EXHALE Project

EXHALE (EXploiting new understanding of Heterogeneous production of reactive species from AIRPRO: Links to haze and human health Effects) project

About the project:

Recent fieldwork in central Beijing in 2016/17 found that pollutant chemistry is more complex than expected, particularly during haze events when loadings of particulate matter were high and large concentrations of the hydroxyl radical (OH) were observed. Nitrous acid (HONO) was found to be the dominant OH precursor in Beijing, however detailed models are unable to fully account for levels of HONO, OH and other radicals, especially during the polluted haze events. EXHALE will quantify heterogeneous sources of nitrous acid (HONO) and other reactive species from aerosol surfaces using particulate matter (PM) collected on filters from Beijing ambient aerosol, and using model aerosols. The filter samples will be analysed off-line by a variety of analytical methods to determine the composition of the PM, and an extract used to generate aerosols in the laboratory in Leeds, with HONO and radical production rates determined using an illuminated aerosol flow-tube apparatus equipped with sensitive detectors. The production rates will be determined as a function of atmospheric variables and parameterisations used in a box model with the detailed Master Chemical Mechanism and in a large-scale regional model using WRF-Chem for Beijing and other mega-cities across China. The large scale implications of heterogeneous processes towards regional episodes of ozone and secondary organic aerosol will be quantified.

Team:

  • Dr Stephen Arnold, Associate Professor of Atmospheric Composition, School of Earth and the Environment, University of Leeds.
  • Dr Lauren Fleming, Research Fellow, School of Chemistry, University of Leeds.
  • Prof Dwayne Heard, Professor of Atmospheric Chemistry, University of Leeds.
  • Dr Keding Lu, Assistant Professor at the State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Science and Engineering, Peking University.
  • Prof Dominick Spracklen, Professor of Biosphere-Atmosphere Interactions, School of Earth and the Environment, University of Leeds.
  • Dr Lisa Whalley, NCAS Senior Research Fellow, School of Chemistry, University of Leeds.
  • Dr Chunxiang (Jack) Ye, Assistant Professor at the State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Science and Engineering, Peking University.
  • Professor Tong Zhu, Dean and Cheung Kong Chair Professor, College of Environmental Sciences and Engineering, Peking University.