TY - JOUR
T1 - Chlorine oxidation of VOCs at a semi-rural site in Beijing
T2 - Significant chlorine liberation from ClNO2 and subsequent gas- A nd particle-phase Cl-VOC production
AU - Le Breton, Michael
AU - Hallquist, Åsa M.
AU - Kant Pathak, Ravi
AU - Simpson, David
AU - Wang, Yujue
AU - Johansson, John
AU - Zheng, Jing
AU - Yang, Yudong
AU - Shang, Dongjie
AU - Wang, Haichao
AU - Liu, Qianyun
AU - Chan, Chak
AU - Wang, Tao
AU - Bannan, Thomas J.
AU - Priestley, Michael
AU - Percival, Carl J.
AU - Shallcross, Dudley E.
AU - Lu, Keding
AU - Guo, Song
AU - Hu, Min
AU - Hallquist, Mattias
PY - 2018/9/11
Y1 - 2018/9/11
N2 - 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 N2O5 and a suite of inorganic halogens including ClNO2 and 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 ClNO2 was 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-3 from ClNO2 alone, peaking at 09:30LT and up to 8.4 × 105moleculescm-3 when 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.
AB - 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 N2O5 and a suite of inorganic halogens including ClNO2 and 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 ClNO2 was 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-3 from ClNO2 alone, peaking at 09:30LT and up to 8.4 × 105moleculescm-3 when 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.
UR - http://www.scopus.com/inward/record.url?scp=85049773150&partnerID=8YFLogxK
U2 - 10.5194/acp-18-13013-2018
DO - 10.5194/acp-18-13013-2018
M3 - Journal article
AN - SCOPUS:85049773150
SN - 1680-7316
VL - 18
SP - 13013
EP - 13030
JO - Atmospheric Chemistry and Physics
JF - Atmospheric Chemistry and Physics
IS - 17
ER -