edu.ucar.opensky::articles:25107 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-24T22:53:17.035891 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d78s4tg8 https://doi.org/10.5065/D61V5CDP https Related Dataset #1 Manitou Experimental Forest Observatory Field Campaign https://doi.org/10.5067/Suborbital/KORUSAQ/DATA01 https Related Dataset #2 Korea United States Air Quality Study A systematic re-evaluation of methods for quantification of bulk particle-phase organic nitrates using real-time aerosol mass spectrometry 2022-01-27T00:00:00Z publication https://n2t.org/ark:/85065/d78s4tg8 https://doi.org/10.5194/amt-15-459-2022 Day, D. A. author Campuzano-Jost, P. author Nault, B. A. author Palm, Brett B. author Hu, W. author Guo, H. author Wooldridge, P. J. author Cohen, R. C. author Docherty, K. S. author Huffman, J. A. author de Sá, S. S. author Martin, S. T. author Jimenez, J. L. author UCAR/NCAR - Library publisher Organic nitrate (RONO2) formation in the atmosphere represents a sink of NOx (NOx = NO + NO2) and termination of the NOx/HOx (HOx = HO2 + OH) ozone formation and radical propagation cycles, can act as a NOx reservoir transporting reactive nitrogen, and contributes to secondary organic aerosol formation. While some fraction of RONO2 is thought to reside in the particle phase, particlephase organic nitrates (pRONO(2)) are infrequently measured and thus poorly understood. There is an increasing prevalence of aerosol mass spectrometer (AMS) instruments, which have shown promise for determining the quantitative total organic nitrate functional group contribution to aerosols. A simple approach that relies on the relative intensities of NO+ and NO2+ ions in the AMS spectrum, the calibrated NOx+ ratio for NH4NO3, and the inferred ratio for pRONO(2) has been proposed as a way to apportion the total nitrate signal to NH4NO3 and pRONO(2). This method is increasingly being applied to field and laboratory data. However, the methods applied have been largely inconsistent and poorly characterized, and, therefore, a detailed evaluation is timely. Here, we compile an extensive survey of NOx+ ratios measured for various pRONO(2) compounds and mixtures from multiple AMS instruments, groups, and laboratory and field measurements. All data and analysis presented here are for use with the standard AMS vaporizer. We show that, in the absence of pRONO(2) standards, the pRONO(2) NOx+ ratio can be estimated using a ratio referenced to the calibrated NH4NO3 ratio, a so-called "Ratioof-Ratios" method (RoR = 2.75 +/- 0.41). We systematically explore the basis for quantifying pRONO(2) (and NH4NO3) with the RoR method using ground and aircraft field measurements conducted over a large range of conditions. The method is compared to another AMS method (positive matrix factorization, PMF) and other pRONO(2) and related (e.g., total gas + particle RONO2) measurements, generally showing good agreement/correlation. A broad survey of ground and aircraft AMS measurements shows a pervasive trend of higher fractional contribution of pRONO(2) to total nitrate with lower total nitrate concentrations, which generally corresponds to shifts from urban-influenced to rural/remote regions. Compared to ground campaigns, observations from all aircraft campaigns showed substantially lower pRONO(2) contributions at midranges of total nitrate (0.01-0.1 up to 2-5 mu g m(-3)), suggesting that the balance of effects controlling NH4NO3 and pRONO(2) formation and lifetimes - such as higher humidity, lower temperatures, greater dilution, different sources, higher particle acidity, and pRONO(2) hydrolysis (possibly accelerated by particle acidity) - favors lower pRONO(2) contributions for those environments and altitudes sampled. 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 author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. None eng geoscientificInformation