Preprints
https://doi.org/10.5194/egusphere-2022-820
https://doi.org/10.5194/egusphere-2022-820
31 Aug 2022
 | 31 Aug 2022

Experimental chemical budgets of OH, HO2 and RO2 radicals in rural air in West-Germany during the JULIAC campaign 2019

Changmin Cho, Hendrik Fuchs, Andreas Hofzumahaus, Frank Holland, William J. Bloss, Birger Bohn, Hans-Peter Dorn, Marvin Glowania, Thorsten Hohaus, Lu Liu, Paul S. Monks, Doreen Niether, Franz Rohrer, Roberto Sommariva, Zhaofeng Tan, Ralf Tillmann, Astrid Kiendler-Scharr, Andreas Wahner, and Anna Novelli

Abstract. Photochemical processes in ambient air were studied using the atmospheric simulation chamber SAPHIR at Forschungszentrum Jülich, Germany. Ambient air was continuously drawn into the chamber through a 50 m high inlet line and passed through the chamber for one month in each season throughout 2019. The residence time of the air inside the chamber was about one hour. As the research centre is surrounded by a mixed deciduous forest and is located close to the city Jülich, the sampled air was influenced by both anthropogenic and biogenic emissions. Measurements of hydroxyl (OH), hydroperoxyl (HO2) and organic peroxy (RO2) radicals were achieved by a laser-induced fluorescence instrument. The radical measurements together with measurements of OH reactivity (kOH, the inverse of the OH lifetime) and a comprehensive set of trace gas concentrations and aerosol properties allowed for the investigation of the seasonal and diurnal variation of radical production and destruction pathways. In spring and summer periods, median OH concentrations reached 6 × 106 cm-3 at noon, and median concentrations of both, HO2 and RO2 radicals, were 3 × 108 cm-3. The measured OH reactivity was between 4 and 18 s-1 in both seasons. The total reaction rate of peroxy radicals with NO was found to be consistent with production rates of odd oxygen (OX = NO2+O3) determined from NO2 and O3 concentration measurements. The chemical budgets of radicals were analysed for the spring and summer seasons, when peroxy radical concentrations were above the detection limit. For most conditions, the concentrations of radicals were mainly sustained by the regeneration of OH via reactions of HO2 and RO2 radicals with nitric oxide (NO). The median diurnal profiles of the total radical production and destruction rates showed maxima between 3 to 8 ppbv h-1 for OH, HO2 and RO2. Total ROX (OH, HO2, and RO2) initiation and termination rates were below 3 ppbv h-1. The highest OH radical turnover rate of 13 ppbv h-1 was observed during a high-temperature (max 40°C) period in August. In this period, the highest HO2, RO2 and ROX turnover rates were around 11, 10 and 4 ppbv h-1, respectively. When NO mixing ratios were between 1 ppbv to 3 ppbv, OH and HO2 production and destruction rates were balanced, but unexplained RO2 and ROX production reactions with median rates of 2 ppbv h-1 and 0.4 ppbv h-1, respectively, were required to balance their destruction. For NO mixing ratios above 3 ppbv, the peroxy radical reaction rates with NO were highly uncertain due to the low peroxy radical concentrations close to the limit of NO interferences in the HO2 and RO2 measurements. For NO mixing ratios below 1 ppbv, a missing OH source with a rate of up to 3.0 ppbv h-1 was found. This missing OH source consists likely of a combination of a missing primary radical source (0.5 ~ 1.4 ppbv h-1) and a missing inter-radical HO2 to OH conversion reaction with a rate of up to 2.5 ppbv h-1. The dataset collected in this campaign allowed to analyze the potential impact of OH regeneration from RO2 isomerization reactions from isoprene, HO2 uptake on aerosol, and RO2 production from chlorine chemistry on radical production and destruction rates. These processes were negligible for the chemical conditions encountered in this study.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.

Journal article(s) based on this preprint

08 Feb 2023
Experimental chemical budgets of OH, HO2, and RO2 radicals in rural air in western Germany during the JULIAC campaign 2019
Changmin Cho, Hendrik Fuchs, Andreas Hofzumahaus, Frank Holland, William J. Bloss, Birger Bohn, Hans-Peter Dorn, Marvin Glowania, Thorsten Hohaus, Lu Liu, Paul S. Monks, Doreen Niether, Franz Rohrer, Roberto Sommariva, Zhaofeng Tan, Ralf Tillmann, Astrid Kiendler-Scharr, Andreas Wahner, and Anna Novelli
Atmos. Chem. Phys., 23, 2003–2033, https://doi.org/10.5194/acp-23-2003-2023,https://doi.org/10.5194/acp-23-2003-2023, 2023
Short summary
Changmin Cho, Hendrik Fuchs, Andreas Hofzumahaus, Frank Holland, William J. Bloss, Birger Bohn, Hans-Peter Dorn, Marvin Glowania, Thorsten Hohaus, Lu Liu, Paul S. Monks, Doreen Niether, Franz Rohrer, Roberto Sommariva, Zhaofeng Tan, Ralf Tillmann, Astrid Kiendler-Scharr, Andreas Wahner, and Anna Novelli

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2022-820', Anonymous Referee #1, 17 Oct 2022
    • AC2: 'Reply on RC1', Changmin Cho, 09 Dec 2022
  • RC2: 'Comment on egusphere-2022-820', Anonymous Referee #2, 20 Oct 2022
    • AC3: 'Reply on RC2', Changmin Cho, 09 Dec 2022
  • AC1: 'Comment on egusphere-2022-820', Changmin Cho, 09 Dec 2022

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2022-820', Anonymous Referee #1, 17 Oct 2022
    • AC2: 'Reply on RC1', Changmin Cho, 09 Dec 2022
  • RC2: 'Comment on egusphere-2022-820', Anonymous Referee #2, 20 Oct 2022
    • AC3: 'Reply on RC2', Changmin Cho, 09 Dec 2022
  • AC1: 'Comment on egusphere-2022-820', Changmin Cho, 09 Dec 2022

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload
AR by Changmin Cho on behalf of the Authors (23 Dec 2022)  Author's response   Author's tracked changes   Manuscript 
ED: Publish as is (02 Jan 2023) by Christopher Cantrell
AR by Changmin Cho on behalf of the Authors (14 Jan 2023)  Manuscript 

Journal article(s) based on this preprint

08 Feb 2023
Experimental chemical budgets of OH, HO2, and RO2 radicals in rural air in western Germany during the JULIAC campaign 2019
Changmin Cho, Hendrik Fuchs, Andreas Hofzumahaus, Frank Holland, William J. Bloss, Birger Bohn, Hans-Peter Dorn, Marvin Glowania, Thorsten Hohaus, Lu Liu, Paul S. Monks, Doreen Niether, Franz Rohrer, Roberto Sommariva, Zhaofeng Tan, Ralf Tillmann, Astrid Kiendler-Scharr, Andreas Wahner, and Anna Novelli
Atmos. Chem. Phys., 23, 2003–2033, https://doi.org/10.5194/acp-23-2003-2023,https://doi.org/10.5194/acp-23-2003-2023, 2023
Short summary
Changmin Cho, Hendrik Fuchs, Andreas Hofzumahaus, Frank Holland, William J. Bloss, Birger Bohn, Hans-Peter Dorn, Marvin Glowania, Thorsten Hohaus, Lu Liu, Paul S. Monks, Doreen Niether, Franz Rohrer, Roberto Sommariva, Zhaofeng Tan, Ralf Tillmann, Astrid Kiendler-Scharr, Andreas Wahner, and Anna Novelli

Data sets

Data Experiments SAPHIR chamber Campaign JULIAC 2019 Cho, C., Fuchs, H., Hofzumahaus, A., Holland, F., Bohn, B., Glowania, M., Hohaus, T., Lu, L., Niehter, D., Rohrer, F., Sommariva, R., Tan, Z., Tillmann, R., Kiendler-Scharr, A., Wahner, A., and Novelli, A https://doi.org/10.26165/JUELICH-DATA/3J80BW

Changmin Cho, Hendrik Fuchs, Andreas Hofzumahaus, Frank Holland, William J. Bloss, Birger Bohn, Hans-Peter Dorn, Marvin Glowania, Thorsten Hohaus, Lu Liu, Paul S. Monks, Doreen Niether, Franz Rohrer, Roberto Sommariva, Zhaofeng Tan, Ralf Tillmann, Astrid Kiendler-Scharr, Andreas Wahner, and Anna Novelli

Viewed

Total article views: 618 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
428 174 16 618 51 3 12
  • HTML: 428
  • PDF: 174
  • XML: 16
  • Total: 618
  • Supplement: 51
  • BibTeX: 3
  • EndNote: 12
Views and downloads (calculated since 31 Aug 2022)
Cumulative views and downloads (calculated since 31 Aug 2022)

Viewed (geographical distribution)

Total article views: 595 (including HTML, PDF, and XML) Thereof 595 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 

Cited

Latest update: 19 Sep 2024
Download

The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

Short summary
With this study, we investigated the processes leading to the formation, destruction, and recycling of radicals for four seasons in a rural environment. A complete knowledge of their chemistry is needed if we are to predict the formation of secondary pollutants from primary emissions. The results highlighted an incomplete understanding of the paths leading to the formation of the OH radical and that has been observed in several different environments and that needs to be investigated further.