Skip to main content
U.S. flag

An official website of the United States government

Dot Gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

HTTPS

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Impacts of Heterogeneous Uptake of Dinitrogen Pentoxide and Chlorine Activation On Ozone and Reactive Nitrogen Partitioning: Improvement and Application of The WRF-CHEM Model In Southern China

Abstract

The uptake of dinitrogen pentoxide (N2O5) on aerosol surfaces and the subsequent production of nitryl chloride (ClNO2) can have a significant impact on the oxidising capability and thus on secondary pollutants such as ozone. The range of such an impact, however, has not been well quantified in different geographical regions. In this study, we applied the Weather Research and Forecasting coupled with Chemistry (WRF-Chem) model to investigate the impact of the N2O5 uptake processes in the Hong Kong–Pearl River Delta (HK–PRD) region, where the highest ever reported N2O5 and ClNO2 concentrations were observed in our recent field study. We first incorporated into the WRF-Chem an aerosol thermodynamics model (ISORROPIA II), recent parameterisations for N2O5 heterogeneous uptake and ClNO2 production and gas-phase chlorine chemistry. The revised model was then used to simulate the spatiotemporal distribution of N2O5 and ClNO2 over the HK–PRD region and the impact of N2O5 uptake and Cl activation on ozone and reactive nitrogen in the planetary boundary layer (PBL). The updated model can generally capture the temporal variation of N2O5 and ClNO2 observed at a mountaintop site in Hong Kong, but it overestimates N2O5 uptake and ClNO2 production. The model results suggest that under average conditions, elevated levels of ClNO2 (>0.25ppb within the PBL) are present in the south-western PRD, with the highest values (>1.00ppb) predicted near the ground surface (0–200m above ground level; a.g.l.). In contrast, during the night when very high levels of ClNO2 and N2O5 were measured in well-processed plumes from the PRD, ClNO2 is mostly concentrated within the residual layer (???300ma.g.l.). The addition of N2O5 heterogeneous uptake and Cl activation reduces the NO and NO2 levels by as much as 1.93ppb (???7.4%) and 4.73ppb (???16.2%), respectively, and it increases the total nitrate and ozone concentrations by up to 13.45µgm?3 (???57.4%) and 7.23ppb (???16.3%), respectively, in the PBL. Sensitivity tests show that the simulated chloride and ClNO2 concentrations are highly sensitive to chlorine emission. Our study suggests the need to measure the vertical profiles of N2O5?ClNO2 under various meteorological conditions, to consider the chemistry of N2O5?ClNO2 in the chemical transport model and to develop an updated chlorine emission inventory over China.

Article / Publication Data
Active/Online
YES
Volume
16
Available Metadata
Accepted On
October 23, 2016
DOI ↗
Fiscal Year
Peer Reviewed
YES
Publication Name
Atmospheric Chemistry and Physics
Published On
December 01, 2016
Publisher Name
European Geophysical Union
Print Volume
16
Print Number
23
Page Range
14875-14890
Submitted On
May 16, 2016
URL ↗

Institutions

Not available

Authors

Authors who have authored or contributed to this publication.

  • Qinyi Li - lead None
    Other
  • Li (Kate) Zhang - second Gsl
    Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder
    NOAA/Global Systems Laboratory
  • Ravan Ahmadov - fifth Gsl
    Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder
    NOAA/Global Systems Laboratory