000891564 001__ 891564 000891564 005__ 20240712101006.0 000891564 0247_ $$2doi$$a10.5194/amt-14-1851-2021 000891564 0247_ $$2ISSN$$a1867-1381 000891564 0247_ $$2ISSN$$a1867-8548 000891564 0247_ $$2Handle$$a2128/27626 000891564 0247_ $$2altmetric$$aaltmetric:101375049 000891564 0247_ $$2WOS$$aWOS:000626739200002 000891564 037__ $$aFZJ-2021-01589 000891564 082__ $$a550 000891564 1001_ $$0P:(DE-Juel1)174162$$aCho, Changmin$$b0 000891564 245__ $$aCharacterization of a chemical modulation reactor (CMR) for the measurement of atmospheric concentrations of hydroxyl radicals with a laser-induced fluorescence instrument 000891564 260__ $$aKatlenburg-Lindau$$bCopernicus$$c2021 000891564 3367_ $$2DRIVER$$aarticle 000891564 3367_ $$2DataCite$$aOutput Types/Journal article 000891564 3367_ $$0PUB:(DE-HGF)16$$2PUB:(DE-HGF)$$aJournal Article$$bjournal$$mjournal$$s1618557358_25192 000891564 3367_ $$2BibTeX$$aARTICLE 000891564 3367_ $$2ORCID$$aJOURNAL_ARTICLE 000891564 3367_ $$00$$2EndNote$$aJournal Article 000891564 520__ $$aPrecise and accurate hydroxyl radical (OH) measurements are essential to investigate mechanisms for oxidation and transformation of trace gases and processes leading to the formation of secondary pollutants like ozone (O3) in the troposphere. Laser-induced fluorescence (LIF) is a widely used technique for the measurement of ambient OH radicals and was used for the majority of field campaigns and chamber experiments. Recently, most LIF instruments in use for atmospheric measurements of OH radicals introduced chemical modulation to separate the ambient OH radical concentration from possible interferences by chemically removing ambient OH radicals before they enter the detection cell (Mao et al., 2012; Novelli et al., 2014a). In this study, we describe the application and characterization of a chemical modulation reactor (CMR) applied to the Forschungszentrum Jülich LIF (FZJ-LIF) instrument in use at the atmospheric simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber). Besides dedicated experiments in synthetic air, the new technique was extensively tested during the year-round Jülich Atmospheric Chemistry Project (JULIAC) campaign, in which ambient air was continuously flowed into the SAPHIR chamber. It allowed for performing OH measurement comparisons with differential optical absorption spectroscopy (DOAS) and investigation of interferences in a large variety of chemical and meteorological conditions. Good agreement was obtained in the LIF–DOAS intercomparison within instrumental accuracies (18 % for LIF and 6.5 % for DOAS) which confirms that the new chemical modulation system of the FZJ-LIF instrument is suitable for measurement of interference-free OH concentrations under the conditions of the JULIAC campaign (rural environment). Known interferences from O3+H2O and the nitrate radical (NO3) were quantified with the CMR in synthetic air in the chamber and found to be 3.0×105 and 0.6×105 cm−3, respectively, for typical ambient-air conditions (O3=50 ppbv, H2O = 1 % and NO3=10 pptv). The interferences measured in ambient air during the JULIAC campaign in the summer season showed a median diurnal variation with a median maximum value of 0.9×106 cm−3 during daytime and a median minimum value of 0.4×106 cm−3 at night. The highest interference of 2×106 cm−3 occurred in a heat wave from 22 to 29 August, when the air temperature and ozone increased to 40 ∘C and 100 ppbv, respectively. All observed interferences could be fully explained by the known O3+H2O interference, which is routinely corrected in FZJ-LIF measurements when no chemical modulation is applied. No evidence for an unexplained interference was found during the JULIAC campaign.A chemical model of the CMR was developed and applied to estimate the possible perturbation of the OH transmission and scavenging efficiency by reactive atmospheric trace gases. These can remove OH by gas phase reactions in the CMR or produce OH by non-photolytic reactions, most importantly by the reaction of ambient HO2 with NO. The interfering processes become relevant at high atmospheric OH reactivities. For the conditions of the JULIAC campaign with OH reactivities below 20 s−1, the influence on the determination of ambient OH concentrations was small (on average: 2 %). However, in environments with high OH reactivities, such as in a rain forest or megacity, the expected perturbation in the currently used chemical modulation reactor could be large (more than a factor of 2). Such perturbations need to be carefully investigated and corrected for the proper evaluation of OH concentrations when applying chemical scavenging. This implies that chemical modulation, which was developed to eliminate interferences in ambient OH measurements, itself can be subject to interferences that depend on ambient atmospheric conditions. 000891564 536__ $$0G:(DE-HGF)POF4-211$$a211 - Die Atmosphäre im globalen Wandel (POF4-211)$$cPOF4-211$$fPOF IV$$x0 000891564 588__ $$aDataset connected to CrossRef 000891564 7001_ $$0P:(DE-Juel1)16326$$aHofzumahaus, Andreas$$b1$$eCorresponding author 000891564 7001_ $$0P:(DE-Juel1)7363$$aFuchs, Hendrik$$b2 000891564 7001_ $$0P:(DE-Juel1)16317$$aDorn, Hans-Peter$$b3 000891564 7001_ $$0P:(DE-Juel1)173895$$aGlowania, Marvin$$b4 000891564 7001_ $$0P:(DE-Juel1)16342$$aHolland, Frank$$b5$$ufzj 000891564 7001_ $$0P:(DE-Juel1)16347$$aRohrer, Franz$$b6$$ufzj 000891564 7001_ $$0P:(DE-Juel1)171649$$aVardhan, Vaishali$$b7 000891564 7001_ $$0P:(DE-Juel1)4528$$aKiendler-Scharr, Astrid$$b8 000891564 7001_ $$0P:(DE-Juel1)16324$$aWahner, Andreas$$b9 000891564 7001_ $$0P:(DE-Juel1)166537$$aNovelli, Anna$$b10$$eCorresponding author 000891564 773__ $$0PERI:(DE-600)2505596-3$$a10.5194/amt-14-1851-2021$$gVol. 14, no. 3, p. 1851 - 1877$$n3$$p1851 - 1877$$tAtmospheric measurement techniques$$v14$$x1867-8548$$y2021 000891564 8564_ $$uhttps://juser.fz-juelich.de/record/891564/files/invoice_Helmholtz-PUC-2021-21.pdf 000891564 8564_ $$uhttps://juser.fz-juelich.de/record/891564/files/amt-14-1851-2021.pdf$$yOpenAccess 000891564 8767_ $$8Helmholtz-PUC-2021-21$$92021-04-01$$d2021-04-12$$eAPC$$jZahlung erfolgt$$pamt-2020-359$$zBelegnr. 1200165527 / 2021 000891564 909CO $$ooai:juser.fz-juelich.de:891564$$pdnbdelivery$$popenCost$$pVDB$$pVDB:Earth_Environment$$pdriver$$pOpenAPC$$popen_access$$popenaire 000891564 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)174162$$aForschungszentrum Jülich$$b0$$kFZJ 000891564 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)16326$$aForschungszentrum Jülich$$b1$$kFZJ 000891564 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)7363$$aForschungszentrum Jülich$$b2$$kFZJ 000891564 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)16317$$aForschungszentrum Jülich$$b3$$kFZJ 000891564 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)16342$$aForschungszentrum Jülich$$b5$$kFZJ 000891564 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)16347$$aForschungszentrum Jülich$$b6$$kFZJ 000891564 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)4528$$aForschungszentrum Jülich$$b8$$kFZJ 000891564 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)16324$$aForschungszentrum Jülich$$b9$$kFZJ 000891564 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)166537$$aForschungszentrum Jülich$$b10$$kFZJ 000891564 9130_ $$0G:(DE-HGF)POF3-243$$1G:(DE-HGF)POF3-240$$2G:(DE-HGF)POF3-200$$3G:(DE-HGF)POF3$$4G:(DE-HGF)POF$$aDE-HGF$$bErde und Umwelt$$lAtmosphäre und Klima$$vTropospheric trace substances and their transformation processes$$x0 000891564 9131_ $$0G:(DE-HGF)POF4-211$$1G:(DE-HGF)POF4-210$$2G:(DE-HGF)POF4-200$$3G:(DE-HGF)POF4$$4G:(DE-HGF)POF$$aDE-HGF$$bForschungsbereich Erde und Umwelt$$lErde im Wandel – Unsere Zukunft nachhaltig gestalten$$vDie Atmosphäre im globalen Wandel$$x0 000891564 9141_ $$y2021 000891564 915__ $$0StatID:(DE-HGF)0200$$2StatID$$aDBCoverage$$bSCOPUS$$d2021-01-31 000891564 915__ $$0StatID:(DE-HGF)0160$$2StatID$$aDBCoverage$$bEssential Science Indicators$$d2021-01-31 000891564 915__ $$0LIC:(DE-HGF)CCBY4$$2HGFVOC$$aCreative Commons Attribution CC BY 4.0 000891564 915__ $$0StatID:(DE-HGF)0600$$2StatID$$aDBCoverage$$bEbsco Academic Search$$d2021-01-31 000891564 915__ $$0StatID:(DE-HGF)0100$$2StatID$$aJCR$$bATMOS MEAS TECH : 2019$$d2021-01-31 000891564 915__ $$0StatID:(DE-HGF)0501$$2StatID$$aDBCoverage$$bDOAJ Seal$$d2021-01-31 000891564 915__ $$0StatID:(DE-HGF)0500$$2StatID$$aDBCoverage$$bDOAJ$$d2021-01-31 000891564 915__ $$0StatID:(DE-HGF)0113$$2StatID$$aWoS$$bScience Citation Index Expanded$$d2021-01-31 000891564 915__ $$0StatID:(DE-HGF)0700$$2StatID$$aFees$$d2021-01-31 000891564 915__ $$0StatID:(DE-HGF)0150$$2StatID$$aDBCoverage$$bWeb of Science Core Collection$$d2021-01-31 000891564 915__ $$0StatID:(DE-HGF)9900$$2StatID$$aIF < 5$$d2021-01-31 000891564 915__ $$0StatID:(DE-HGF)0510$$2StatID$$aOpenAccess 000891564 915__ $$0StatID:(DE-HGF)0030$$2StatID$$aPeer Review$$bASC$$d2021-01-31 000891564 915__ $$0StatID:(DE-HGF)0561$$2StatID$$aArticle Processing Charges$$d2021-01-31 000891564 915__ $$0StatID:(DE-HGF)1150$$2StatID$$aDBCoverage$$bCurrent Contents - Physical, Chemical and Earth Sciences$$d2021-01-31 000891564 915__ $$0StatID:(DE-HGF)0300$$2StatID$$aDBCoverage$$bMedline$$d2021-01-31 000891564 915__ $$0StatID:(DE-HGF)0199$$2StatID$$aDBCoverage$$bClarivate Analytics Master Journal List$$d2021-01-31 000891564 9201_ $$0I:(DE-Juel1)IEK-8-20101013$$kIEK-8$$lTroposphäre$$x0 000891564 9801_ $$aAPC 000891564 9801_ $$aFullTexts 000891564 980__ $$ajournal 000891564 980__ $$aVDB 000891564 980__ $$aUNRESTRICTED 000891564 980__ $$aI:(DE-Juel1)IEK-8-20101013 000891564 980__ $$aAPC 000891564 981__ $$aI:(DE-Juel1)ICE-3-20101013