1,7,8,8,9- 1School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing, China (qqqzhangning@163.com)
- 2School of Environmental and Chemical Engineering, Shanghai University, Shanghai, China (qqqzhangning@163.com)
- 3College of Environment and Energy, South China University of Technology, Guangzhou, China (fengjialiang@shu.edu.cn)
- 4Shanghai Academy of Environmental Sciences, Shanghai, China (mayg@saes.sh.cn)
- 5State of Environmental Protection Key Laboratory of the Formation and Prevention of Urban Air Complex, Shanghai, China (mayg@saes.sh.cn)
- 6School of Energy and Environment, Southeast University, Nanjing, China (xinlei@seu.edu.cn)
- 7Department of Advanced Technologies in Medicine & Dentistry, University “G.d’Annunzio” of Chieti-Pescara, Chieti, Italy (piero.dicarlo@unich.it)
- 8Department of Science, University “G.d’Annunzio” of Chieti-Pescara, Chieti, Italy (piero.dicarlo@unich.it)
- 9Center for Advanced Studies and Technology-CAST, Chieti, Italy (eleonora.aruffo@unich.it)
Nitrogen-containing organic compounds (NOCs) represent key light-absorbing components of atmospheric PM2.5, yet the sources and formation mechanisms of nitrophenolic species remain unclear. Thirty-six PM2.5 samples collected during winter and summer from Yangon and Mandalay, Myanmar, were analyzed using UHPLC-Orbitrap MS. A total of 562-1318 organic compounds (average 1064) were identified in the ESI- mode, with NOCs accounting for 14-21% of molecular numbers and 13-35% of total concentrations.
Nitrophenolic compounds, defined by O/N ≥ 3 and AI > 0.5, were mainly distributed in zones C, F, and G of the Van Krevelen diagram and dominated the aromatic NOC fraction. Two ubiquitous nitrophenols—nitrocatechol (C6H5NO4) and dimethylnitrocatechol (C8H9NO4)—were detected in all samples and exhibited strong positive correlations, suggesting similar sources and transformation pathways. Their relative abundances showed distinct humidity dependence, with C6H5NO4 favored under dry conditions (RH < 50%) and C8H9NO4 under humid conditions (RH > 60%).
These findings highlight the significant role of nitrophenolic compounds in brown carbon formation and secondary processes in tropical aerosols, providing key mechanistic insights for subsequent modeling of their humidity-dependent formation pathways.
How to cite: Zhang, N., Liu, Z., Feng, J., Ma, Y., Ge, X., Wang, J., Carlo, P. D., and Aruffo, E.: Mechanisms of nitrogen-containing organic matter production in atmospheric aerosols in typical megacities in Myanmar: Coastal and Inland Cities of Yangon and Mandalay as an Example, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19929, https://doi.org/10.5194/egusphere-egu26-19929, 2026.
