Heterogeneous uptake of NO2 by sodium acetate droplets and secondary nitrite aerosol formation

Wen Xiu Pei, Shuai Shuai Ma, Zhe Chen, Yue Zhu, Shu Feng Pang*, Yun Hong Zhang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

The high NO3 concentration in fine particulate matters (PM2.5) during heavy haze events has attracted much attention, but the formation mechanism of nitrates remains largely uncertain, especially concerning heterogeneous uptake of NOX by aqueous phase. In this work, the heterogeneous uptake of NO2 by sodium acetate (NaAc) droplets with different NO2 concentrations and relative humidity (RH) conditions is investigated by microscopic Fourier transform infrared spectrometer (micro-FTIR). The IR feature changes of aqueous droplets indicate the acetate depletion and nitrite formation in humid environment. This implies that acetate droplets can provide the alkaline aqueous circumstances caused by acetate hydrolysis and acetic acid (HAc) volatilization for nitrite formation during the NO2 heterogeneous uptake. Meanwhile, the nitrite formation will exhibit a pH neutralizing effect on acetate hydrolysis, further facilitating HAc volatilization and acetate depletion. The heterogeneous uptake coefficient increases from 5.2 × 10−6 to 1.27 × 10−5 as RH decreases from 90% to 60% due to the enhanced HAc volatilization. Furthermore, no obvious change in uptake coefficient with different NO2 concentrations is observed. This work may provide a new pathway for atmospheric nitrogen cycling and secondary nitrite aerosol formation.

Original languageEnglish
Pages (from-to)320-327
Number of pages8
JournalJournal of Environmental Sciences (China)
Volume127
DOIs
Publication statusPublished - May 2023

Keywords

  • Heterogeneous uptake
  • NaAc droplets
  • Nitrite
  • Uptake coefficient

Fingerprint

Dive into the research topics of 'Heterogeneous uptake of NO2 by sodium acetate droplets and secondary nitrite aerosol formation'. Together they form a unique fingerprint.

Cite this