aqueous phase reactions of atmospheric relevance have been barely studied in the past. In this work, Mekic et al. have leveraged our knowledge on ionic strength effects on the reactive uptakes of gas-phase ozone on aqueous pyruvic acid by the well-known wetted wall flow tube technique.

Fig 1 Uptake coefficients of ozone (100 ppb) as a function of the Br- concentration.

A relatively weak dependence was observed between the uptake coefficients of O3 and the concentration of Br- in the absence of pyruvic acid. The uptake coefficients of ozone increased markedly at elevated bromide concentrations in presence of pyruvic acid. This finding clearly indicates that the dry deposition of ozone to the sea surface could be significantly enhanced by carbonyl compounds (e.g., pyruvic acid) that occur at the bromide-rich sea surface microlayer.

Based on the observed uptake coefficients, the estimated deposition velocity of ozone for nM-range PA concentrations is 9.7 · 10-4 m s-1, in the same order as the upper-limit ozone deposition velocity due to the ozone reaction with chlorophyll (1 · 10-5 m s-1 to 1 · 10-3 m s-1), and higher than the deposition velocity of 1.2 · 10-4 m s-1 assessed for the reaction of ozone with a mixture of DOM and iodide. Therefore, the surface reaction between ozone and PA makes an important contribution to the ozone deposition velocity on the ocean surface.

Sasho 研究员

The formation of oligomeric species during the heterogeneous reaction of ozone with pyruvic acid in dilute aqueous phase by the means of Ultrahigh-Resolution Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry, was assessed as well. A comparison between the previous results and the present ones suggests that the products formed from the reaction of O3 with pyruvic acid at the water surface (at low ionic strength, which under environmental conditions could be the surface of cloud droplets and aerosol deliquescent particles), either in the dark or under irradiation exhibit much more complex structure than the products formed upon photolytic degradation of pyruvic acid in the bulk aqueous phase.

For more information, please see: M. Mekic, G. Loisel, W. Zhou, B. Jiang, D. Vione, S. Gligorovski, Ionic strength effects on the reactive uptake of ozone on aqueous pyruvic acid: Implications for air-sea ozone deposition, Environ. Sci. Technol., 2018, DOI: 10.1021/acs.est.8b03196.

OG:松辽盆地晚白垩世海侵事件与优质烃源岩发育

胡建芳 研究员

松辽盆地嫩江组二段发育了大量优质烃源岩,前人研究认为嫩江组二段富有机质烃源岩沉积于淡水、富营养化的水体环境。高的生物生产力是烃源岩形成的主控因素。但越来越多的证据表明,嫩江组二段下部发生过海侵事件。海侵事件对烃源岩的发育有怎样的影响?这一问题,目前还缺乏系统研究。

近期,中科院广州地球化学研究所有机地球化学国家重点实验室童晓宁博士及导师胡建芳研究员,以松辽盆地东南部岳王城露头剖面为研究对象,开展了系统的有机地球化学研究,试图探讨松辽盆地嫩江组二段烃源岩形成时期的水体环境。结果发现其烷烃组成以中低碳数烷烃为主,且δ13Corg为-30.2‰~-28.0‰,表明嫩江组二段下部有机质主要来源于藻类、大型水生植物,少量来源于细菌和陆地高等植物。特征生物标志物的剖面变化特征显示出嫩江组二段下部水体环境经历了3个演化阶段(图1,图2,图3):

其中,阶段I湖泊下部水体缺氧,且缺氧状况甚至扩展至透光带。24-正丙基胆甾烷和24-异丙基胆甾烷分别来源于海相金藻和海绵,是特征海相生物标志物。高含量的C30甾烷揭示出阶段I发生了强烈的海侵事件(图2)。阶段II 海侵的规模减弱,相应地水体的缺氧程度减弱;阶段III 伴随着海侵规模的进一步减弱,湖泊水体由缺氧转化为氧化环境,只在沉积界面缺氧。此外,脱羟基维生素E相关比值(MTTCI 和 MTTC α/γ)还显示嫩江组二段下部为半咸水–咸水的水体环境(图1,图3)。

海水的侵入,使得湖泊水体产生盐度分层,同时湖泊内藻类的勃发加快了湖泊水体氧化/还原分层,这样的沉积环境十分有利于有机质的保存。嫩江组二段油页岩形成时期与湖泊水体盐度分层、缺氧的沉积环境以及海侵事件发生阶段高度吻合,揭示出海侵的发生与高盐、缺氧、分层的水体环境及油页岩的形成密切相关。

图1. 嫩江组二段下部Pr/Ph、 A-i/P、the Gammacerane Index、MTTCI (α-MTTC/ total MTTCs)和 MTTC α/γ 比值的剖面变化特征

图2.  嫩江组二段下部24-正丙基胆甾烷和24-异丙基胆甾烷的剖面变化特征

图3. 松辽盆地嫩二段优质烃源岩发育阶段湖泊水体演化的3个阶段

该项成果得到国家自然科学基金面上项目资助,相关成果发表在《Organic Geochemistry》上。

Tong, X., Hu, J., Xi, D., Zhu, M., Song, J., Peng, P., 2018. Depositional environment of the Late Santonian lacustrine source rocks in the Songliao Basin (NE China): Implications from organic geochemical analyses. Organic Geochemistry, 124, 215–227.

原文链接:https://doi.org/10.1016/j.orggeochem.2018.07.018