edu.ucar.opensky::articles:23344 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-25T15:27:34.580547 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7v98bp4 Observational constraints on the formation of Cl2 from the reactive uptake of ClNO2 on aerosols in the polluted marine boundary layer 2019-08-13T00:00:00Z publication https://n2t.org/ark:/85065/d7v98bp4 https://doi.org/10.1029/2019JD030627 Haskins, J. D. author Lee, B. H. author Lopez-Hilifiker, F. D. author Peng, Q. author Jaeglé, L. author Reeves, John Michael author Schroder, J. C. author Campuzano-Jost, P. author Fibiger, D. author McDuffie, E. E. author Jiménez, J. L. author Brown, S. S. author Thornton, J. A. author UCAR/NCAR - Library publisher We use observations from the 2015 Wintertime Investigation of Transport, Emissions, and Reactivity (WINTER) aircraft campaign to constrain the proposed mechanism of Cl-2 production from ClNO2 reaction in acidic particles. To reproduce Cl-2 concentrations observed during WINTER with a chemical box model that includes ClNO2 reactive uptake to form Cl-2, the model required the ClNO2 reaction probability, gamma (ClNO2), to range from 6 x 10(-6) to 7 x 10(-5), with a mean value of 2.3 x 10(-5) (1.8 x 10(-5)). These field-determined gamma (ClNO2) are more than an order of magnitude lower than those determined in previous laboratory experiments on acidic surfaces, even when calculated particle pH is <= 2. We hypothesize this is because thick salt films in the laboratory enhanced the reactive uptake ClNO2 compared to that which would occur in submicron aerosol particles. Using the reacto-diffusive length-scale framework, we show that the field and laboratory observations can be reconciled if the net aqueous-phase reaction rate constant for ClNO2 (aq) + Cl-(aq) in acidic particles is on the order of 10(4) s(-1). We show that wet particle diameter and particulate chloride mass together explain 90% of the observed variance in the box model-derived gamma (ClNO2), implying that the availability of chloride and particle volume limit the efficiency of the reaction. Despite a much lower conversion of ClNO2 into Cl-2, this mechanism can still be responsible for the nocturnal formation of 10-20 pptv of Cl-2 in polluted regions, yielding an atmospherically relevant concentration of Cl atoms the following morning. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright 2019 American Geophysical Union. None eng geoscientificInformation