Recently, the "Spontaneous/Simulated Raman and Rayleigh Scattering Combined Device" project applied by Professor Zhang Yunhong from the School of Chemistry and Chemical Engineering of Beijing Institute of Technology received funding from the National Natural Science Foundation of China for the major instrument development project (Project Approval Number: 42127806, funding amount: 5,983,300 yuan), the project was led by Beijing Institute of Technology, and Jiangsu Ocean University and CIS-Systems (Beijing) Technology Co., Ltd. participated in the application.

The research team of Professor Zhang Yunhong from the Institute of Physical Chemistry, School of Chemistry and Chemical Engineering, has been conducting long-term research on the formation and evolution mechanism of atmospheric fine particles (PM2.5), and has formed its characteristics and advantages in the in-situ Raman spectroscopy study of suspended aerosol single particles.

One of the main objectives of ecological civilization construction and ecological environment protection during the "14th Five Year Plan" period is to deeply fight the blue sky defense war, continue to significantly reduce the concentration of PM2.5 and eliminate heavily polluted weather. In recent years, China has achieved remarkable results in the control of atmospheric particulate matter pollution, and the annual average PM2.5 concentration in cities has been significantly reduced. However, there is still a big gap from the World Health Organization guidance value (5μg /m3), which makes it more difficult to further control. This requires a clear understanding of the deeper formation mechanism of atmospheric haze, and the establishment of precise research methods for the physical and chemical processes of aerosols at the single particle level.

The formation mechanism of PM2.5 is a world problem. The key scientific problem is to accurately measure the physical and chemical parameters of fine particles during the evolution process, which poses new challenges for spectroscopy measurement. This major instrument project uses electric suspension, optical suspension, acousto-optic deflection control suspension and other technologies to capture, suspend, and control single droplets and multiple droplets, and establish an in-situ measurement device for suspended droplets with time and space resolution functions. The combination of spontaneous, stimulated Raman and Rayleigh scattering can provide in-situ spectral information of the dynamic process of chemical composition changes inside, on the surface and in the gas phase of the droplet, and it can accurately measure the saturated vapor pressure, growth factor, diffusion coefficient, refractive index and the uptake coefficient of the reaction with trace gases such as SO2, NOx and O3; through the spatially resolved observation of the liquid-liquid phase separation process, the change information of the chemical composition evolution of different liquid phases is obtained; through suspension control of multiple droplets with the same or different composition, the Raman spectra of multiple droplets can be measured at the same time, and the Raman spectra of collision, fusion and reaction processes between droplets can be observed in situ. This major instrument project can provide favorable measurement methods for the study of low- and medium-level haze pollution mechanisms, and provide support for formulating effective PM2.5 emission reduction policies and assessing the climate and health effects of PM2.5.

Professor Zhang Yunhong obtained his Ph.D. in Chemistry from Jilin University in 1991. He joined Beijing Institute of Technology in 1995 and was named a professor in 1998. He won the Fok Yingdong Excellent Teacher Fund and was selected into the cross-century talent training program of the Ministry of Education. Over the years, he has been committed to the research of atmospheric aerosol physical and chemical processes closely related to environmental issues, and completed 2 key projects of the National Natural Science Foundation of China and 7 general projects.