Progress in high-sensitivity detection of NO3 and N2O5 in Anguang's atmosphere

[ China Instrument Network Instrument Research and Development ] Recently, the research team of Anguang Institute Xie Pinhua has made new progress in the research of simultaneous high-sensitivity detection of atmospheric NO3 and N2O5. The related research work was published in Optics Express (optical second district).

NO3 radical is the most important oxidant in the nighttime atmosphere. It can react with volatile organic compounds (VOC) to form organic nitrates. There is a thermal equilibrium relationship between N2O5 and NO3 radicals. The nighttime N2O5 hydrolysis reaction acts as an indirect loss pathway for NO3. Nitrate and ClNO2 can be formed. Secondary pollutants Organic nitrates and nitrates are important components of air pollution. In view of the key role of NO3 radicals and N2O5 in the atmospheric reaction process, accurate measurement of its concentration level and variation law is of great significance for the study of nighttime atmospheric chemistry.

On the basis of the previous research on cavity ring-down spectroscopy (CRDS), Hu Renzhi, an associate researcher, solved the problems of high-efficiency coupling of laser multi-optical path and stability control of thermal ring-down cavity, and developed a cavity capable of simultaneously measuring NO3 and N2O5. The ring-down detection system was conducted in the urban area of ​​Beijing from June 2nd to June 22nd, 2017. For the first time, this field experiment obtained the trend of NO3 free radicals and N2O5 at night in domestic urban areas. At the same time, the instrument is also applied to the measurement of the vertical profile over the winter city of Beijing. The results show that the nighttime chemical process over the winter city is still active.

The instrument can be developed to meet the needs of high-sensitivity, high-time-resolution multi-platform real-time online detection of ambient atmospheric NO3 radicals and N2O5. It can provide advanced technical means and equipment for studying atmospheric chemical processes, and further study NO3 free radicals and Data support is provided for scientific issues such as N2O5 atmospheric chemical processes and secondary pollution laws.

The research work was funded by the National Natural Science Foundation of China, the China National Institute of Ashes, and the Special Project of the Ministry of Science and Technology.

(Original title: Anguang's new progress in simultaneous high-sensitivity detection of NO3 and N2O5 in the atmosphere)