This research area focuses on the composition, concentration, temporal-spatial distribution and multi-phase reactions of atmospheric trace gases and aerosols. The results will be helpful to understand the natural cycle as well as the regional or global climate changes, acid rain formation, ozonosphere destruction and marine environmental changes. Since this area has been emphasized in the past twenty years, an integrated research team on atmospheric chemistry has been established, with state-of-the-art facilities and unique scientific approach.
Researchers in this area have been supported by 9 grants from National Natural Science Foundation of China, 2 grants from Sub-program of Major Program of the National Natural Science Foundation of China, 2 grants from Ph.D. Programs Foundation of Ministry of Education of China, the “Dawn” Program of Shanghai Education Commission, and the Memorial Foundation for World Exposition in Japan. We have published over 140 papers in peer review scientific journals including many high quality international journals, such as Environ. Sci. Technol., Atm. Environ, JGR, Chinese Science Bulletin and Science in China. Our researches are of great importance for control and treatment of atmospheric pollution, urban development, planning and administration, developing strategy on global changes, environmental diplomacy and even future strategy establishment of the nation.
1. Multi-phase reaction of atmospheric aerosols in global environmental change. Atmospheric aerosol study is one of the most active branches and the frontier of current international atmospheric chemistry. In our department, research in this track focused on multi-phase reaction kinetics, reaction mechanism and species change on particle surface. We have successfully obtained the kinetic rates of multi-phase reactions of atmospheric particles and typical oxides (SiO2, Al2O3, CaO, MgO, Fe2O3) with CS2, COS, DMS and SO2 and the adsorption constants by combining DRIFTS and FTIR-long term white cell, and found the multi-phase reaction of CS2 and atmospheric particle is a catalytic oxidation based on the adsorbed oxygen on particle surface (Environ. Sci. Technol., 2001). It was concluded that multi-phase reaction might be an important source of global COS, which received great responses in the domestic and international academic field (Journal of Fudan University (Natural Sciences), 2002; Chinese Science Bulletin, 2004; Science in China (Series B), 2004).
2. Methods and technology of atmospheric trace gases observation and measurement; the influence of atmospheric trace gases on atmospheric environment. We have made prominent discoveries in studies on the temporal-spatial changes of atmospheric super-trace gases (CFCs and O3) and dynamic changes of super-trace gases (South Pole) damaging ozone layer (Environ. Anal. Chem，2002；Environ. Sci. Technol., 2001). A new techniques was invented by our department to improve the ECD sensitivity and studied the mechanism due to the concentration of CFCs is low. We also cooperate with Gothenburg /Chalmers University in Sweden and Heidelberg University in Germany on developing “New Differential Optical Absorption Spectroscopy” and detected CS2 in Shanghai for the first time with the instrument (JGR, 2004).
3. Free radical chemistry and photochemistry of atmospheric pollutants. In this area, our department works on the global environment issues, such as, the photochemistry of substances destructing ozone layer, chemistry of plasma, source and sink of sulfur compound and new greenhouse gas SF5CF3, and regional environment issues, such as, the mechanism and preventions of photochemical smog in Shanghai. Nanosecond Laser Transient Spectrum Technology enables the representation of transient species and promotes the research in this area greatly. We are studying the conversion reaction of organic pollutants inside or outside the atmospheric liquid-phase and crystal ice with this technology.
4. Impact of aerosols in China on regional environment and global biological and geochemical circles. We monitored continuously for years on the monitor sites all over the country, obtained more than ten thousand samples, and study the source, distribution, conversion and physical and chemical properties of sand storm in China. Our observation proved that the increased pollutants in the sand storm are mainly come from secondary blowing dust, sulfate and organic aerosols from multi-phase reactions in the areas where sand storm pass through. Sand storms transport not only trace pollutants ten times higher than ordinary aerosols, but also Fe (II) much higher than normal aerosols and unreduced Fe (III) ten times higher than normal aerosols during their long term transfer. The concentrations of SO42- and Fe (II) are positively correlative, which further prove the Fe-S coupling mechanism in the long term transportation of aerosols. We developed a new graph analysis technique for single particle (X-Y graph and triple graph), which vividly elucidates the internal mixture (infiltration into substances) or external mixture (mixing between substances) of mineral aerosol and pollutant aerosol in aerosol particles of sand storm, and gradual replacement among mineral aerosol components during long distance transportation.