EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

In situ measurement for tropospheric OH radical by Laser Induced Fluorescence technique during STORM campaign

Fengyang Wang1,2, Renzhi Hu1, Pinhua Xie1,2, Yihui Wang1,2, Shengrong Lou3, Keding Lu4, Guoxian Zhang1,2, Jianguo Liu1,2, and Wenqing Liu1,2
Fengyang Wang et al.
  • 1Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China (
  • 2University of Science and Technology of China. Hefei 230031, China
  • 3State Environmental Protection Key Laboratory of Formation and Prevention of the Urban Air Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233, China
  • 4State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China

Hydroxyl (OH) play an essential role in atmospheric chemistry. OH radical is an indicator of atmospheric oxidation and self-purification, which determines the removal of most trace gases in the atmosphere, such as CO, SO2, NO2, CH4 and other volatile organic compounds (VOCs). A ground-based system for measurement of tropospheric OH radical by Laser Induced Fluorescence technique (AIOFM-LIF) was developed and integrated into a mobile observation platform for field observation. Ambient air expands through a 0.4 mm nozzle to low pressure. OH radical is irradiated by the 308 nm laser pulse at a repetition rate of 8.5 kHz, accompanying the release fluorescence of the A2Σ+(v’=0)—X2Πi(v’’=0) transition at 308 nm with the resultant fluorescence being detected by gated photon counting. The detection sensitivity of AIOFM-LIF system was calibrated by a portable standard OH radical source based on water photolysis-ozone actinometry. Following laboratory and field calibrations to characterise the instrument sensitivity, OH radical detection limits were (1.84±0.26) × 105 cm-3 and (3.69±0.52) × 105 cm-3 at night and noon, respectively. During “A comprehensive STudy of the Ozone foRmation Mechanism in Shenzhen” (STORM) campaign, AIOFM-LIF system was deployed in Shenzhen, China, and OH radical concentration was obtained validly except for the rainy days. Mean diurnal variation of HOx radical concentration was obtained, and the peak was 6.6×106 cm-3 which appeared around 12:00 at noon. A general good agreement of OH radical concentration with j(O1D) was observed with a high correlation (R2 =0.77), which illustrates that photolysis of ozone is an important source of OH radical during this campaign. A box model was applied to simulate the concentrations of OH at this field site, the primary production of OH radical was generally dominated by photolysis of O3, HONO, HCHO, while the other production was contributed by calculated species (OVOCs).

How to cite: Wang, F., Hu, R., Xie, P., Wang, Y., Lou, S., Lu, K., Zhang, G., Liu, J., and Liu, W.: In situ measurement for tropospheric OH radical by Laser Induced Fluorescence technique during STORM campaign, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12047,, 2020