Increase of nitrooxy organosulfates in firework-related urban aerosols during Chinese New Year's Eve

Abstract

Abstract. Little is known about the formation processes of nitrooxy organosulfates (OSs) by nighttime chemistry. Here we characterize nitrooxy OSs at a molecular level in firework-related aerosols in urban Beijing during Chinese New Year. High-molecular-weight nitrooxy OSs with relatively low H / C and O / C ratios and high unsaturation are potentially aromatic-like nitrooxy OSs. They considerably increased during New Year's Eve, affected by the firework emissions. We find that large quantities of carboxylic-rich alicyclic molecules possibly formed by nighttime reactions. The sufficient abundance of aliphatic-like and aromatic-like nitrooxy OSs in firework-related aerosols demonstrates that anthropogenic volatile organic compounds are important precursors of urban secondary organic aerosols (SOAs). In addition, more than 98 % of those nitrooxy OSs are extremely low-volatility organic compounds that can easily partition into and consist in the particle phase and affect the volatility, hygroscopicity, and even toxicity of urban aerosols. Our study provides new insights into the formation of nitrooxy organosulfates from anthropogenic emissions through nighttime chemistry in the urban atmosphere.

Heterogeneous Formation of Organonitrates (ON) and Nitroxy-Organosulfates (NOS) from Adsorbed α-Pinene-Derived Organosulfates (OS) on Mineral Surfaces

“…Duportéet al observed an OS at 249 (compound 5 in this study) dehydrating to an OS at 231 (compound 6) during MS analysis. 27 On kaolinite, α-pinene derivatives pinonaldehyde (11) and pinonaldehyde dimer (12) are formed 40 and further oxidized to form their respective acids (compounds 13 and 14). Formation of pinonaldehyde and pinonaldehyde dimer upon exposure to kaolinite surfaces is explained in detail in our previous study.…”

“…Primary biogenic precursors are isoprenes, monoterpenes, sesquiterpenes, and aldehydes. 11 α-Pinene (C 10 H 16 ), a biogenic volatile organic compound, is one of the most abundant atmospheric monoterpenes with an average estimated emission of 66 Tg yr −1 . 12−15 Furthermore, α-pinene-derived OS-, ON-, and NOS-SOA along with oxygenated α-pinene derivatives have been detected in ambient air.…”

“…42 Increased NOS formation due to fireworks has also been previously observed. 11 However, formation pathways for NOS, in general, are less well understood, although their relative abundance and formation pathways involving heterogeneous chemistry in nighttime conditions remain scarce. In this study, reactions of NO 2 and HNO 3 with α-pinene-OS adsorbed on mineral surfaces hematite (α-Fe 2 O 3 ) and kaolinite (SiO 2 Al 2 O 3 (OH) 4 ) were studied.…”

Deciphering 13C and 34S Isotopes of Organosulfates in Urban Aerosols by FT-ICR Mass Spectrometry

“…Here, we seek to S4. 54 identify a series of 13 C and 34 S isotopes of OSs and to estimate their corresponding δ 13 C and δ 34 S values at the molecular level in urban aerosols using FT-ICR MS. The 34 S isotopes of aliphatic and non-aliphatic OSs were separated to investigate their precursors and potential formation pathway.…”

“…(b−d) Molecular weight and DBE distribution, typical Van Krevelen plots, and molecular corridors and volatility of 13 C and 34 S isotopes of OSs during the heavy-haze period, respectively. The classification criteria for panel c are listed in TableS4 54.…”