Chlorine oxidation of VOCs at a semi-rural site in Beijing: Significant chlorine liberation from ClNO2 and subsequent gas- A nd particle-phase Cl-VOC production
Artikel i vetenskaplig tidskrift, 2018

Nitryl chloride (ClNO2) accumulation at night acts as a significant reservoir for active chlorine and impacts the following day's photochemistry when the chlorine atom is liberated at sunrise. Here, we report simultaneous measurements of N2O5and a suite of inorganic halogens including ClNO2and reactions of chloride with volatile organic compounds (Cl-VOCs) in the gas and particle phases utilising the Filter Inlet for Gas and AEROsols time-of-flight chemical ionisation mass spectrometer (FIGAERO-ToF-CIMS) during an intensive measurement campaign 40km northwest of Beijing in May and June 2016. A maximum mixing ratio of 2900ppt of ClNO2was observed with a mean campaign nighttime mixing ratio of 487ppt, appearing to have an anthropogenic source supported by correlation with SO2, CO and benzene, which often persisted at high levels after sunrise until midday. This was attributed to such high mixing ratios persisting after numerous e-folding times of the photolytic lifetime enabling the chlorine atom production to reach 2.3 × 105moleculescm-3from ClNO2alone, peaking at 09:30LT and up to 8.4 × 105moleculescm-3when including the supporting inorganic halogen measurements. Cl-VOCs were observed in the particle and gas phases for the first time at high time resolution and illustrate how the iodide ToF-CIMS can detect unique markers of chlorine atom chemistry in ambient air from both biogenic and anthropogenic sources. Their presence and abundance can be explained via time series of their measured and steady-state calculated precursors, enabling the assessment of competing OH and chlorine atom oxidation via measurements of products from both of these mechanisms and their relative contribution to secondary organic aerosol (SOA) formation.


Michael Le Breton

Göteborgs universitet

Åsa M. Hallquist

IVL Svenska Miljöinstitutet

Ravi Kant Pathak

Göteborgs universitet

David Simpson

Chalmers, Rymd-, geo- och miljövetenskap, Mikrovågs- och optisk fjärranalys

Meteorologisk institutt

Yujue Wang

Beijing University of Technology

John Johansson

Chalmers, Rymd-, geo- och miljövetenskap, Mikrovågs- och optisk fjärranalys

Jing Zheng

Beijing University of Technology

Yudong Yang

Beijing University of Technology

Dongjie Shang

Beijing University of Technology

Haichao Wang

Beijing University of Technology

Qianyun Liu

Hong Kong University of Science and Technology

Chak Chan

City University of Hong Kong

Tao Wang

Hong Kong Polytechnic University

Thomas J. Bannan

University of Manchester

Michael Priestley

University of Manchester

C. J. Percival

Jet Propulsion Laboratory, California Institute of Technology

University of Manchester

Dudley E. Shallcross

University of the Western Cape

University of Bristol

Keding Lu

Beijing University of Technology

Song Guo

Beijing University of Technology

Min Hu

Beijing University of Technology

Mattias Hallquist

Göteborgs universitet

Atmospheric Chemistry and Physics

1680-7316 (ISSN) 1680-7324 (eISSN)

Vol. 18 17 13013-13030


Meteorologi och atmosfärforskning

Atom- och molekylfysik och optik

Annan kemi



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