Universität zu Köln

Pang, Jacky Yat Sing, Novelli, Anna ORCID: 0000-0003-2077-7573, Kaminski, Martin, Acir, Ismail-Hakki, Bohn, Birger ORCID: 0000-0003-4177-3934, Carlsson, Philip T. M., Cho, Changmin, Dorn, Hans-Peter, Hofzumahaus, Andreas, Li, Xin, Lutz, Anna, Nehr, Sascha ORCID: 0000-0002-1882-3625, Reimer, David, Rohrer, Franz, Tillmann, Ralf ORCID: 0000-0003-0648-6622, Wegener, Robert, Kiendler-Scharr, Astrid, Wahner, Andreas and Fuchs, Hendrik ORCID: 0000-0003-1263-0061 (2022). Investigation of the limonene photooxidation by OH at different NO concentrations in the atmospheric simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber). Atmos. Chem. Phys., 22 (13). S. 8497 - 8528. GOTTINGEN: COPERNICUS GESELLSCHAFT MBH. ISSN 1680-7324

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Abstract

The oxidation of limonene by the hydroxyl (OH) radical and ozone (O-3) was investigated in the atmospheric simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) in experiments performed at different nitric oxide (NO) mixing ratios from nearly 0 up to 10 ppbv. For the experiments dominated by OH oxidation, the formaldehyde (HCHO) yield was experimentally determined and found to be (12 +/- 3), (13 +/- 3), and (32 +/- 5) % for experiments with low (similar to 0.1 ppbv), medium (similar to 0.3 ppbv), and high NO (5 to 10 ppbv), respectively. The yield in an ozonolysis-only experiment was (10 +/- 1) %, which agrees with previous laboratory studies. The experimental yield of the first-generation organic nitrates from limonene-OH oxidation is calculated as (34 +/- 5) %, about 11 % higher than the value in the Master Chemical Mechanism (MCM), which is derived from structure-activity relationships (SARs). Time series of measured radicals, trace-gas concentrations, and OH reactivity are compared to results from zero-dimensional chemical box model calculations applying MCM v3.3.1. Modeled OH reactivity is 5 to 10 s(-1) (25 % to 33 % of the OH reactivity at the start of the experiment) higher than measured values at the end of the experiments under all chemical conditions investigated, suggesting either that there are unaccounted loss processes of limonene oxidation products or that products are less reactive toward OH. In addition, model calculations underestimate measured hydroperoxyl radical (HO2) concentrations by 20 % to 90 % and overestimate organic peroxyl radical (RO2) concentrations by 50 % to 300 %. The largest deviations are found in low-NO experiments and in the ozonolysis experiment. An OH radical budget analysis, which uses only measured quantities, shows that the budget is closed in most of the experiments. A similar budget analysis for RO2 radicals suggests that an additional RO2 loss rate constant of about (1-6) x 10(-2) s(-1) for first-generation RO2 is required to match the measured RO2 concentrations in all experiments. Sensitivity model runs indicate that additional reactions converting RO2 to HO2 at a rate constant of about (1.7-3.0) x 10(-2) s(-1) would improve the model-measurement agreement of NOx, HO2, and RO2 concentrations and OH reactivity. Reaction pathways that could lead to the production of additional OH and HO2 are discussed, which include isomerization reactions of RO2 from the oxidation of limonene, different branching ratios for the reaction of RO2 with HO2, and a faster rate constant for RO2 recombination reactions. As the exact chemical mechanisms of the additional HO2 and OH sources could not be identified, further work needs to focus on quantifying organic product species and organic peroxy radicals from limonene oxidation.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Pang, Jacky Yat Sing UNSPECIFIED UNSPECIFIED UNSPECIFIED Novelli, Anna UNSPECIFIED orcid.org/0000-0003-2077-7573 UNSPECIFIED Kaminski, Martin UNSPECIFIED UNSPECIFIED UNSPECIFIED Acir, Ismail-Hakki UNSPECIFIED UNSPECIFIED UNSPECIFIED Bohn, Birger UNSPECIFIED orcid.org/0000-0003-4177-3934 UNSPECIFIED Carlsson, Philip T. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Cho, Changmin UNSPECIFIED UNSPECIFIED UNSPECIFIED Dorn, Hans-Peter UNSPECIFIED UNSPECIFIED UNSPECIFIED Hofzumahaus, Andreas UNSPECIFIED UNSPECIFIED UNSPECIFIED Li, Xin UNSPECIFIED UNSPECIFIED UNSPECIFIED Lutz, Anna UNSPECIFIED UNSPECIFIED UNSPECIFIED Nehr, Sascha UNSPECIFIED orcid.org/0000-0002-1882-3625 UNSPECIFIED Reimer, David UNSPECIFIED UNSPECIFIED UNSPECIFIED Rohrer, Franz UNSPECIFIED UNSPECIFIED UNSPECIFIED Tillmann, Ralf UNSPECIFIED orcid.org/0000-0003-0648-6622 UNSPECIFIED Wegener, Robert UNSPECIFIED UNSPECIFIED UNSPECIFIED Kiendler-Scharr, Astrid UNSPECIFIED UNSPECIFIED UNSPECIFIED Wahner, Andreas UNSPECIFIED UNSPECIFIED UNSPECIFIED Fuchs, Hendrik UNSPECIFIED orcid.org/0000-0003-1263-0061 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-688211
DOI:	10.5194/acp-22-8497-2022
Journal or Publication Title:	Atmos. Chem. Phys.
Volume:	22
Number:	13
Page Range:	S. 8497 - 8528
Date:	2022
Publisher:	COPERNICUS GESELLSCHAFT MBH
Place of Publication:	GOTTINGEN
ISSN:	1680-7324
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language VOLATILE ORGANIC-COMPOUNDS; LASER-INDUCED FLUORESCENCE; GAS-PHASE REACTIONS; PEARL RIVER DELTA; PEROXY-RADICALS; ALPHA-PINENE; TROPOSPHERIC DEGRADATION; PHOTOLYSIS FREQUENCIES; OXIDATION-PRODUCTS; HO2 CONCENTRATIONS Multiple languages Environmental Sciences; Meteorology & Atmospheric Sciences Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/68821