Oxidation flow reactors (OFRs) using low-pressure Hg lamp emission at 185 and 254 nm produce OH radicals efficiently and are widely used in atmospheric chemistry and other fields. However, knowledge of detailed OFR chemistry is limited, allowing speculation in the literature about whether some non-OH reactants, including several not relevant for tropospheric chemistry, may play an important role in these OFRs. These non-OH reactants are UV radiation, O(D-1), O(P-3), and O-3. In this study, we investigate the relative importance of other reactants to OH for the fate of reactant species in OFR under a wide range of conditions via box modeling. The relative importance of non-OH species is less sensitive to UV light intensity than to water vapor mixing ratio (H2O) and external OH reactivity (OHRext), as both non-OH reactants and OH scale roughly proportionally to UV intensity. We show that for field studies in forested regions and also the urban area of Los Angeles, reactants of atmospheric interest are predominantly consumed by OH. We find that O(D-1), O(P-3), and O-3 have relative contributions to volatile organic compound (VOC) consumption that are similar or lower than in the troposphere. The impact of O atoms can be neglected under most conditions in both OFR and troposphere. We define "riskier OFR conditions" as those with either low H2O (< 0.1%) or high OHRext (>= 100 s(-1) in OFR185 and > 200s(-1) in OFR254). We strongly suggest avoiding such conditions as the importance of non-OH reactants can be substantial for the most sensitive species, although OH may still dominate under some riskier conditions, depending on the species present. Photolysis at non-tropospheric wavelengths (185 and 254nm) may play a significant (> 20%) role in the degradation of some aromatics, as well as some oxidation intermediates, under riskier reactor conditions, if the quantum yields are high. Under riskier conditions, some biogenics can have substantial destructions by O-3, similarly to the troposphere. Working under low O-2 (volume mixing ratio of 0.002) with the OFR185 mode allows OH to completely dominate over O-3 reactions even for the biogenic species most reactive with O-3. Non-tropospheric VOC photolysis may have been a problem in some laboratory and source studies, but can be avoided or lessened in future studies by diluting source emissions and working at lower precursor concentrations in laboratory studies and by humidification. Photolysis of secondary organic aerosol (SOA) samples is estimated to be significant (> 20%) under the upper limit assumption of unity quantum yield at medium (1 x 10(13) and 1.5 x 10(15) photons cm(-2) s(-1) at 185 and 254 nm, respectively) or higher UV flux settings. The need for quantum yield measurements of both VOC and SOA photolysis is highlighted in this study. The results of this study allow improved OFR operation and experimental design and also inform the design of future reactors.
Wells, K. C.; Millet, D. B.; Bousserez, N.; Henze, D. K.; Griffis, T. J.; Chaliyakunnel, S.; Dlugokencky, E. J.; Saikawa, E.; Xiang, G.; Prinn, R. G.; O'Doherty, S.; Young, D.; Weiss, R. F.; Dutton, G. S.; Elkins, J. W.; Krummel, P. B.; Langenfelds, R.; Steele, L. P.;
Published Date:
2018
Source:
Atmospheric Chemistry and Physics, 18(2), 735-756.
Description:
We present top-down constraints on global monthly N2O emissions for 2011 from a multi-inversion approach and an ensemble of surface observations. The inversions employ the GEOS-Chem adjoint and an array of aggregation strategies to test how well curr...
Raczka, B.; Biraud, S. C.; Ehleringer, J. R.; Lai, C. T.; Miller, J. B.; Pataki, D. E.; Saleska, S. R.; Torn, M. S.; Vaughn, B. H.; Wehr, R.; Bowling, D. R.;
Published Date:
2017
Source:
Journal of Geophysical Research-Biogeosciences, 122(8), 1969-1987.
Description:
The seasonal pattern of the carbon isotope content (delta C-13) of atmospheric CO2 depends on local and nonlocal land-atmosphere exchange and atmospheric transport. Previous studies suggested that the delta C-13 of the net land-atmosphere CO2 flux (d...
Journal of Geophysical Research-Atmospheres, 123(15), 7950-7973.
Description:
In this study, we analyze a set of agroclimatological indices across West Africa and assess their projected changes for the future. We apply the regional climate model CCLM (COnsortium for Small-scale MOdelling in CLimate Mode) with a high spatial re...
Kenagy, H. S.; Sparks, T. L.; Ebben, C. J.; Wooldrige, P. J.; Lopez-Hilfiker, F. D.; Lee, B. H.; Thornton, J. A.; McDuffie, E. E.; Fibiger, D. L.; Brown, S. S.; Montzka, D. D.; Weinheimer, A. J.; Schroder, J. C.; Campuzano-Jost, P.; Day, D. A.; Jimenez, J. L.; Dibb, J. E.; Campos, T.; Shah, V.; Jaegle, L.; Cohen, R. C.;
Published Date:
2018
Source:
Journal of Geophysical Research-Atmospheres, 123(17), 9813-9827.
Description:
Although urban NOx lifetimes have been examined extensively during summertime conditions, wintertime NOx chemistry has been comparatively less studied. We use measurements of NOx and its oxidation products from the aircraft-based WINTER (Wintertime I...
Jarvinen, E.; Ignatius, K.; Nichman, L.; Kristensen, T. B.; Fuchs, C.; Hoyle, C. R.; Hoppel, N.; Corbin, J. C.; Craven, J.; Duplissy, J.; Ehrhart, S.; El Haddad, I.; Frege, C.; Gordon, H.; Jokinen, T.; Kallinger, P.; Kirkby, J.; Kiselev, A.; Naumann, K. H.; Petaja, T.; Pinterich, T.; Prevot, A. S. H.; Saathoff, H.; Schiebel, T.; Sengupta, K.; Simon, M.; Slowik, J. G.; Trostl, J.; Virtanen, A.; Vochezer, P.; Vogt, S.; Wagner, A. C.; Wagner, R.; Williamson, C.; Winkler, P. M.; Yan, C.; Baltensperger, U.; Donahue, N. M.; Flagan, R. C.; Gallagher, M.; Hansel, A.; Kulmala, M.; Stratmann, F.; Worsnop, D. R.; Mohler, O.; Leisner, T.; Schnaiter, M.;
Published Date:
2016
Source:
Atmospheric Chemistry and Physics, 16(7), 4423-4438.
Description:
Under certain conditions, secondary organic aerosol (SOA) particles can exist in the atmosphere in an amorphous solid or semi-solid state. To determine their relevance to processes such as ice nucleation or chemistry occurring within particles requir...
Butler, R.; Palmer, P. I.; Feng, L.; Andrews, S. J.; Atlas, E. L.; Carpenter, L. J.; Donets, V.; Harris, N. R. P.; Montzka, S. A.; Pan, L. L.; Salawitch, R. J.; Schauffler, S. M.;
Published Date:
2018
Source:
Atmospheric Chemistry and Physics, 18(17), 13135-13153.
Description:
We use the GEOS-Chem global 3-D atmospheric chemistry transport model to interpret atmospheric observations of bromoform (CHBr3) and dibromomethane (CH2Br2) collected during the CAST and CONTRAST aircraft measurement campaigns over the western Pacifi...
Fried, A.; Barth, M. C.; Bela, M.; Weibring, P.; Richter, D.; Walega, J.; Li, Y.; Pickering, K.; Apel, E.; Hornbrook, R.; Hills, A.; Riemer, D. D.; Blake, N.; Blake, D. R.; Schroeder, J. R.; Luo, Z. J.; Crawford, J. H.; Olson, J.; Rutledge, S.; Betten, D.; Biggerstaff, M. I.; Diskin, G. S.; Sachse, G.; Campos, T.; Flocke, F.; Weinheimer, A.; Cantrell, C.; Pollack, I.; Peischl, J.; Froyd, K.; Wisthaler, A.; Mikoviny, T.; Woods, S.;
Published Date:
2016
Source:
Journal of Geophysical Research-Atmospheres, 121(12), 7430-7460.
Description:
We have developed semi-independent methods for determining CH2O scavenging efficiencies (SEs) during strong midlatitude convection over the western, south-central Great Plains, and southeastern regions of the United States during the 2012 Deep Convec...
Janssens-Maenhout, G.; Crippa, M.; Guizzardi, D.; Dentener, F.; Muntean, M.; Pouliot, G.; Keating, T.; Zhang, Q.; Kurokawa, J.; Wankmuller, R.; van der Gon, H. D.; Kuenen, J. J. P.; Klimont, Z.; Frost, G.; Darras, S.; Koffi, B.; Li, M.;
Published Date:
2015
Source:
Atmospheric Chemistry and Physics, 15(19), 11411-11432.
Description:
The mandate of the Task Force Hemispheric Transport of Air Pollution (TF HTAP) under the Convention on Long-Range Transboundary Air Pollution (CLRTAP) is to improve the scientific understanding of the intercontinental air pollution transport, to quan...
Brown, S. S.; Dube, W. P.; Tham, Y. J.; Zha, Q. Z.; Xue, L. K.; Poon, S.; Wang, Z.; Blake, D. R.; Tsui, W.; Parrish, D. D.; Wang, T.;
Published Date:
2016
Source:
Journal of Geophysical Research-Atmospheres, 121(5), 2457-2475.
Description:
Nighttime reactions of nitrogen oxides influence ozone, volatile organic compounds, and aerosol and are thus important to the understanding of regional air quality. Despite large emissions and rapid recent growth of nitrogen oxide concentrations, the...
Kim, J.; Johnson, L. E.; Cifelli, R.; Choi, J.; Chandrasekar, V.;
Published Date:
2018
Source:
Water, 10(7), 21.
Description:
Soil moisture retention (SMR) capacity plays a key role in estimating the direct runoff when a multi-pulse storm event occurs. It is very important to know how much SMR will be recovered during the intervals of no rain of a multi-pulse storm. This st...
Fairall, C. W.; Matrosov, S. Y.; Williams, C. R.; Walsh, E. J.;
Published Date:
2018
Source:
Journal of Atmospheric and Oceanic Technology, 35(3), 593-608.
Description:
The NOAA W-band radar was deployed on a P-3 aircraft during a study of storm fronts off the U.S. West Coast in 2015 in the second CalWater (CalWater-2) field program. This paper presents an analysis of measured equivalent radar reflectivity factor Z(...
A 4-year record of aerosol size and hygroscopic growth factor distributions measured at the Department of Energy's Southern Great Plains (SGP) site in Oklahoma, U.S. were used to estimate supersaturation (S)-dependent cloud condensation nuclei concen...
Mahoney, K.; Swales, D.; Mueller, M. J.; Alexander, M.; Hughes, M.; Malloy, K.;
Published Date:
2018
Source:
Journal of Climate, 31(16), 6281-6297.
Description:
Atmospheric rivers (ARs) are well-known producers of precipitation along the U.S. West Coast. Depending on their intensity, orientation, and location of landfall, some ARs penetrate inland and cause heavy rainfall and flooding hundreds of miles from ...
Dimdore-Miles, O. B.; Palmer, P. I.; Bruhwiler, L. P.;
Published Date:
2018
Source:
Atmospheric Chemistry and Physics, 18(24), 17895-17907.
Description:
We consider the utility of the annual inter-polar difference (IPD) as a metric for changes in Arctic emissions of methane (CH4). The IPD has been previously defined as the difference between weighted annual means of CH4 mole fraction data collected a...
Sea surface temperature anomalies (SSTA) in portions of the extratropics are known to recur from one winter to the next without persisting through the intervening summer. Previous studies identified only a limited number of midlatitude regions where ...
Richardson, K.; Asmutis-Silvia, R.; Drinkwin, J.; Gilardi, K. V. K.; Giskes, I.; Jones, G.; O'Brien, K.; Pragnell-Raasch, H.; Ludwig, L.; Antonelis, K.; Barco, S.; Henry, A.; Knowlton, A.; Landry, S.; Mattila, D.; MacDonald, K.; Moore, M.; Morgan, J.; Robbins, J.; van der Hoop, J.; Hogan, E.;
Published Date:
2019
Source:
Marine Pollution Bulletin, 138, 222-229.
Description:
Abandoned, lost or discarded fishing gear (ALDFG) comprises a significant amount of global marine debris, with diverse impacts to marine environments, wildlife, and the fishing industry. Building evidence on ALDFG is critical to holistically understa...
Smith, M.; Stammerjohn, S.; Persson, O.; Rainville, L.; Liu, G. Q.; Perrie, W.; Robertson, R.; Jackson, J.; Thomson, J.;
Published Date:
2018
Source:
Journal of Geophysical Research-Oceans, 123(5), 3164-3185.
Description:
High-resolution measurements of the air-ice-ocean system during an October 2015 event in the Beaufort Sea demonstrate how stored ocean heat can be released to temporarily reverse seasonal ice advance. Strong on-ice winds over a vast fetch caused mixi...
Chakraborty, A.; Ervens, B.; Gupta, T.; Tripathi, S. N.;
Published Date:
2016
Source:
Journal of Geophysical Research-Atmospheres, 121(8), 4317-4332.
Description:
Size-resolved fog water samples were collected in two consecutive winters at Kanpur, a heavily polluted urban area of India. Samples were analyzed by an aerosol mass spectrometer after drying and directly in other instruments. Residues of fine fog dr...
Kim, P. S.; Jacob, D. J.; Fisher, J. A.; Travis, K.; Yu, K.; Zhu, L.; Yantosca, R. M.; Sulprizio, M. P.; Jimenez, J. L.; Campuzano-Jost, P.; Froyd, K. D.; Liao, J.; Hair, J. W.; Fenn, M. A.; Butler, C. F.; Wagner, N. L.; Gordon, T. D.; Welti, A.; Wennberg, P. O.; Crounse, J. D.; St. Clair, J. M.; Teng, A. P.; Millet, D. B.; Schwarz, J. P.; Markovic, M. Z.; Perring, A. E.;
Heiblum, R. H.; Altaratz, O.; Koren, I.; Feingold, G.; Kostinski, A. B.; Khain, A. P.; Ovchinnikov, M.; Fredj, E.; Dagan, G.; Pinto, L.; Yaish, R.; Chen, Q.;
Published Date:
2016
Source:
Journal of Geophysical Research-Atmospheres, 121(11), 6336-6355.
Description:
We study the evolution of warm convective cloud fields using large eddy simulations of continental and trade cumulus. Individual clouds are tracked a posteriori from formation to dissipation using a 3-D cloud-tracking algorithm, and results are prese...
Oxidation flow reactors (OFRs) using OH produced from low-pressure Hg lamps at 254 nm (OFR254) or both 185 and 254 nm (OFR185) are commonly used in atmospheric chemistry and other fields. OFR254 requires the addition of externally formed O-3 since OH...
Peng, Zhe; Lee-Taylor, Julia; Orlando, John L.; Tyndall, Geoffrey S.; Jimenex, Jose L.;
Published Date:
2019
Source:
Atmos. Chem. Phys., 19, 813–834, 2019
Description:
Oxidation flow reactors (OFRs) are a promising complement to environmental chambers for investigating atmospheric oxidation processes and secondary aerosol formation. However, questions have been raised about how representative the chemistry within O...