This book systematically describes the instrument setup for the measurement of nitrate radical (NO3) and dinitrogen pentoxide (N2O5), as well as the mixing ratio, chemical behaviors, and atmospheric impacts of NO3 and N2O5 in Beijing, China. It also discusses the instrument design and data analysis method in detail. Based on several field measurements of NO3 and N2O5 in Beijing, it shows the variation in concentration and the budget of NO3 and N2O5. The N2O5 heterogeneous uptake coefficient was determined using various methods, and the relationship between the N2O5 uptake coefficient and the particle properties was demonstrated, as well as the impact of NO3-N2O5 chemistry to the atmospheric oxidation and the formation of particulate nitrate. These results increase our understanding of nighttime chemistry and provide insights into the role of NO3-N2O5 chemistry in other polluted regions.

Dr. Haichao Wang received a Ph.D. in environmental science at Peking University (PKU) in 2018. Now he is an Associate Professor at Sun Yat-sen University. His research interests include the development of high sensitivity optical instrumentation for laboratory and field studies of atmospheric trace gases (e.g., NO3, N2O5), and the chemical behaviors and impacts of reactive nitrogen species in the atmosphere. He has published more than 20 research papers in this area. He won the President Scholarship for Ph.D. Students of PKU in 2016-2018, and the Qian Yi Environment Award in 2017. His Ph.D. thesis was selected as the outstanding doctor degree dissertations in PKU in 2018, and he won the excellent post-doctor in PKU during 2018-2020.