pH is a fundamental aerosol property that affects ambient particle concentration and composition, linking pH to all aerosol environmental impacts. Here, PM1 and PM2.5 pH are calculated based on data from measurements during the California Research at the Nexus of Air Quality and Climate Change (CalNex) study from 15 May to 15 June 2010 in Pasadena, CA. Particle pH and water were predicted with the ISORROPIA-II thermodynamic model and validated by comparing predicted to measured gas-particle partitioning of inorganic nitrate, ammonium, and chloride. The study mean +/- standard deviation PM1 pH was 1.9 +/- 0.5 for the SO42-NO3-NH4+-HNO3-NH3 system. For PM2.5, internal mixing of sea salt components (SO42-NO3--NH4+-Na+-Cl--K+-HNO3-NH3-HCl system) raised the bulk pH to 2.7 +/- 0.3 and improved predicted nitric acid partitioning with PM2.5 components. The results show little effect of sea salt on PM1 pH, but significant effects on PM2.5 pH. A mean PM1 pH of 1.9 at Pasadena was approximately one unit higher than what we have reported in the southeastern US, despite similar temperature, relative humidity, and sulfate ranges, and is due to higher total nitrate concentrations (nitric acid plus nitrate) relative to sulfate, a situation where particle water is affected by semi-volatile nitrate concentra-tions. Under these conditions nitric acid partitioning can further promote nitrate formation by increasing aerosol water, which raises pH by dilution, further increasing nitric acid partitioning and resulting in a significant increase in fine particle nitrate and pH. This study provides insights into the complex interactions between particle pH and nitrate in a summertime coastal environment and a contrast to recently reported pH in the eastern US in summer and winter and the eastern Mediterranean. All studies have consistently found highly acidic PM1 with pH generally below 3.
Lerner, B. M.; Gilman, J. B.; Aikin, K. C.; Atlas, E. L.; Goldan, P. D.; Graus, M.; Hendershot, R.; Isaacman-VanWertz, G. A.; Koss, A.; Kuster, W. C.; Lueb, R. A.; McLaughlin, R. J.; Peischl, J.; Sueper, D.; Ryerson, T. B.; Tokarek, T. W.; Warneke, C.; Yuan, B.; de Gouw, J. A.;
Volatile organic compounds were quantified during two aircraft-based field campaigns using highly automated, whole air samplers with expedited post-flight analysis via a new custom-built, field-deployable gas chromatography-mass spectrometry instrume...
Tevlin, A. G.; Li, Y.; Collett, J. L.; McDuffie, E. E.; Fischer, E. V.; Murphy, J. G.;
Published Date:
2017
Source:
Journal of Geophysical Research-Atmospheres, 122(22), 12468-12487.
Description:
Ammonia (NH3) mixing ratios were measured between the surface and 280m aboveground level from a moveable carriage at the Boulder Atmospheric Observatory tower in summer 2014 as part of the Front Range Air Pollution and Photochemistry Experiment. The ...
Colette, A.; Andersson, C.; Manders, A.; Mar, K.; Mircea, M.; Pay, M. T.; Raffort, V.; Tsyro, S.; Cuvelier, C.; Adani, M.; Bessagnet, B.; Bergstrom, R.; Briganti, G.; Butler, T.; Cappelletti, A.; Couvidat, F.; D'Isidoro, M.; Doumbia, T.; Fagerli, H.; Granier, C.; Heyes, C.; Klimont, Z.; Ojha, N.; Otero, N.; Schaap, M.; Sindelarova, K.; Stegehuis, A. I.; Roustan, Y.; Vautard, R.; van Meijgaard, E.; Vivanco, M. G.; Wind, P.;
Published Date:
2017
Source:
Geoscientific Model Development, 10(9), 3255-3276.
Description:
The EURODELTA-Trends multi-model chemistry-transport experiment has been designed to facilitate a better understanding of the evolution of air pollution and its drivers for the period 1990-2010 in Europe. The main objective of the experiment is to as...
We describe the University of Colorado mobile Solar Occultation Flux instrument (CU mobile SOF). The instrument consists of a digital mobile solar tracker that is coupled to a Fourier transform spectrometer (FTS) of 0.5 cm (-1) resolution and a UV-vi...
Giordano, M. R.; Kalnajs, L. E.; Avery, A.; Goetz, J. D.; Davis, S. M.; DeCarlo, P. F.;
Published Date:
2017
Source:
Atmospheric Chemistry and Physics, 17(1), 1-20.
Description:
Understanding the sources and evolution of aerosols is crucial for constraining the impacts that aerosols have on a global scale. An unanswered question in atmospheric science is the source and evolution of the Antarctic aerosol population. Previous ...
Sayers, M. J.; Grimm, A. G.; Shuchman, R. A.; Bosse, K. R.; Fahnenstiel, G. L.; Ruberg, S. A.; Leshkevich, G. A.;
Published Date:
2019
Source:
Journal of Great Lakes Research, 45(3), 508-521.
Description:
Blooms of harmful cyanobacteria (cyanoHABs) have occurred on an annual basis in western Lake Erie for more than a decade. Previously, we developed and validated an algorithm to map the extent of the submerged and surface scum components of cyanoHABs ...
Hill, M. C.; Bendlin, A. R.; Van Cise, A. M.; Milette-Winfree, A.; Ligon, A. D.; Ü, A. C.; Deakos, M. H.; Oleson, E. M.;
Published Date:
2019
Source:
Marine Mammal Science, 35(3), 797-824.
Description:
Abstract Little is known about short-finned pilot whales (Globicephala macrorhynchus) in the western North Pacific outside of Japanese coastal waters. To expand understanding of short-finned pilot whale ecology in the region, we conducted small-boat ...
Journal of Advances in Modeling Earth Systems, 9(1), 627-646.
Description:
Low and high clouds of shallow extent, especially stratocumulus and even more so for high-level cirrus clouds that reside where vertical resolution is particularly coarse, are poorly represented in large-scale models such as global climate models and...
Butler, A. H.; Sjoberg, J. P.; Seidel, D. J.; Rosenlof, K. H.;
Published Date:
2017
Source:
Earth System Science Data, 9(1), 63-76.
Description:
Major, sudden midwinter stratospheric warmings (SSWs) are large and rapid temperature increases in the winter polar stratosphere are associated with a complete reversal of the climatological westerly winds (i.e., the polar vortex). These extreme even...
Jensen, E. J.; Karcher, B.; Ueyama, R.; Pfister, L.; Bui, T. V.; Diskin, G. S.; DiGangi, J. P.; Woods, S.; Lawson, R. P.; Froyd, K. D.; Murphy, D. M.;
Published Date:
2018
Source:
Journal of Geophysical Research-Atmospheres, 123(21), 12210-12227.
Description:
Recent laboratory experiments have advanced our understanding of heterogeneous ice nucleation at low temperatures. We use these laboratory results, along with field measurements of aerosol composition, to constrain a parameterization of heterogeneous...
Stauffer, R. M.; Thompson, A. M.; Oltmans, S. J.; Johnson, B. J.;
Published Date:
2017
Source:
Journal of Geophysical Research-Atmospheres, 122(2), 1261-1280.
Description:
Much attention has been focused on the transport of ozone (O-3) to the western U.S., particularly given the latest revision of the National Ambient Air Quality Standard to 70 parts per billion by volume (ppbv) of O-3. This makes quantifying the contr...
Jathar, S. H.; Heppding, C.; Link, M. F.; Farmer, D. K.; Akherati, A.; Kleeman, M. J.; de Gouw, J. A.; Veres, P. R.; Roberts, J. M.;
Published Date:
2017
Source:
Atmospheric Chemistry and Physics, 17(14), 8959-8970.
Description:
Isocyanic acid (HNCO), an acidic gas found in tobacco smoke, urban environments, and biomass-burning-affected regions, has been linked to adverse health outcomes. Gasoline-and diesel-powered engines and biomass burning are known to emit HNCO and hypo...
Barkley, H. C.; Cohen, A. L.; Mollica, N. R.; Brainard, R. E.; Rivera, H. E.; DeCarlo, T. M.; Lohmann, G. P.; Drenkard, E. J.; Alpert, A. E.; Young, C. W.; Vargas-Ángel, B.; Lino, K. C.; Oliver, T. A.; Pietro, K. R.; Luu, V. H.;
Published Date:
2018
Source:
Communications Biology, 1(1), 177.
Description:
The oceans are warming and coral reefs are bleaching with increased frequency and severity, fueling concerns for their survival through this century. Yet in the central equatorial Pacific, some of the world’s most productive reefs regularly experie...
Yuan, B.; Coggon, M. M.; Koss, A. R.; Warneke, C.; Eilerman, S.; Peischl, J.; Aikin, K. C.; Ryerson, T. B.; de Gouw, J. A.;
Published Date:
2017
Source:
Atmospheric Chemistry and Physics, 17(8), 4945-4956.
Description:
Concentrated animal feeding operations (CAFOs) emit a large number of volatile organic compounds (VOCs) to the atmosphere. In this study, we conducted mobile laboratory measurements of VOCs, methane (CH4) and ammonia (NH3) downwind of dairy cattle, b...
Observations of atmospheric trace gases in the tropical upper troposphere (UT), tropical tropopause layer (TTL), and lower stratosphere (LS) require dedicated measurement platforms and instrumentation. Here we present a new limb-scanning Differential...
Palm, B. B.; Campuzano-Jost, P.; Day, D. A.; Ortega, A. M.; Fry, J. L.; Brown, S. S.; Zarzana, K. J.; Dube, W.; Wagner, N. L.; Draper, D. C.; Kaser, L.; Jud, W.; Karl, T.; Hansel, A.; Gutierrez-Montes, C.; Jimenez, J. L.;
Published Date:
2017
Source:
Atmospheric Chemistry and Physics, 17(8), 5331-5354.
Description:
Ambient pine forest air was oxidized by OH, O-3, or NO3 radicals using an oxidation flow reactor (OFR) during the BEACHON-RoMBAS (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics and Nitrogen - Rocky Mountain Biogenic Aero...
Long, C. S.; Fujiwara, M.; Davis, S.; Mitchell, D. M.; Wright, C. J.;
Published Date:
2017
Source:
Atmospheric Chemistry and Physics, 17(23), 14593-14629.
Description:
Two of the most basic parameters generated from a reanalysis are temperature and winds. Temperatures in the reanalyses are derived from conventional (surface and balloon), aircraft, and satellite observations. Winds are observed by conventional syste...
Perring, A. E.; Schwarz, J. P.; Markovic, M. Z.; Fahey, D. W.; Jimenez, J. L.; Campuzano-Jost, P.; Palm, B. D.; Wisthaler, A.; Mikoviny, T.; Diskin, G.; Sachse, G.; Ziemba, L.; Anderson, B.; Shingler, T.; Crosbie, E.; Sorooshian, A.; Yokelson, R.; Gao, R. S.;
Published Date:
2017
Source:
Journal of Geophysical Research-Atmospheres, 122(2), 1086-1097.
Description:
Water uptake by black carbon (BC)-containing aerosol was quantified in North American wildfire plumes of varying age (1 to similar to 40 h old) sampled during the SEAC(4)RS mission (2013). A Humidified Dual SP2 (HD-SP2) is used to optically size BC-c...
Miller, C. C.; Jacob, D. J.; Marais, E. A.; Yu, K. R.; Travis, K. R.; Kim, P. S.; Fisher, J. A.; Zhu, L.; Wolfe, G. M.; Hanisco, T. F.; Keutsch, F. N.; Kaiser, J.; Min, K. E.; Brown, S. S.; Washenfelder, R. A.; Abad, G. G.; Chance, K.;
Published Date:
2017
Source:
Atmospheric Chemistry and Physics, 17(14), 8725-8738.
Description:
Glyoxal (CHOCHO) is produced in the atmosphere by the oxidation of volatile organic compounds (VOCs). Like formaldehyde (HCHO), another VOC oxidation product, it is measurable from space by solar backscatter. Isoprene emitted by vegetation is the dom...
Bruhwiler, L. M.; Basu, S.; Bergamaschi, P.; Bousquet, P.; Dlugokencky, E.; Houweling, S.; Ishizawa, M.; Kim, H. S.; Locatelli, R.; Maksyutov, S.; Montzka, S.; Pandey, S.; Patra, P. K.; Petron, G.; Saunois, M.; Sweeney, C.; Schwietzke, S.; Tans, P.; Weatherhead, E. C.;
Published Date:
2017
Source:
Journal of Geophysical Research-Atmospheres, 122(7), 4070-4083.
Description:
Recent studies have proposed significant increases in CH4 emissions possibly from oil and gas (O&G) production, especially for the U.S. where O&G production has reached historically high levels over the past decade. In this study, we show that an ens...
Haskins, J. D.; Jaegle, L.; Shah, V.; Lee, B. H.; Lopez-Hilfiker, F. D.; Campuzano-Jost, P.; Schroder, J. C.; Day, D. A.; Guo, H. Y.; Sullivan, A. P.; Weber, R.; Dibb, J.; Campos, T.; Jimenez, J. L.; Brown, S. S.; Thornton, J. A.;
Published Date:
2018
Source:
Journal of Geophysical Research-Atmospheres, 123(22), 12897-12916.
Description:
The formation of photolabile chlorine reservoirs depend on how much chloride is available in the particle to react, which requires the chlorine partitioning to the particle in the troposphere to be well understood. However, limited measurements of ga...