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1. A regional scale modeling analysis of aerosol and trace gas distributions over the eastern Pacific during the INTEX-B field campaign

Author

Adhikary, B., Carmichael, G. R, Kulkarni, S., Wei, C., Tang, Y., D'Allura, A., Mena-Carrasco, M., Streets, D. G, Zhang, Q., Pierce, R. B, Al-Saadi, J. A, Emmons, L. K, Pfister, G. G, Avery, M. A, Barrick, J. D, Blake, D. R, Brune, W. H, Cohen, R. C, Dibb, J. E, Fried, A., Heikes, B. G, Huey, L. G, O'Sullivan, D. W, Sachse, G. W, Shetter, R. E, Singh, H. B, Campos, T. L, Cantrell, C. A, Flocke, F. M, Dunlea, E. J, Jimenez, J. L, Weinheimer, A. J, Crounse, J. D, Wennberg, P. O, Schauer, J. J, Stone, E. A, Jaffe, D. A, and Reidmiller, D. R

Subjects
long-range transport, north-america, transpacific transport, pollution transport, asian aerosols, air-pollution, mineral dust, organic mass, emissions, aircraft
Abstract

The Sulfur Transport and dEposition Model (STEM) is applied to the analysis of observations obtained during the Intercontinental Chemical Transport Experiment-Phase B (INTEX-B), conducted over the eastern Pacific Ocean during spring 2006. Predicted trace gas and aerosol distributions over the Pacific are presented and discussed in terms of transport and source region contributions. Trace species distributions show a strong west (high) to east (low) gradient, with the bulk of the pollutant transport over the central Pacific occurring between similar to 20 degrees N and 50 degrees N in the 2-6 km altitude range. These distributions are evaluated in the eastern Pacific by comparison with the NASA DC-8 and NSF/NCAR C-130 airborne measurements along with observations from the Mt. Bachelor (MBO) surface site. Thirty different meteorological, trace gas and aerosol parameters are compared. In general the meteorological fields are better predicted than gas phase species, which in turn are better predicted than aerosol quantities. PAN is found to be significantly overpredicted over the eastern Pacific, which is attributed to uncertainties in the chemical reaction mechanisms used in current atmospheric chemistry models in general and to the specifically high PAN production in the SAPRC-99 mechanism used in the regional model. A systematic underprediction of the elevated sulfate layer in the eastern Pacific observed by the C-130 is another issue that is identified and discussed. Results from source region tagged CO simulations are used to estimate how the different source regions around the Pacific contribute to the trace gas species distributions. During this period the largest contributions were from China and from fires in South/Southeast and North Asia. For the C-130 flights, which operated off the coast of the Northwest US, the regional CO contributions range as follows: China (35%), South/Southeast Asia fires (35%), North America anthropogenic (20%), and North Asia fires (10%). The transport of pollution into the western US is studied at MBO and a variety of events with elevated Asian dust, and periods with contributions from China and fires from both Asia and North America are discussed. The role of heterogeneous chemistry on the composition over the eastern Pacific is also studied. The impacts of heterogeneous reactions at specific times can be significant, increasing sulfate and nitrate aerosol production and reducing gas phase nitric acid levels appreciably (similar to 50%).

Published
2010

2. Observations of heterogeneous reactions between Asian pollution and mineral dust over the Eastern North Pacific during INTEX-B

Author

McNaughton, C. S, Clarke, A. D, Kapustin, V., Shinozuka, Y., Howell, S. G, Anderson, B. E, Winstead, E., Dibb, J., Scheuer, E., Cohen, R. C, Wooldridge, P., Perring, A., Huey, L. G, Kim, S., Jimenez, J. L, Dunlea, E. J, DeCarlo, P. F, Wennberg, P. O, Crounse, J. D, Weinheimer, A. J, and Flocke, F.

Subjects
aerodynamic diameter measurements, aerosol mass-spectrometry, sea-salt aerosols, optical-properties, Mexico-City, radiative properties, size distribution, ACE-ASIA, density characterization, tropospheric chemistry
Abstract

In-situ airborne measurements of trace gases, aerosol size distributions, chemistry and optical properties were conducted over Mexico and the Eastern North Pacific during MILAGRO and INTEX-B. Heterogeneous reactions between secondary aerosol precursor gases and mineral dust lead to sequestration of sulfur, nitrogen and chlorine in the supermicrometer particulate size range. Simultaneous measurements of aerosol size distributions and weak-acid soluble calcium result in an estimate of 11 wt% of CaCO3 for Asian dust. During transport across the North Pacific, ~5–30% of the CaCO3 is converted to CaSO4 or Ca(NO3)2 with an additional ~4% consumed through reactions with HCl. The 1996 to 2008 record from the Mauna Loa Observatory confirm these findings, indicating that, on average, 19% of the CaCO3 has reacted to form CaSO4 and 7% has reacted to form Ca(NO3)2 and ~2% has reacted with HCl. In the nitrogen-oxide rich boundary layer near Mexico City up to 30% of the CaCO3 has reacted to form Ca(NO3)2while an additional 8% has reacted with HCl. These heterogeneous reactions can result in a ~3% increase in dust solubility which has an insignificant effect on their optical properties compared to their variability in-situ. However, competition between supermicrometer dust and submicrometer primary aerosol for condensing secondary aerosol species led to a 25% smaller number median diameter for the accumulation mode aerosol. A 10–25% reduction of accumulation mode number median diameter results in a 30–70% reduction in submicrometer light scattering at relative humidities in the 80–95% range. At 80% RH submicrometer light scattering is only reduced ~3% due to a higher mass fraction of hydrophobic refractory components in the dust-affected accumulation mode aerosol. Thus reducing the geometric mean diameter of the submicrometer aerosol has a much larger effect on aerosol optical properties than changes to the hygroscopic:hydrophobic mass fractions of the accumulation mode aerosol. In the presence of dust, nitric acid concentrations are reduced to 85% to 60–80% in the presence of dust. These observations support previous model studies which predict irreversible sequestration of reactive nitrogen species through heterogeneous reactions with mineral dust during long-range transport.

Published
2009

3. Total observed organic carbon (TOOC) in the atmosphere: a synthesis of North American observations

Author

Heald, C. L, Goldstein, A. H, Allan, J. D, Aiken, A. C, Apel, E., Atlas, E. L, Baker, A. K, Bates, T. S, Beyersdorf, A. J, Blake, D. R, Campos, T., Coe, H., Crounse, J. D, DeCarlo, P. F, de Gouw, J. A, Dunlea, E. J, Flocke, F. M, Fried, A., Goldan, P., Griffin, R. J, Herndon, S. C, Holloway, J. S, Holzinger, R., Jimenez, J. L, Junkermann, W., Kuster, W. C, Lewis, A. C, Meinardi, S., Millet, D. B, Onasch, T., Polidori, A., Quinn, P. K, Riemer, D. D, Roberts, J. M, Salcedo, D., Sive, B., Swanson, A. L, Talbot, R., Warneke, C., Weber, R. J, Weibring, P., Wennberg, P. O, Worsnop, D. R, Wittig, A. E, Zhang, R., Zheng, J., and Zheng, W.

Subjects
reaction mass-spectrometry, air-quality, nonmethane hydrocarbons, new-england, in-situ, aerosol, formaldehyde, emissions, troposphere, pittsburgh
Abstract

Measurements of organic carbon compounds in both the gas and particle phases made upwind, over and downwind of North America are synthesized to examine the total observed organic carbon (TOOC) in the atmosphere over this region. These include measurements made aboard the NOAA WP-3 and BAe-146 aircraft, the NOAA research vessel Ronald H. Brown, and at the Thompson Farm and Chebogue Point surface sites during the summer 2004 ICARTT campaign. Both winter and summer 2002 measurements during the Pittsburgh Air Quality Study are also included. Lastly, the spring 2002 observations at Trinidad Head, CA, surface measurements made in March 2006 in Mexico City and coincidentally aboard the C-130 aircraft during the MILAGRO campaign and later during the IMPEX campaign off the northwestern United States are incorporated. Concentrations of TOOC in these datasets span more than two orders of magnitude. The daytime mean TOOC ranges from 4.0 to 456 mu gCm(-3) from the cleanest site (Trinidad Head) to the most polluted (Mexico City). Organic aerosol makes up 3-17% of this mean TOOC, with highest fractions reported over the northeastern United States, where organic aerosol can comprise up to 50% of TOOC. Carbon monoxide concentrations explain 46 to 86% of the variability in TOOC, with highest TOOC/CO slopes in regions with fresh anthropogenic influence, where we also expect the highest degree of mass closure for TOOC. Correlation with isoprene, formaldehyde, methyl vinyl ketone and methacrolein also indicates that biogenic activity contributes substantially to the variability of TOOC, yet these tracers of biogenic oxidation sources do not explain the variability in organic aerosol observed over North America. We highlight the critical need to develop measurement techniques to routinely detect total gas phase VOCs, and to deploy comprehensive suites of TOOC instruments in diverse environments to quantify the ambient evolution of organic carbon from source to sink.

Published
2008

4. Evolution of Organic Aerosols in the Atmosphere

Author

Jimenez, J. L., Canagaratna, M. R., Donahue, N. M., Prevot, A. S. H., Zhang, Q., Kroll, J. H., DeCarlo, P. F., Allan, J. D., Coe, H., Ng, N. L., Aiken, A. C., Docherty, K. S., Ulbrich, I. M., Grieshop, A. P., Robinson, A. L., Duplissy, J., Smith, J. D., Wilson, K. R., Lanz, V. A., Hueglin, C., Sun, Y. L., Tian, J., Laaksonen, A., Raatikainen, T., Rautiainen, J., Vaattovaara, P., Ehn, M., Kulmala, M., Tomlinson, J. M., Collins, D. R., Cubison, M. J., Dunlea, E. J., Huffman, J. A., Onasch, T. B., Alfarra, M. R., Williams, P. I., Bower, K., Kondo, Y., Schneider, J., Drewnick, F., Borrmann, S., Weimer, S., Demerjian, K., Salcedo, D., Cottrell, L., Griffin, R., Takami, A., Miyoshi, T., Hatakeyama, S., Shimono, A., Sun, J. Y., Zhang, Y. M., Dzepina, K., Kimmel, J. R., Sueper, D., Jayne, J. T., Herndon, S. C., Trimborn, A. M., Williams, L. R., Wood, E. C., Middlebrook, A. M., Kolb, C. E., Baltensperger, U., and Worsnop, D. R.

Published
2009
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5. Fast Airborne Aerosol Size and Chemistry Measurements with the High Resolution Aerosol Mass Spectrometer during the MILAGRO Campaign

Author

DeCarlo, P. F, Dunlea, E. J, Kimmel, J. R, Aiken, A. C, Sueper, D, Crounse, J, Wennberg, P. O, Emmons, L, Shinozuka, Y, Clarke, A, Zhou, J, Tomlinson, J, Collins,D. R, Knapp, D, Weinheimer, A. J, Montzka,D. D, Campos,T, and Jimenez, J. L

Subjects
Environment Pollution
Abstract

The concentration, size, and composition of non-refractory submicron aerosol (NR-PM(sub l)) was measured over Mexico City and central Mexico with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) onboard the NSF/NCAR C-130 aircraft as part of the MILAGRO field campaign. This was the first aircraft deployment of the HR-ToF-AMS. During the campaign the instrument performed very well, and provided 12 s data. The aerosol mass from the AMS correlates strongly with other aerosol measurements on board the aircraft. Organic aerosol (OA) species dominate the NR-PM(sub l) mass. OA correlates strongly with CO and HCN indicating that pollution (mostly secondary OA, SOA) and biomass burning (BB) are the main OA sources. The OA to CO ratio indicates a typical value for aged air of around 80 microg/cubic m (STP) ppm(exp -1). This is within the range observed in outflow from the Northeastern US, which could be due to a compensating effect between higher BB but lower biogenic VOC emissions during this study. The O/C atomic ratio for OA is calculated from the HR mass spectra and shows a clear increase with photochemical age, as SOA forms rapidly and quickly overwhelms primary urban OA, consistent with Volkamer et al. (2006) and Kleinman et al. (2008). The stability of the OA/CO while O/C increases with photochemical age implies a net loss of carbon from the OA. BB OA is marked by signals at m/z 60 and 73, and also by a signal enhancement at large m/z indicative of larger molecules or more resistance to fragmentation. The main inorganic components show different spatial patterns and size distributions. Sulfate is regional in nature with clear volcanic and petrochemical/power plant sources, while the urban area is not a major regional source for this species. Nitrate is enhanced significantly in the urban area and immediate outflow, and is strongly correlated with CO indicating a strong urban source. The importance of nitrate decreases with distance from the city likely due to evaporation. BB does not appear to be a strong source of nitrate despite its high emissions of nitrogen oxides, presumably due to low ammonia emissions. NR-chloride often correlates with HCN indicating a fire source, although other sources likely contribute as well. This is the first aircraft study of the regional evolution of aerosol chemistry from a tropical megacity.

Published
2007

6. Total Observed Organic Carbon (TOOC): A Synthesis of North American Observations

Author

Heald, C. L, Goldstein, A. H, Allan, J. D, Aiken, A. C, Apel, E, Atlas, E. L, Baker, A. K, Bates, T. S, Beyersdorf, A. J, Blake, D. R, Campos, T, Coe, H, Crounse, J. D, DeCarlo, P. F, de Gouw, J. A, Dunlea, E. J, Flocke, F. M, Fried, A, Goldan, P, Griffin, R. J, Herndon, S. C, Holloway, J. S, Holzinger, R, Jimenez, J. L, and Junkermann, W

Subjects
Environment Pollution
Abstract

Measurements of organic carbon compounds in both the gas and particle phases made upwind, over and downwind of North America are synthesized to examine the total observed organic carbon (TOOC) in the atmosphere over this region. These include measurements made aboard the NOAA WP-3 and BAe-146 aircraft, the NOAA research vessel Ronald H. Brown, and at the Thompson Farm and Chebogue Point surface sites during the summer 2004 ICARTT campaign. Both winter and summer 2002 measurements during the Pittsburgh Air Quality Study are also included. Lastly, the spring 2002 observations at Trinidad Head, CA, surface measurements made in March 2006 in Mexico City and coincidentally aboard the C-130 aircraft during the MILAGRO campaign and later during the IMPEX campaign off the northwestern United States are incorporated. Concentrations of TOOC in these datasets span more than two orders of magnitude. The daytime mean TOOC ranges from 4.0 to 456 microg C/cubic m from the cleanest site (Trinidad Head) to the most polluted (Mexico City). Organic aerosol makes up 3-17% of this mean TOOC, with highest fractions reported over the northeastern United States, where organic aerosol can comprise up to 50% of TOOC. Carbon monoxide concentrations explain 46 to 86% of the variability in TOOC, with highest TOOC/CO slopes in regions with fresh anthropogenic influence, where we also expect the highest degree of mass closure for TOOC. Correlation with isoprene, formaldehyde, methyl vinyl ketone and methacrolein also indicates that biogenic activity contributes substantially to the variability of TOOC, yet these tracers of biogenic oxidation sources do not explain the variability in organic aerosol observed over North America. We highlight the critical need to develop measurement techniques to routinely detect total gas phase VOCs, and to deploy comprehensive suites of TOOC instruments in diverse environments to quantify the ambient evolution of organic carbon from source to sink.

Published
2007

7. Analysis of aircraft and satellite measurements from the Intercontinental Chemical Transport Experiment (INTEX-B) to quantify long-range transport of East Asian sulfur to Canada

Author

Donkelaar, A., Randall Martin, Leaitch, W. R., Macdonald, A. M., Walker, T. W., Streets, D. G., Zhang, Q., Dunlea, E. J., Jimenez, J. L., Dibb, J. E., Huey, L. G., Weber, R., Andreae, M. O., Department of Physics and Atmospheric Science [Halifax], Dalhousie University [Halifax], Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University [Cambridge]-Smithsonian Institution, Science and Technology Branch, Dept. of Physics, Decision and Information Sciences Division, Department of Chemistry and Biochemistry, EOS Climate Change Research Center [Durham], Institute for the Study of Earth, Oceans, and Space [Durham] (EOS), University of New Hampshire (UNH)-University of New Hampshire (UNH), School of Earth and Atmospheric Sciences [Atlanta], Georgia Institute of Technology [Atlanta], Biogeochemistry Department [Mainz], Max Planck Institute for Chemistry (MPIC), Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, and EGU, Publication

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, lcsh:Chemistry, 010504 meteorology & atmospheric sciences, lcsh:QD1-999, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, 13. Climate action, 010501 environmental sciences, 01 natural sciences, lcsh:Physics, lcsh:QC1-999, 0105 earth and related environmental sciences
Abstract

We interpret a suite of satellite, aircraft, and ground-based measurements over the North Pacific Ocean and western North America during April–May 2006 as part of the Intercontinental Chemical Transport Experiment Phase B (INTEX-B) campaign to understand the implications of long-range transport of East Asian emissions to North America. The Canadian component of INTEX-B included 33 vertical profiles from a Cessna 207 aircraft equipped with an aerosol mass spectrometer. Long-range transport of organic aerosols was insignificant, contrary to expectations. Measured sulfate plumes in the free troposphere over British Columbia exceeded 2 μg/m3. We update the global anthropogenic emission inventory in a chemical transport model (GEOS-Chem) and use it to interpret the observations. Aerosol Optical Depth (AOD) retrieved from two satellite instruments (MISR and MODIS) for 2000–2006 are analyzed with GEOS-Chem to estimate an annual growth in Chinese sulfur emissions of 6.2% and 9.6%, respectively. Analysis of aircraft sulfate measurements from the NASA DC-8 over the central Pacific, the NSF C-130 over the east Pacific and the Cessna over British Columbia indicates most Asian sulfate over the ocean is in the lower free troposphere (800–600 hPa), with a decrease in pressure toward land due to orographic effects. We calculate that 56% of the measured sulfate between 500–900 hPa over British Columbia is due to East Asian sources. We find evidence of a 72–85% increase in the relative contribution of East Asian sulfate to the total burden in spring off the northwest coast of the United States since 1985. Campaign-average simulations indicate anthropogenic East Asian sulfur emissions increase mean springtime sulfate in Western Canada at the surface by 0.31 μg/m3 (~30%) and account for 50% of the overall regional sulfate burden between 1 and 5 km. Mean measured daily surface sulfate concentrations taken in the Vancouver area increase by 0.32 μg/m3 per 10% increase in the simulated fraction of Asian sulfate, and suggest current East Asian emissions episodically degrade local air quality by more than 1.5 μg/m3.

Published
2008

8. Evaluation of nitrogen dioxide chemiluminescence monitors in a polluted urban environment

Author

Dunlea, E. J., Herndon, S. C., Nelson, D. D., Volkamer, R. M., Federico San Martini, Sheehy, P. M., Zahniser, M. S., Shorter, J. H., Wormhoudt, J. C., Lamb, B. K., Allwine, E. J., Gaffney, J. S., Marley, N. A., Grutter, M., Marquez, C., Blanco, S., Cardenas, B., Retama, A., Yillegas, C. R. R., Kolb, C. E., Molina, L. T., Molina, M. J., Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Aerodyne Research Inc., WSU Laboratory for Atmospheric Research, Washington State University (WSU), University of Arkansas at Little Rock, 2801 South University Avenue, Centro de Ciencias de la Atmysfera, Centro Nacional de Investigacion y Capacitacion Ambiental-INE, Gobierno del Distrito Federal, Molina Center for the Energy and the Environment (MCE2), Centro de Ciencias de la Atmosfera [Mexico], and Universidad Nacional Autónoma de México (UNAM)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, lcsh:Chemistry, 010504 meteorology & atmospheric sciences, lcsh:QD1-999, 13. Climate action, 11. Sustainability, 010501 environmental sciences, 01 natural sciences, lcsh:Physics, lcsh:QC1-999, 0105 earth and related environmental sciences
Abstract

International audience; Data from a recent field campaign in Mexico City are used to evaluate the performance of the EPA Federal Reference Method for monitoring the ambient concentrations of NO2. Measurements of NO2 from standard chemiluminescence monitors equipped with molybdenum oxide converters are compared with those from Tunable Infrared Laser Differential Absorption Spectroscopy (TILDAS) and Differential Optical Absorption Spectroscopy (DOAS) instruments. A significant interference in the chemiluminescence measurement is shown to account for up to 50% of ambient NO2 concentration during afternoon hours. As expected, this interference correlates well with non-NOx reactive nitrogen species (NOz) as well as with ambient O3 concentrations, indicating a photochemical source for the interfering species. A combination of ambient gas phase nitric acid and alkyl and multifunctional alkyl nitrates is deduced to be the primary cause of the interference. Observations at four locations at varying proximities to emission sources indicate that the percentage contribution of HNO3 to the interference decreases with time as the air parcel ages. Alkyl and multifunctional alkyl nitrate concentrations are calculated to reach concentrations as high as several ppb inside the city, on par with the highest values previously observed in other urban locations. Averaged over the MCMA-2003 field campaign, the chemiluminescence monitor interference resulted in an average measured NO2 concentration up to 22% greater than that from co-located spectroscopic measurements. Thus, this interference has the potential to initiate regulatory action in areas that are close to non-attainment and may mislead atmospheric photochemical models used to assess control strategies for photochemical oxidants.

Published
2007

9. Total Observed Organic Carbon (TOOC): A synthesis of North American observations

Author

Heald, C. L., Goldstein, A. H., Allan, J. D., Aiken, A. C., Apel, E., Atlas, E. L., Baker, A. K., Bates, T. S., Beyersdorf, A. J., Blake, D. R., Campos, T., Coe, H., Crounse, J. D., Decarlo, P. F., De Gouw, J. A., Dunlea, E. J., Flocke, F. M., Fried, A., Goldan, P., Griffin, R. J., Herndon, S. C., Holloway, J. S., Holzinger, R., Jimenez, J. L., Junkermann, W., Kuster, W. C., Lewis, A. C., Meinardi, S., Millet, D. B., Onasch, T., Polidori, A., Quinn, P. K., Riemer, D. D., Roberts, J. M., Salcedo, D., Sive, B., Swanson, A. L., Talbot, R., Warneke, C., Weber, R. J., Weibring, P., Wennberg, P. O., Wittig, A. E., Zhang, R., Zheng, J., Zheng, W., Department of Environmental Science and Policy Management, University of California, School of Earth, Atmospheric and Environmental Sciences, Department of Atmospheric and Oceanic Sciences [Boulder] ( ATOC ), University of Colorado Boulder [Boulder], Cooperative Institute for Research in Environmental Sciences ( CIRES ), University of Colorado Boulder [Boulder]-National Oceanic and Atmospheric Administration ( NOAA ), Atmospheric Chemistry Division [Boulder], National Center for Atmospheric Research [Boulder] ( NCAR ), Marine and Atmospheric Chemistry Division [Miami], Rosenstiel School of Marine and Atmospheric Science ( RSMAS ), University of Miami [Coral Gables]-University of Miami [Coral Gables], Department of Chemistry, NOAA Pacific Marine Environmental Laboratory [Seattle] ( PMEL ), National Oceanic and Atmospheric Administration ( NOAA ), California Institute of Technology ( CALTECH ), ESRL Chemical Sciences Division [Boulder] ( CSD ), NOAA Earth System Research Laboratory ( ESRL ), National Oceanic and Atmospheric Administration ( NOAA ) -National Oceanic and Atmospheric Administration ( NOAA ), Institute for Study of Earth, Oceans and Space, University of New Hampshire ( UNH ), Aerodyne Research Inc., Institute for Marine and Atmospheric Research [Utrecht] ( IMAU ), Utrecht University [Utrecht], Forschungszentrum Karlsruhe, Department of Chemistry [York, UK], University of York [York, UK], Department of Soil, Water and Climate, Department of Civil and Environmental Engineering, University of Southern California ( USC ), Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Northrop Grumman Space Technology ( Northrop Grumman Space Technology ), Chemistry Technology Department, School of Earth and Atmospheric Sciences [Atlanta], Georgia Institute of Technology [Atlanta], Department of Civil Engineering, The City College of New York ( CCNY ), City University of New-York [New-York] ( CUNY ) -City University of New-York [New-York] ( CUNY ), Department of Atmospheric Sciences [College Station], Texas A&M University [College Station], Department of Environmental Science, Policy, and Management [Berkeley] (ESPM), University of California [Berkeley], University of California-University of California, School of Earth, Atmospheric and Environmental Sciences [Manchester] (SEAES), University of Manchester [Manchester], Department of Atmospheric and Oceanic Sciences [Boulder] (ATOC), University of Colorado [Boulder], Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado [Boulder]-National Oceanic and Atmospheric Administration (NOAA), National Center for Atmospheric Research [Boulder] (NCAR), Rosenstiel School of Marine and Atmospheric Science (RSMAS), NOAA Pacific Marine Environmental Laboratory [Seattle] (PMEL), National Oceanic and Atmospheric Administration (NOAA), California Institute of Technology (CALTECH), ESRL Chemical Sciences Division [Boulder] (CSD), NOAA Earth System Research Laboratory (ESRL), National Oceanic and Atmospheric Administration (NOAA)-National Oceanic and Atmospheric Administration (NOAA), University of New Hampshire (UNH), Institute for Marine and Atmospheric Research [Utrecht] (IMAU), Department of Soil, Water and Climate, University of Minnesota [Twin Cities] (UMN), University of Minnesota System-University of Minnesota System, University of Southern California (USC), Universidad Autonoma del Estado de Morelos (UAEM), Northrop Grumman Space Technology (Northrop Grumman Space Technology), The City College of New York (CCNY), and City University of New York [New York] (CUNY)-City University of New York [New York] (CUNY)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [ SDU.OCEAN ] Sciences of the Universe [physics]/Ocean, Atmosphere, 010504 meteorology & atmospheric sciences, 13. Climate action, 010501 environmental sciences, 01 natural sciences, Caltech Library Services, 0105 earth and related environmental sciences
Abstract

Measurements of organic carbon compounds in both the gas and particle phases measured upwind, over and downwind of North America are synthesized to examine the total observed organic carbon (TOOC) over this region. These include measurements made aboard the NOAA WP-3 and BAe-146 aircraft, the NOAA research vessel Ronald H. Brown, and at the Thompson Farm and Chebogue Point surface sites during the summer 2004 ICARTT campaign. Both winter and summer 2002 measurements during the Pittsburgh Air Quality Study are also included. Lastly, the spring 2002 observations at Trinidad Head, CA, surface measurements made in March 2006 in Mexico City and coincidentally aboard the C-130 aircraft during the MILAGRO campaign and later during the IMPEX campaign off the northwestern United States are incorporated. Concentrations of TOOC in these datasets span more than two orders of magnitude. The daytime mean TOOC ranges from 4.0 to 456 μgC m−3 from the cleanest site (Trinidad Head) to the most polluted (Mexico City). Organic aerosol makes up 3–17% of this mean TOOC, with highest fractions reported over the northeastern United States, where organic aerosol can comprise up to 50% of TOOC. Carbon monoxide concentrations explain 46 to 86% of the variability in TOOC, with highest TOOC/CO slopes in regions with fresh anthropogenic influence, where we also expect the highest degree of mass closure for TOOC. Correlation with isoprene, formaldehyde, methyl vinyl ketene and methacrolein also indicates that biogenic activity contributes substantially to the variability of TOOC, yet these tracers of biogenic oxidation sources do not explain the variability in organic aerosol observed over North America. We highlight the critical need to develop measurement techniques to routinely detect total gas phase VOCs, and to deploy comprehensive suites of TOOC instruments in diverse environments to quantify the ambient evolution of organic carbon from source to sink.

Published
2007

10. Fast airborne aerosol size and chemistry measurements with the high resolution aerosol mass spectrometer during the MILAGRO Campaign

Author

Decarlo, P. F., Dunlea, E. J., Kimmel, J. R., Aiken, A. C., Sueper, D., Crounse, J., Wennberg, P. O., Emmons, L., Shinozuka, Y., Clarke, A., Zhou, J., Tomlinson, J., Collins, D. R., Knapp, D., Weinheimer, A. J., Montzka, D. D., Campos, T., Jimenez, J. L., and EGU, Publication

Subjects
[SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere
Abstract

The concentration, size, and composition of non-refractory submicron aerosol (NR-PM1) was measured over Mexico City and central Mexico with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) onboard the NSF/NCAR C-130 aircraft as part of the MILAGRO field campaign. This was the first aircraft deployment of the HR-ToF-AMS, in which the instrument performed very well, and provided 12 s data. The aerosol mass from the AMS correlates strongly with other aerosol measurements on board the aircraft. Organic aerosol (OA) species dominate the NR-PM1 mass. OA correlates strongly with CO and HCN indicating that pollution (mostly secondary OA, SOA) and biomass burning (BB) are the main OA sources. The OA to CO ratio indicates a typical value for aged air of around 80 ?g m?3 (STP) ppm?1. This is within the range observed in outflow from the Northeastern US, which could be due to a compensating effect between higher BB but lower biogenic VOC emissions during this study. The O/C atomic ratio for OA is calculated from the HR mass spectra and shows a clear increase with photochemical age, as SOA forms rapidly and quickly overwhelms primary urban OA, consistent with Volkamer et al. (2006) and Kleinman et al. (2007b). BB OA is marked by signals at m/z 60 and 73, and also by a signal enhancement at large m/z indicative of larger molecules or more resistance to fragmentation. The main inorganic components show different spatial patterns and size distributions. Sulfate is regional in nature with clear volcanic and petrochemical/power plant sources, while the urban area is not a major source for this species. Nitrate is enhanced significantly in the urban area and immediate outflow, and is strongly correlated with CO indicating a strong urban source. The importance of nitrate decreases with distance from the city likely due to evaporation. BB does not appear to be a strong source of nitrate despite its high emissions of nitrogen oxides, presumably due to low ammonia emissions. NR-chloride often correlates with HCN indicating a fire source, although other sources likely contribute as well. This is the first aircraft study of the regional evolution of aerosol chemistry from a tropical megacity.

Published
2007

11. Implementation of a Markov Chain Monte Carlo method to inorganic aerosol modeling of observations from the MCMA-2003 campaign ? Part II: Model application to the CENICA, Pedregal and Santa Ana sites

Author

San Martini, F. M., Dunlea, E. J., Volkamer, R., Onasch, T. B., Jayne, J. T., Canagaratna, M. R., Worsnop, D. R., Kolb, C. E., Shorter, J. H., Herndon, S. C., Zahniser, M. S., Salcedo, D., Katja Dzepina, Jimenez, J. L., Ortega, J. M., Johnson, K. S., Mcrae, G. J., Molina, L. T., Molina, M. J., Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado [Boulder]-National Oceanic and Atmospheric Administration (NOAA), Aerodyne Research Inc., Centro de Investigaciones Químicas, Universidad Autonoma del Estado de Morelos (UAEM), Department of Chemistry and Biochemistry [Boulder], University of Colorado [Boulder], Department of Chemical Engineering, Massachusetts Institute of Technology (MIT), Molina Center on Energy and the Environment, and EGU, Publication

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 13. Climate action, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere
Abstract

International audience; A Markov Chain Monte Carlo model for integrating the observations of inorganic species with a thermodynamic equilibrium model was presented in Part I of this series. Using observations taken at three ground sites, i.e. a residential, industrial and rural site, during the MCMA-2003 campaign in Mexico City, the model is used to analyze the inorganic particle and ammonia data and to predict gas phase concentrations of nitric and hydrochloric acid. In general, the model is able to accurately predict the observed inorganic particle concentrations at all three sites. The agreement between the predicted and observed gas phase ammonia concentration is excellent. The NOz concentration calculated from the NOy, NO and NO2 observations is of limited use in constraining the gas phase nitric acid concentration given the large uncertainties in this measure of nitric acid and additional reactive nitrogen species. Focusing on the acidic period of 9?11 April identified by Salcedo et al. (2006), the model accurately predicts the particle phase observations during this period with the exception of the nitrate predictions after 10:00 a.m. (Central Daylight Time, CDT) on 9 April, where the model underpredicts the observations by, on average, 20%. This period had a low planetary boundary layer, very high particle concentrations, and higher than expected nitrogen dioxide concentrations. For periods when the particle chloride observations are consistently above the detection limit, the model is able to both accurately predict the particle chloride mass concentrations and provide well-constrained HCl (g) concentrations. The availability of gas-phase ammonia observations helps constrain the predicted HCl (g) concentrations. When the particles are aqueous, the most likely concentrations of HCl (g) are in the sub-ppbv range. The most likely predicted concentration of HCl (g) was found to reach concentrations of order 10 ppbv if the particles are dry. Finally, the atmospheric relevance of HCl (g) is discussed in terms of its indicator properties for the possible influence of chlorine-mediated photochemistry in Mexico City.

Published
2006

12. Technical note: Evaluation of standard ultraviolet absorption ozone monitors in a polluted urban environment

Author

Dunlea, E. J., Herndon, S. C., Nelson, D. D., Volkamer, R. M., Lamb, B. K., Allwine, E. J., Grutter, M., Ramos Villegas, C. R., Marquez, C., Blanco, Stéphane, Cardenas, B., Kolb, C. E., Molina, L. T., Molina, M. J., Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Aerodyne Research Inc., WSU Laboratory for Atmospheric Research, Washington State University (WSU), Centro de Ciencias de la Atmera, UNAM, Gobierno del Distrito Federal, Centro Nacional de Investigacion y Capacitacion Ambiental-INE, Centro de Ciencias de la Atmosfera [Mexico], and Universidad Nacional Autónoma de México (UNAM)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 010504 meteorology & atmospheric sciences, 13. Climate action, 11. Sustainability, 01 natural sciences, 0105 earth and related environmental sciences
Abstract

International audience; The performance of the EPA Federal Equivalent Method (FEM) technique for monitoring ambient concentrations of O3 via ultraviolet absorption (UV) has been evaluated using data from the Mexico City Metropolitan Area (MCMA-2003) field campaign. Comparisons of UV O3 monitors with open path Differential Optical Absorption Spectroscopy (DOAS) and open path Fourier Transform Infrared (FTIR) spectroscopy instruments in two locations revealed average discrepancies in the measured concentrations of +13% to ?10%. Excellent agreement of two separate open path DOAS measurements at one location indicated that spatial and temporal inhomogeneities were not substantially influencing comparisons of the point sampling and open path instruments. The poor agreement between the UV O3 monitors and the open path instruments was attributed to incorrect calibration factors for the UV monitors, although interferences could not be completely ruled out. Applying a linear correction to these calibration factors results in excellent agreement of the UV O3 monitors with the co-located open path measurements; regression slopes were 0.94 to 1.04 and associated R2 values were >0.89. A third UV O3 monitor suffered from large spurious interferences, which were attributed to extinction of UV radiation within the monitor by fine particles (3 monitors and recommendations for future testing are made.

Published
2006

13. Mobile laboratory measurements of black carbon, polycyclic aromatic hydrocarbons and other vehicle emissions in Mexico City

Author

Jiang, M., Marr, L. C., Dunlea, E. J., Herndon, S. C., Jayne, J. T., Kolb, C. E., Knighton, W. B., Rogers, T. M., Zavala, M., Molina, L. T., Molina, M. J., and EGU, Publication

Subjects
[SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere
Abstract

Black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) are of concern due to their effects on climate and health. The main goal of this research is to provide the first estimate of emissions of BC and particle-phase PAHs (PPAHs) from motor vehicles in Mexico City. The emissions of other pollutants including carbon monoxide (CO), oxides of nitrogen (NOx), volatile organic compounds (VOCs), and particulate matter of diameter 2.5 µm and less (PM2.5) are also estimated. As a part of the Mexico City Metropolitan Area field campaign in April 2003 (MCMA-2003), a mobile laboratory was driven throughout the city. The laboratory was equipped with a comprehensive suite of gas and particle analyzers, including an aethalometer that measured BC and a photoionization aerosol sensor that measured PPAHs. While driving through traffic, the mobile lab is continuously sampling exhaust plumes from the vehicles around it. We have developed a method of automatically identifying exhaust plumes, which are then used as the basis for calculation of fleet-average emission factors. In the approximately 75 h of on-road sampling during the field campaign, we have identified ~30 000 exhaust measurement points that represent a variety of vehicle types and driving conditions. The large sample provides a basis for estimating fleet-average emission factors and thus the emission inventory. Motor vehicles in the Mexico City area are estimated to emit 1700±200 metric tons BC, 57±6 tons PPAHs, 1 190 000±40 000 tons CO, 120 000±3000 tons NOx, 202 000±4000 tons VOCs, and 4400±400 tons PM2.5 per year, not including cold start emissions. The estimates for CO, NOx, and PPAHs may be low by up to 10% due to the slower response time of analyzers used to measure these species. Compared to the government's official motor vehicle emission inventory for the year 2002, the estimates for CO, NOx, VOCs, and PM2.5 are 38% lower, 23% lower, 7% higher, and 26% higher, respectively. The distributions of emission factors of BC, PPAHs, and PM2.5 are highly skewed, i.e. asymmetric, while those for benzene, measured as a surrogate for total VOCs, and NOx are less skewed. As a result, the total emissions of BC, PPAHs, and PM2.5 could be reduced by approximately 50% if the highest 20% of data points were removed, but ''super polluters'' are less influential on overall NOx and VOC emissions.

Published
2005

14. Redetermination of the rate coefficient for the reaction of O( 1 D) with N 2

Author

Ravishankara, A., Dunlea, E. J., Blitz, M. A., Dillon, T. J., Heard, D. E., Pilling, M. J., Strekowski, R. S., Nicovich, J. M., Wine, P. H., Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), Max Planck Institute for Chemistry (MPIC), Max-Planck-Gesellschaft, Department of Chemistry, School of Chemistry [Leeds], University of Leeds, Laboratoire Chimie de l'environnement (LCE), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC), and Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM.ANAL]Chemical Sciences/Analytical chemistry, [CHIM]Chemical Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2002
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15. Vehicle fleet emissions of black carbon, polycyclic aromatic hydrocarbons, and other pollutants measured by a mobile laboratory in Mexico City

Author

Civil and Environmental Engineering, Jiang, M., Marr, Linsey C., Dunlea, E. J., Herndon, S. C., Jayne, John T., Kolb, C. E., Knighton, W. B., Rogers, T. M., Zavala, M., Molina, L. T., Molina, M. J., Civil and Environmental Engineering, Jiang, M., Marr, Linsey C., Dunlea, E. J., Herndon, S. C., Jayne, John T., Kolb, C. E., Knighton, W. B., Rogers, T. M., Zavala, M., Molina, L. T., and Molina, M. J.

Abstract

Black carbon ( BC) and polycyclic aromatic hydrocarbons (PAHs) are of concern due to their effects on climate and health. The main goal of this research is to provide the first estimate of emissions of BC and particle-phase PAHs (PPAHs) from motor vehicles in Mexico City. The emissions of other pollutants including carbon monoxide ( CO), oxides of nitrogen (NOx), volatile organic compounds (VOCs), and particulate matter of diameter 2.5 mu m and less (PM2.5) are also estimated. As a part of the Mexico City Metropolitan Area field campaign in April 2003 (MCMA-2003), a mobile laboratory was driven throughout the city. The laboratory was equipped with a comprehensive suite of gas and particle analyzers, including an aethalometer that measured BC and a photoionization aerosol sensor that measured PPAHs. While driving through traffic, the mobile lab continuously sampled exhaust plumes from the vehicles around it. We have developed a method of automatically identifying exhaust plumes, which are then used as the basis for calculation of fleet-average emissions. In the approximately 75 h of on-road sampling during the field campaign, we have identified similar to 30 000 exhaust measurement points that represent a variety of vehicle types and driving conditions. The large sample provides a basis for estimating fleet-average emission factors and thus the emission inventory. Motor vehicles in the Mexico City area are estimated to emit 1700 +/- 200 metric tons BC, 57 +/- 6 tons PPAHs, 1 190 000 +/- 40 000 tons CO, 120 000 +/- 3000 tons NOx, 240 000 +/- 50 000 tons VOCs, and 4400 +/- 400 tons PM2.5 per year, not including cold start emissions. The estimates for CO, NOx, and PPAHs may be low by up to 10% due to the slower response time of analyzers used to measure these species. Compared to the government's official motor vehicle emission inventory for the year 2002, the estimates for CO, NOx, VOCs, and PM2.5 are 38% lower, 23% lower, 27% higher, and 25% higher, respectively. The

Published
2005

16. Changes in the photochemical environment of the temperate North Pacific troposphere in response to increased Asian emissions

Author

Parrish, D. D., Parrish, D. D., Dunlea, E. J., Atlas, E. L., Schauffler, S., Donnelly, S., Stroud, V., Goldstein, A. H., Millet, D. B., McKay, M., Jaffe, D. A., Price, H. U., Hess, P. G., Flocke, F., Roberts, J. M., Parrish, D. D., Parrish, D. D., Dunlea, E. J., Atlas, E. L., Schauffler, S., Donnelly, S., Stroud, V., Goldstein, A. H., Millet, D. B., McKay, M., Jaffe, D. A., Price, H. U., Hess, P. G., Flocke, F., and Roberts, J. M.

Abstract

Measurements during the Intercontinental Transport and Chemical Transformation 2002 (ITCT 2K2) field study characterized the springtime, eastern Pacific ozone distribution at two ground sites, from the National Oceanic and Atmospheric Administration WP-3D aircraft, and from a light aircraft operated by the University of Washington. D. Jaffe and colleagues compared the 2002 ozone distribution with measurements made in the region over the two previous decades and show that average ozone levels over the eastern midlatitude Pacific have systematically increased by ∼10 ppbv in the last two decades. Here we provide substantial evidence that a marked change in the photochemical environment in the springtime troposphere of the North Pacific is responsible for this increased O3. This change is evidenced in the eastern North Pacific ITCT 2K2 study region by (1) larger increases in the minimum observed ozone levels compared to more modest increases in the maximum levels, (2) increased peroxyacetyl nitrate (PAN) levels that parallel trends in NOx, emissions, and (3) decreased efficiency of photochemical O3 destruction, i.e., less negative O3 photochemical tendency (or net rate of O3 photochemical production; P(O3)). This change photochemical environment is hypothesized to be due to anthropogenic emissions from Asia, which are believed to have substantially increased over the two decades preceding the study. We propose that their influence has changed the springtime Pacific tropospheric photochemistry from predominately ozone destroying to more nearly ozone producing. However, chemical transport model calculations indicate the possible influence of a confounding factor; unusual transport of tropical air to the western North Pacific during one early field study may have played a role in this apparent change in the photochemistry. Copyright 2004 by the American Geophysical Union.

Published
2004

17. Exploring the vertical profile of atmospheric organic aerosol: comparing 17 aircraft field campaigns with a global model

Author

Heald, C. L., primary, Coe, H., additional, Jimenez, J. L., additional, Weber, R. J., additional, Bahreini, R., additional, Middlebrook, A. M., additional, Russell, L. M., additional, Jolleys, M., additional, Fu, T.-M., additional, Allan, J. D., additional, Bower, K. N., additional, Capes, G., additional, Crosier, J., additional, Morgan, W. T., additional, Robinson, N. H., additional, Williams, P. I., additional, Cubison, M. J., additional, DeCarlo, P. F., additional, and Dunlea, E. J., additional

Published
2011
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18. Supplementary material to "Exploring the vertical profile of atmospheric organic aerosol: comparing 17 aircraft field campaigns with a global model"

Author

Heald, C. L., primary, Coe, H., additional, Jimenez, J. L., additional, Weber, R. J., additional, Bahreini, R., additional, Middlebrook, A. M., additional, Russell, L. M., additional, Jolleys, M., additional, Fu, T.-M., additional, Allan, J. D., additional, Bower, K. N., additional, Capes, G., additional, Crosier, J., additional, Morgan, W. T., additional, Robinson, N. H., additional, Williams, P. I., additional, Cubison, M. J., additional, DeCarlo, P. F., additional, and Dunlea, E. J., additional

Published
2011
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19. Importance of secondary sources in the atmospheric budgets of formic and acetic acids

Author

Paulot, F., primary, Wunch, D., additional, Crounse, J. D., additional, Toon, G. C., additional, Millet, D. B., additional, DeCarlo, P. F., additional, Vigouroux, C., additional, Deutscher, N. M., additional, González Abad, G., additional, Notholt, J., additional, Warneke, T., additional, Hannigan, J. W., additional, Warneke, C., additional, de Gouw, J. A., additional, Dunlea, E. J., additional, De Mazière, M., additional, Griffith, D. W. T., additional, Bernath, P., additional, Jimenez, J. L., additional, and Wennberg, P. O., additional

Published
2011
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20. Importance of secondary sources in the atmospheric budgets of formic and acetic acids

Author

Paulot, F., primary, Wunch, D., additional, Crounse, J. D., additional, Toon, G. C., additional, Millet, D. B., additional, DeCarlo, P. F., additional, Vigouroux, C., additional, Deutscher, N. M., additional, González Abad, G., additional, Notholt, J., additional, Warneke, T., additional, Hannigan, J. W., additional, Warneke, C., additional, de Gouw, J. A., additional, Dunlea, E. J., additional, De Mazière, M., additional, Griffith, D. W. T., additional, Bernath, P., additional, Jimenez, J. L., additional, and Wennberg, P. O., additional

Published
2010
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21. Supplementary material to "Importance of secondary sources in the atmospheric budgets of formic and acetic acids"

Author

Paulot, F., primary, Wunch, D., additional, Crounse, J. D., additional, Toon, G. C., additional, Millet, D. B., additional, DeCarlo, P. F., additional, Vigouroux, C., additional, Deutscher, N. M., additional, González Abad, G., additional, Notholt, J., additional, Warneke, T., additional, Hannigan, J. W., additional, Warneke, C., additional, de Gouw, J. A., additional, Dunlea, E. J., additional, De Mazière, M., additional, Griffith, D. W. T., additional, Bernath, P., additional, Jimenez, J. L., additional, and Wennberg, P. O., additional

Published
2010
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24. Supplementary material to "Investigation of the sources and processing of organic aerosol over the Central Mexican Plateau from aircraft measurements during MILAGRO"

Author

DeCarlo, P. F., primary, Ulbrich, I. M., additional, Crounse, J., additional, de Foy, B., additional, Dunlea, E. J., additional, Aiken, A. C., additional, Knapp, D., additional, Weinheimer, A. J., additional, Campos, T., additional, Wennberg, P. O., additional, and Jimenez, J. L., additional

Published
2010
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25. Evolution of Asian aerosols during transpacific transport in INTEX-B

Author

Dunlea, E. J., primary, DeCarlo, P. F., additional, Aiken, A. C., additional, Kimmel, J. R., additional, Peltier, R. E., additional, Weber, R. J., additional, Tomlinson, J., additional, Collins, D. R., additional, Shinozuka, Y., additional, McNaughton, C. S., additional, Howell, S. G., additional, Clarke, A. D., additional, Emmons, L. K., additional, Apel, E. C., additional, Pfister, G. G., additional, van Donkelaar, A., additional, Martin, R. V., additional, Millet, D. B., additional, Heald, C. L., additional, and Jimenez, J. L., additional

Published
2009
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26. Aerosol optical properties relevant to regional remote sensing of CCN activity and links to their organic mass fraction: airborne observations over Central Mexico and the US West Coast during MILAGRO/INTEX-B

Author

Shinozuka, Y., primary, Clarke, A. D., additional, DeCarlo, P. F., additional, Jimenez, J. L., additional, Dunlea, E. J., additional, Roberts, G. C., additional, Tomlinson, J. M., additional, Collins, D. R., additional, Howell, S. G., additional, Kapustin, V. N., additional, McNaughton, C. S., additional, and Zhou, J., additional

Published
2009
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27. Supplementary material to "Trans-Pacific transport and evolution of aerosols and trace gases from Asia during the INTEX-B field campaign"

Author

Adhikary, B., primary, Carmichael, G. R., additional, Kulkarni, S., additional, Wei, C., additional, Tang, Y., additional, Dallura, A., additional, Mena-Carrasco, M., additional, Streets, D. G., additional, Zhang, Q., additional, Pierce, R. B., additional, Al-Saadi, J. A., additional, Emmons, L. K., additional, Pfister, G. G., additional, Avery, M. A., additional, Barrick, J. D., additional, Blake, D. R., additional, Brune, W. H., additional, Cohen, R. C., additional, Dibb, J. E., additional, Fried, A., additional, Heikes, B. G., additional, Huey, L. G., additional, O'Sullivan, D. W., additional, Sachse, G. W., additional, Shetter, R. E., additional, Singh, H. B., additional, Campos, T. L., additional, Cantrell, C. A., additional, Flocke, F. M., additional, Dunlea, E. J., additional, Jimenez, J. L., additional, Weinheimer, A. J., additional, Crounse, J. D., additional, Wennberg, P. O., additional, Schauer, J. J., additional, Stone, E. A., additional, Jaffe, D. A., additional, and Reidmiller, D. R., additional

Published
2009
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28. Trans-Pacific transport and evolution of aerosols and trace gases from Asia during the INTEX-B field campaign

Author

Adhikary, B., primary, Carmichael, G. R., additional, Kulkarni, S., additional, Wei, C., additional, Tang, Y., additional, Dallura, A., additional, Mena-Carrasco, M., additional, Streets, D. G., additional, Zhang, Q., additional, Pierce, R. B., additional, Al-Saadi, J. A., additional, Emmons, L. K., additional, Pfister, G. G., additional, Avery, M. A., additional, Barrick, J. D., additional, Blake, D. R., additional, Brune, W. H., additional, Cohen, R. C., additional, Dibb, J. E., additional, Fried, A., additional, Heikes, B. G., additional, Huey, L. G., additional, O'Sullivan, D. W., additional, Sachse, G. W., additional, Shetter, R. E., additional, Singh, H. B., additional, Campos, T. L., additional, Cantrell, C. A., additional, Flocke, F. M., additional, Dunlea, E. J., additional, Jimenez, J. L., additional, Weinheimer, A. J., additional, Crounse, J. D., additional, Wennberg, P. O., additional, Schauer, J. J., additional, Stone, E. A., additional, Jaffe, D. A., additional, and Reidmiller, D. R., additional

Published
2009
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30. Supplementary material to "Aerosol optical properties relevant to regional remote sensing of CCN activity and links to their organic mass fraction: airborne observations over Central Mexico and the US West Coast during MILAGRO/INTEX-B"

Author

Shinozuka, Y., primary, Clarke, A. D., additional, DeCarlo, P. F., additional, Jimenez, J. L., additional, Dunlea, E. J., additional, Roberts, G. C., additional, Tomlinson, J. M., additional, Collins, D. R., additional, Howell, S. G., additional, Kapustin, V. N., additional, McNaughton, C. S., additional, and Zhou, J., additional

Published
2009
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31. Observations of heterogeneous reactions between Asian pollution and mineral dust over the Eastern North Pacific during INTEX-B

Author

McNaughton, C. S., primary, Clarke, A. D., additional, Kapustin, V., additional, Shinozuka, Y., additional, Howell, S. G., additional, Anderson, B. E., additional, Winstead, E., additional, Dibb, J., additional, Scheuer, E., additional, Cohen, R. C., additional, Wooldridge, P., additional, Perring, A., additional, Huey, L. G., additional, Kim, S., additional, Jimenez, J. L., additional, Dunlea, E. J., additional, DeCarlo, P. F., additional, Wennberg, P. O., additional, Crounse, J. D., additional, Weinheimer, A. J., additional, and Flocke, F., additional

Published
2009
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33. Evolution of Asian aerosols during transpacific transport in INTEX-B

Author

Dunlea, E. J., primary, DeCarlo, P. F., additional, Aiken, A. C., additional, Kimmel, J. R., additional, Peltier, R. E., additional, Weber, R. J., additional, Tomlison, J., additional, Collins, D. R., additional, Shinozuka, Y., additional, McNaughton, C. S., additional, Howell, S. G., additional, Clarke, A. D., additional, Emmons, L. K., additional, Apel, E. C., additional, Pfister, G. G., additional, van Donkelaar, A., additional, Martin, R. V., additional, Millet, D. B., additional, Heald, C. L., additional, and Jimenez, J. L., additional

Published
2008
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34. Supplementary material to "Evolution of Asian aerosols during transpacific transport in INTEX-B"

Author

Dunlea, E. J., primary, DeCarlo, P. F., additional, Aiken, A. C., additional, Kimmel, J. R., additional, Peltier, R. E., additional, Weber, R. J., additional, Tomlison, J., additional, Collins, D. R., additional, Shinozuka, Y., additional, McNaughton, C. S., additional, Howell, S. G., additional, Clarke, A. D., additional, Emmons, L. K., additional, Apel, E. C., additional, Pfister, G. G., additional, van Donkelaar, A., additional, Martin, R. V., additional, Millet, D. B., additional, Heald, C. L., additional, and Jimenez, J. L., additional

Published
2008
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35. Fast airborne aerosol size and chemistry measurements above Mexico City and Central Mexico during the MILAGRO campaign

Author

DeCarlo, P. F., primary, Dunlea, E. J., additional, Kimmel, J. R., additional, Aiken, A. C., additional, Sueper, D., additional, Crounse, J., additional, Wennberg, P. O., additional, Emmons, L., additional, Shinozuka, Y., additional, Clarke, A., additional, Zhou, J., additional, Tomlinson, J., additional, Collins, D. R., additional, Knapp, D., additional, Weinheimer, A. J., additional, Montzka, D. D., additional, Campos, T., additional, and Jimenez, J. L., additional

Published
2008
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36. Analysis of aircraft and satellite measurements from the Intercontinental Chemical Transport Experiment (INTEX-B) to quantify long-range transport of East Asian sulfur to Canada

Author

van Donkelaar, A., primary, Martin, R. V., additional, Leaitch, W. R., additional, Macdonald, A. M., additional, Walker, T. W., additional, Streets, D. G., additional, Zhang, Q., additional, Dunlea, E. J., additional, Jimenez, J. L., additional, Dibb, J. E., additional, Huey, L. G., additional, Weber, R., additional, and Andreae, M. O., additional

Published
2008
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37. Fast airborne aerosol size and chemistry measurements with the high resolution aerosol mass spectrometer during the MILAGRO Campaign

Author

DeCarlo, P. F., primary, Dunlea, E. J., additional, Kimmel, J. R., additional, Aiken, A. C., additional, Sueper, D., additional, Crounse, J., additional, Wennberg, P. O., additional, Emmons, L., additional, Shinozuka, Y., additional, Clarke, A., additional, Zhou, J., additional, Tomlinson, J., additional, Collins, D. R., additional, Knapp, D., additional, Weinheimer, A. J., additional, Montzka, D. D., additional, Campos, T., additional, and Jimenez, J. L., additional

Published
2007
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38. Total Observed Organic Carbon (TOOC): A synthesis of North American observations

Author

Heald, C. L., primary, Goldstein, A. H., additional, Allan, J. D., additional, Aiken, A. C., additional, Apel, E., additional, Atlas, E. L., additional, Baker, A. K., additional, Bates, T. S., additional, Beyersdorf, A. J., additional, Blake, D. R., additional, Campos, T., additional, Coe, H., additional, Crounse, J. D., additional, DeCarlo, P. F., additional, de Gouw, J. A., additional, Dunlea, E. J., additional, Flocke, F. M., additional, Fried, A., additional, Goldan, P., additional, Griffin, R. J., additional, Herndon, S. C., additional, Holloway, J. S., additional, Holzinger, R., additional, Jimenez, J. L., additional, Junkermann, W., additional, Kuster, W. C., additional, Lewis, A. C., additional, Meinardi, S., additional, Millet, D. B., additional, Onasch, T., additional, Polidori, A., additional, Quinn, P. K., additional, Riemer, D. D., additional, Roberts, J. M., additional, Salcedo, D., additional, Sive, B., additional, Swanson, A. L., additional, Talbot, R., additional, Warneke, C., additional, Weber, R. J., additional, Weibring, P., additional, Wennberg, P. O., additional, Wittig, A. E., additional, Zhang, R., additional, Zheng, J., additional, and Zheng, W., additional

Published
2007
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39. Evaluation of nitrogen dioxide chemiluminescence monitors in a polluted urban environment

Author

Dunlea, E. J., primary, Herndon, S. C., additional, Nelson, D. D., additional, Volkamer, R. M., additional, San Martini, F., additional, Sheehy, P. M., additional, Zahniser, M. S., additional, Shorter, J. H., additional, Wormhoudt, J. C., additional, Lamb, B. K., additional, Allwine, E. J., additional, Gaffney, J. S., additional, Marley, N. A., additional, Grutter, M., additional, Marquez, C., additional, Blanco, S., additional, Cardenas, B., additional, Retama, A., additional, Ramos Villegas, C. R., additional, Kolb, C. E., additional, Molina, L. T., additional, and Molina, M. J., additional

Published
2007
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40. Characterization of on-road vehicle emissions in the Mexico City Metropolitan Area using a mobile laboratory in chase and fleet average measurement modes during the MCMA-2003 field campaign

Author

Zavala, M., primary, Herndon, S. C., additional, Slott, R. S., additional, Dunlea, E. J., additional, Marr, L. C., additional, Shorter, J. H., additional, Zahniser, M., additional, Knighton, W. B., additional, Rogers, T. M., additional, Kolb, C. E., additional, Molina, L. T., additional, and Molina, M. J., additional

Published
2006
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41. Implementation of a Markov Chain Monte Carlo method to inorganic aerosol modeling of observations from the MCMA-2003 campaign – Part I: Model description and application to the La Merced site

Author

San Martini, F. M., primary, Dunlea, E. J., additional, Grutter, M., additional, Onasch, T. B., additional, Jayne, J. T., additional, Canagaratna, M. R., additional, Worsnop, D. R., additional, Kolb, C. E., additional, Shorter, J. H., additional, Herndon, S. C., additional, Zahniser, M. S., additional, Ortega, J. M., additional, McRae, G. J., additional, Molina, L. T., additional, and Molina, M. J., additional

Published
2006
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42. Implementation of a Markov Chain Monte Carlo Method to inorganic aerosol modeling of observations from the MCMA-2003 Campaign. Part II: Model application to the CENICA, Pedregal and Santa Ana sites

Author

San Martini, F. M., primary, Dunlea, E. J., additional, Volkamer, R., additional, Onasch, T. B., additional, Jayne, J. T., additional, Canagaratna, M. R., additional, Worsnop, D. R., additional, Kolb, C. E., additional, Shorter, J. H., additional, Herndon, S. C., additional, Zahniser, M. S., additional, Salcedo, D., additional, Dzepina, K., additional, Jimenez, J. L., additional, Ortega, J. M., additional, Johnson, K. S., additional, McRae, G. J., additional, Molina, L. T., additional, and Molina, M. J., additional

Published
2006
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43. Technical note: Evaluation of standard ultraviolet absorption ozone monitors in a polluted urban environment

Author

Dunlea, E. J., primary, Herndon, S. C., additional, Nelson, D. D., additional, Volkamer, R. M., additional, Lamb, B. K., additional, Allwine, E. J., additional, Grutter, M., additional, Ramos Villegas, C. R., additional, Marquez, C., additional, Blanco, S., additional, Cardenas, B., additional, Kolb, C. E., additional, Molina, L. T., additional, and Molina, M. J., additional

Published
2006
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46. Changes in the photochemical environment of the temperate North Pacific troposphere in response to increased Asian emissions

Author

Parrish, D. D., primary, Dunlea, E. J., additional, Atlas, E. L., additional, Schauffler, S., additional, Donnelly, S., additional, Stroud, V., additional, Goldstein, A. H., additional, Millet, D. B., additional, McKay, M., additional, Jaffe, D. A., additional, Price, H. U., additional, Hess, P. G., additional, Flocke, F., additional, and Roberts, J. M., additional

Published
2004
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50. Kinetics of O<INF>2</INF>(<SUP>1</SUP>Σ<INF>g</INF><SUP>+</SUP>) Reaction with H<INF>2</INF> and an Upper Limit for OH Production

Author

Talukdar, R. K., Dunlea, E. J., Brown, S. S., Daniel, J. S., and Ravishankara, A. R.

Abstract

The rate coefficients for the removal of O2(1%@mt;sys@%Σ%@sx@%g%@be@%+%@sxx@%%@mx@% ) (from now on referred to as O2(1Σ)) by H2 were measured between 209 and 373 K by generating O2(1Σ) via pulsed laser excitation near 762 nm. The rate coefficient was determined to be k1 = (6.8 ± 1.2) × 10-12 exp[−(590 ± 52)/T] cm3 molecule-1 s-1. Reaction of O2(1Σ) with O3 yielded O(3P), which was detected by vacuum ultraviolet (VUV)-resonance fluorescence. O2(1Σ) was also prepared by the interaction of O(1D) with O2. In separate experiments, the yield for OH from the title reaction was measured to be &lt;4 × 10-5 at 298 and 209 K. This upper limit was used in a one-dimensional atmospheric model to show that the contribution of this reaction to the total OH production in the atmosphere is minimal under most conditions.

Published
2002
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