Comparison of two photolytic calibration methods for nitrous acid

Abstract 2 O photolysis. In this work, we describe and compare two photolytic HONO calibration methods that were used to calibrate an iodide adduct chemical ionization mass spectrometer (CIMS). Both methods are based on the water vapor photolysis method commonly used for OH and HO2 (known collectively as HOx) calibrations. The first method is an adaptation of the common chemical actinometry HOx calibration method, in which HONO is calculated based on quantified values for [O3 ], [H2 O], and [O2 ] and the absorption cross sections for H2 O and O2 at 184.9 nm. In the second, novel method HONO is prepared in mostly N2 ([O2 ] = 0.040  %) and is simply quantified by measuring the NO2 formed by the reaction of NO with HO2 generated by H2 O photolysis. Both calibration methods were used to prepare a wide range of HONO mixing ratios between ∼ 400 and 8000 pptv. The uncertainty of the chemical actinometric calibration is 27 % (2 σ) and independent of HONO concentration. The uncertainty of the NO2 proxy calibration is concentration-dependent, limited by the uncertainty of the NO2 measurements. The NO2 proxy calibration uncertainties (2 σ) presented here range from 4.5 % to 24.4 % (at [HONO] = 8000  pptv and [HONO] = 630  pptv, respectively) with a 10 % uncertainty associated with a mixing ratio of ∼ 1600  pptv, typical of values observed in urban areas at night. We also describe the potential application of the NO2 proxy method to calibrating HOx instruments (e.g., LIF, CIMS) at uncertainties below 15 % (2 σ).

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch

References and Relationships

• Bibliographic citation: Comparison of two photolytic calibration methods for nitrous acid ; volume:15 ; number:18 ; year:2022 ; pages:5455-5464 ; extent:10 ; Atmospheric measurement techniques ; 15, Heft 18 (2022), 5455-5464 (gesamt 10)

Contributors, Places and Time

• Creator: Lindsay, Andrew J. ; Wood, Ezra C.

Further information

• DOI: 10.5194/amt-15-5455-2022
• URN: urn:nbn:de:101:1-2022092905212056062916
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 15.08.2025, 7:24 AM CEST