Production of N<sub>2</sub>O<sub>5</sub> and ClNO<sub>2</sub> in summer in urban Beijing, China

Abstract

Abstract. The heterogeneous hydrolysis of dinitrogen pentoxide (N 2 O 5 ) has a significant impact on both nocturnal particulate nitrate formation and photochemistry on the following day through the photolysis of nitryl chloride (ClNO 2 ), yet these processes in highly polluted urban areas remain poorly understood. Here we present measurements of gas-phase Further analysis indicates that the fast N 2 O 5 loss in the nocturnal boundary layer in urban Beijing is mainly attributed to its indirect loss via NO 3 , for example through the reactions with volatile organic compounds and NO, while the contribution of the heterogeneous uptake of N 2 O 5 is comparably small (7-33 %). High ClNO 2 yields ranging from 0.10 to 0.35 were also observed, which might have important implications for air quality by affecting nitrate and ozone formation.

Hygroscopic Properties of Saline Mineral Dust From Different Regions in China: Geographical Variations, Compositional Dependence, and Atmospheric Implications

“…Significant production of ClNO 2 , in addition to N 2 O 5 uptake, was observed, indicating that saline mineral dust particles could be an important source for chlorine species (e.g., ClNO 2 ) in continental North America (Mitroo et al, 2019). Our present work showed that the amounts of chloride could be substantial for saline mineral dust particles collected in northern China, where high levels of N 2 O 5 up to several parts per billion by volume were observed Wang et al, 2018;Zhou et al, 2018). Therefore, heterogeneous reactions of saline mineral dust particles can be an important source for the observed ClNO 2 in north China.…”

Shipborne measurements of ClNO<sub>2</sub> in the Mediterranean Sea and around the Arabian Peninsula during summer

“…The release of HCl through acid displacement leads to a deficit in particulate Cl − concentrations which can be expressed in terms of a chloride depletion factor (Eq. 12), where Na + and Cl − represent the concentrations in moles per cubic metre and 1.174 is the molar ratio of Cl − to Na + found in seawater (Zhuang et al, 1999).…”

Intercomparison of nitrous acid (HONO) measurement techniques in a megacity (Beijing)

“…As a result of the significance of HONO to tropospheric photochemistry, accurate and precise concentration measurements are required but are challenging due to a number of known potential artefacts in the available approaches. Positive artefacts can occur in inlet lines, as HONO is easily formed through heterogeneous reactions on wet surfaces (Zhou et al, 2002). Furthermore, the highly reactive nature of HONO means that within inlet lines, wall interactions could also lead to a negative artefact unless inert materials are employed (Pinto et al, 2014).…”