Measurements of CH3O2NO2 in the upper troposphere

作者：Nault B A; Garland C; Pusede S E; Wooldridge P J; Ullmann K; Hall S R; Cohen R C^*

来源：Atmospheric Measurement Techniques, 2015, 8(2): 987-997.

DOI：10.5194/amt-8-987-2015

Methyl peroxy nitrate (CH3O2NO2) is a nonacyl peroxy nitrate that is important for photochemistry at low temperatures characteristic of the upper troposphere. We report the first measurements of CH3O2NO2, which we achieved through a new aircraft inlet configuration, combined with thermal-dissociation laser-induced fluorescence (TD-LIF) detection of NO2, and describe the accuracy, specificity, and interferences to CH3O2NO2 measurements. CH3O2NO2 is predicted to be a ubiquitous interference to upper-tropospheric NO2 measurements. We describe an experimental strategy for obtaining NO2 observations free of the CH3O2NO2 interference. Using these new methods, we made observations during two recent aircraft campaigns: the Deep Convective Clouds and Chemistry (DC-3) and the Studies of Emissions and Atmospheric Composition, Clouds, and Climate Coupling by Regional Surveys (SEAC4RS) experiments. The CH3O2NO2 measurements we report have a detection limit (S / N = 2) of 15 pptv at 1 min averaging on a background of 200 pptv NO2 and an accuracy of +/- 40 %. Observations are used to constrain the interference of pernitric acid (HO2NO2) to the CH3O2NO2 measurements, as HO2NO2 partially decomposes (similar to 11 %) along with CH3O2NO2 in the heated CH3O2NO2 channel used to detect CH3O2NO2.

• 出版日期2015