294 results on '"Bannan, Thomas J."'
Search Results
2. Study of the Suitability of a Personal Exposure Monitor to Assess Air Quality
- Author
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Aljofi, Halah E., primary, Bannan, Thomas J., additional, Flynn, Michael, additional, Evans, James, additional, Topping, David, additional, Matthews, Emily, additional, Diez, Sebastian, additional, Edwards, Pete, additional, Coe, Hugh, additional, Brison, Daniel R., additional, van Tongeren, Martie, additional, Johnstone, Edward D., additional, and Povey, Andrew, additional
- Published
- 2024
- Full Text
- View/download PDF
3. Tropospheric modeling of acetic acid in the UK for Summer, Winter and Spring seasons using a mesoscale 3-dimensional chemistry and transport model, WRF-Chem-CRI
- Author
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Khan, M. Anwar H., Dennis, James W., Bannan, Thomas J., Bacak, Asan, Booth, Alastair M., Muller, Jennifer B.A., Lowe, Douglas, Percival, Carl J., and Shallcross, Dudley E.
- Published
- 2021
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4. Impact of HO2/RO2 ratio on highly oxygenated α-pinene photooxidation products and secondary organic aerosol formation potential.
- Author
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Baker, Yarê, Kang, Sungah, Wang, Hui, Wu, Rongrong, Xu, Jian, Zanders, Annika, He, Quanfu, Hohaus, Thorsten, Ziehm, Till, Geretti, Veronica, Bannan, Thomas J., O'Meara, Simon P., Voliotis, Aristeidis, Hallquist, Mattias, McFiggans, Gordon, Zorn, Sören R., Wahner, Andreas, and Mentel, Thomas F.
- Subjects
PINENE ,ORGANIC products ,AEROSOLS ,HYDROGEN peroxide ,PEROXY radicals ,PHOTOOXIDATION - Abstract
Highly oxygenated molecules (HOMs) from the atmospheric oxidation of biogenic volatile organic compounds are important contributors to secondary organic aerosol (SOA). Organic peroxy radicals (RO 2) and hydroperoxy radicals (HO 2) are key species influencing the HOM product distribution. In laboratory studies, experimental requirements often result in overemphasis on RO 2 cross-reactions compared to reactions of RO 2 with HO 2. We analyzed the photochemical formation of HOMs from α -pinene and their potential to contribute to SOA formation under high (≈1 /1) and low (≈1 /100) HO2/RO2 conditions. As HO2/RO2 > 1 is prevalent in the daytime atmosphere, sufficiently high HO2/RO2 is crucial to mimic atmospheric conditions and to prevent biases by low HO2/RO2 on the HOM product distribution and thus SOA yield. Experiments were performed under steady-state conditions in the new, continuously stirred tank reactor SAPHIR-STAR at Forschungszentrum Jülich. The HO2/RO2 ratio was increased by adding CO while keeping the OH concentration constant. We determined the HOM's SOA formation potential, considering its fraction remaining in the gas phase after seeding with (NH 4)2 SO 4 aerosol. An increase in HO2/RO2 led to a reduction in SOA formation potential, with the main driver being a ∼ 60 % reduction in HOM-accretion products. We also observed a shift in HOM-monomer functionalization from carbonyl to hydroperoxide groups. We determined a reduction of the HOM's SOA formation potential by ∼ 30 % at HO2/RO2 ≈1 /1 compared to HO2/RO2 ≈ 1/100. Particle-phase observations measured a similar decrease in SOA mass and yield. Our study shows that too low HO2/RO2 ratios compared to the atmosphere can lead to an overestimation of SOA yields. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
5. Data supporting the North Atlantic Climate System: Integrated Studies (ACSIS) programme, including atmospheric composition, oceanographic and sea ice observations (2016-2022) and output from ocean, atmosphere, land and sea-ice models (1950-2050).
- Author
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Archibald, Alex T., Sinha, Bablu, Russo, Maria R., Matthews, Emily, Squires, Freya A., Abraham, N. Luke, Bauguitte, Stephane J.-B., Bannan, Thomas J., Bell, Thomas G., Berry, David, Carpenter, Lucy J., Hugh Coe, Coward, Andrew, Edwards, Peter, Feltham, Daniel, Heard, Dwayne, Hopkins, Jim, Keeble, James, Kent, Elizabeth C., and King, Brian A.
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ATMOSPHERIC composition ,ENVIRONMENTAL research ,ATMOSPHERIC sciences ,GREENLAND ice ,ENTHALPY ,SEA ice ,SEAWATER salinity - Abstract
The North Atlantic Climate System: Integrated Study (ACSIS) was a large multidisciplinary research programme funded by the United Kingdom's Natural Environment Research Council (NERC). ACSIS ran from 2016-22 and brought together around 80 scientists from seven leading UK-based environmental research institutes to deliver major advances in understanding North Atlantic climate variability and extremes. Here we present an overview of the data generated by the ACSIS programme. The datasets cover the full North Atlantic System comprising: the North Atlantic Ocean, the atmosphere above it including its composition, Arctic Sea Ice and the Greenland Ice Sheet. Atmospheric composition datasets include measurements from 7 aircraft campaigns (between 3 and 10 flights each, 0-10 km altitude range) in the north eastern Atlantic (~40° W-5° E,~15° N-55° N) made at intervals of from 6 months to 2 years between February 2017 and may 2022. The flights measured chemical species (including greenhouse gases, ozone precursors and VOCs) and aerosols (organic, SO
4 , NH4 , NO3 , and nss-Cl) (https://dx.doi.org/10.5285/6285564c34a246fc9ba5ce053d85e5e7 (FAAM et al. (2024)). Ground based stations at the Cape Verde Atmospheric Observatory (CVAO), Penlee Point Atmospheric Observatory (PPAO) and Plymouth Marine Laboratory (PML) recorded ozone, ozone precursors, halocarbons, as well as greenhouse gases (CO2 , methane), SO2 and photolysis rates. (CVAO, http://catalogue.ceda.ac.uk/uuid/81693aad69409100b1b9a247b9ae75d5, National Centre for Atmospheric Science et al. (2014)), O3 and CH4 (PPAO, https://catalogue.ceda.ac.uk/uuid/8f1ff8ea77534e08b03983685990a9b0 (Plymouth Marine Laboratory and Yang (2024)) and aerosols (PML, https://dx.doi.org/10.5285/e74491c96ef24df29a9342a3d57b5939, Smyth (2024)). Complementary model simulations of atmospheric composition were performed with the UK Earth System Model, UKESM1, for the period 1982 to 2020 using CMIP6 historical forcing up to 2014 and SSP3-7.0 scenario from 2015-2020. Model temperature and winds were relaxed towards ERA reanalysis. Monthly mean model data for ozone, NO, NO2 , CO, methane, stratospheric ozone tracers and 30 regionally emitted tracers are available to download (https://data.ceda.ac.uk/badc/acsis/UKESM1-hindcasts, Abraham (2024)). ACSIS also generated new ocean heat content diagnostics https://doi.org/10/g6wm, https://doi.org/10/g8g2, Moat et al. (2021a-b) and gridded temperature and salinity based on objectively mapped Argo measurements https://doi.org/10.5285/fe8e524d-7f04-41f3-e053-6c86abc04d51 (King (2023). An ensemble of atmosphere-forced global ocean-sea ice simulations using the NEMO-CICE model was performed with horizontal resolutions of 1/4° and 1/12° covering the period 1958-2020 using several different atmosphere reanalysis based surface forcing datasets, supplemented by additional global simulations and standalone sea ice model simulations with advanced sea ice physics using the CICE model (http://catalogue.ceda.ac.uk/uuid/770a885a8bc34d51ad71e87ef346d6a8, Megann et al. (2021e). Output is stored as monthly averages and includes 3D potential temperature, salinity, zonal, meridional and vertical velocity; 2D sea surface height, mixed layer depth, surface heat and freshwater fluxes, ice concentration and thickness and a wide variety of other variables. In addition to the data presented here we provide a brief overview of several other datasets that were generated during ACSIS which have been described previously in the literature. [ABSTRACT FROM AUTHOR]- Published
- 2024
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6. Assessing the Accuracy of Air Quality Personal Exposure Monitors
- Author
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Aljofi, Halah E., primary, Bannan, Thomas J., additional, Flynn, Michael, additional, Evans, James Z, additional, Topping, David O., additional, Matthews, Emily, additional, Diez, Sebastian, additional, Edwards, Pete M, additional, Coe, Hugh, additional, Brison, Daniel R., additional, Van Tongeren, Martie, additional, Johnstone, Edward D., additional, and Povey, Andrew C., additional
- Published
- 2023
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- View/download PDF
7. Secondary organic aerosol reduced by mixture of atmospheric vapours
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McFiggans, Gordon, Mentel, Thomas F., Wildt, Jürgen, Pullinen, Iida, Kang, Sungah, Kleist, Einhard, Schmitt, Sebastian, Springer, Monika, Tillmann, Ralf, Wu, Cheng, Zhao, Defeng, Hallquist, Mattias, Faxon, Cameron, Le Breton, Michael, Hallquist, Åsa M., Simpson, David, Bergström, Robert, Jenkin, Michael E., Ehn, Mikael, Thornton, Joel A., Alfarra, M. Rami, Bannan, Thomas J., Percival, Carl J., Priestley, Michael, Topping, David, and Kiendler-Scharr, Astrid
- Published
- 2019
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8. Airborne observations over the North Atlantic Ocean reveal the importance of gas-phase urea in the atmosphere
- Author
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Matthews, Emily, primary, Bannan, Thomas J., additional, Khan, M. Anwar H., additional, Shallcross, Dudley E., additional, Stark, Harald, additional, Browne, Eleanor C., additional, Archibald, Alexander T., additional, Mehra, Archit, additional, Bauguitte, Stéphane J.-B., additional, Reed, Chris, additional, Thamban, Navaneeth M., additional, Wu, Huihui, additional, Barker, Patrick, additional, Lee, James, additional, Carpenter, Lucy J., additional, Yang, Mingxi, additional, Bell, Thomas G., additional, Allen, Grant, additional, Jayne, John T., additional, Percival, Carl J., additional, McFiggans, Gordon, additional, Gallagher, Martin, additional, and Coe, Hugh, additional
- Published
- 2023
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9. Impact of HO2 aerosol uptake on radical levels and O3 production during summertime in Beijing
- Author
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Dyson, Joanna E., primary, Whalley, Lisa K., additional, Slater, Eloise J., additional, Woodward-Massey, Robert, additional, Ye, Chunxiang, additional, Lee, James D., additional, Squires, Freya, additional, Hopkins, James R., additional, Dunmore, Rachel E., additional, Shaw, Marvin, additional, Hamilton, Jacqueline F., additional, Lewis, Alastair C., additional, Worrall, Stephen D., additional, Bacak, Asan, additional, Mehra, Archit, additional, Bannan, Thomas J., additional, Coe, Hugh, additional, Percival, Carl J., additional, Ouyang, Bin, additional, Hewitt, C. Nicholas, additional, Jones, Roderic L., additional, Crilley, Leigh R., additional, Kramer, Louisa J., additional, Acton, W. Joe F., additional, Bloss, William J., additional, Saksakulkrai, Supattarachai, additional, Xu, Jingsha, additional, Shi, Zongbo, additional, Harrison, Roy M., additional, Kotthaus, Simone, additional, Grimmond, Sue, additional, Sun, Yele, additional, Xu, Weiqi, additional, Yue, Siyao, additional, Wei, Lianfang, additional, Fu, Pingqing, additional, Wang, Xinming, additional, Arnold, Stephen R., additional, and Heard, Dwayne E., additional
- Published
- 2023
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10. Enhanced ozone loss by active inorganic bromine chemistry in the tropical troposphere
- Author
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Le Breton, Michael, Bannan, Thomas J., Shallcross, Dudley E., Khan, M. Anwar, Evans, Mathew J., Lee, James, Lidster, Richard, Andrews, Stephen, Carpenter, Lucy J., Schmidt, Johan, Jacob, Daniel, Harris, Neil R.P., Bauguitte, Stephane, Gallagher, Martin, Bacak, Asan, Leather, Kimberley E., and Percival, Carl J.
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- 2017
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11. Low-cost air quality sensors: The good, the bad, and the ugly. Preliminary findings from the QUANT study
- Author
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Lacy, Stuart E, primary, Diez, Sebastian, additional, Bannan, Thomas J, additional, Flynn, Michael, additional, Watson, Nathan, additional, Marsden, Nicholas, additional, Priestman, Max, additional, and Edwards, Pete M, additional
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- 2023
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12. Impact of HO2/RO2 ratio on highly oxygenated α-pinene photooxidation products and secondary organic aerosol formation potential.
- Author
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Baker, Yarê, Kang, Sungah, Wang, Hui, Wu, Rongrong, Xu, Jian, Zanders, Annika, He, Quanfu, Hohaus, Thorsten, Ziehm, Till, Geretti, Veronica, Bannan, Thomas J., O'Meara, Simon P., Voliotis, Aristeidis, Hallquist, Mattias, McFiggans, Gordon, Zorn, Sören R., Wahner, Andreas, and Mentel, Thomas
- Subjects
PINENE ,ORGANIC products ,AEROSOLS ,HYDROGEN peroxide ,PEROXY radicals ,PHOTOOXIDATION - Abstract
Highly oxygenated molecules (HOM) from the atmospheric oxidation of biogenic volatile organic compounds are important contributors to secondary organic aerosol (SOA). Organic peroxy radicals (RO
2 ) and hydroperoxy radicals (HO2 ) are key species influencing the HOM product distribution. In laboratory studies experimental requirements often result in overemphasis of RO2 cross-reactions compared to reactions of RO2 with HO2 . We analyzed the photochemical formation of HOMs from α-pinene and their potential to contribute to SOA formation under high (≈1/1) and low (≈1/100) HO2 /RO2 conditions. As HO2 /RO2 > 1 is prevalent in the daytime atmosphere, sufficiently high HO2 /RO2 is crucial to mimic atmospheric conditions and to prevent biases by low HO2 /RO2 on the HOM product distribution and thus SOA yield. Experiments were performed under steady-state conditions in the new, continuously stirred tank reactor SAPHIR-STAR at Forschungszentrum Jülich. The HO2 /RO2 ratio was increased by adding CO, while keeping the OH concentration constant. We determined the HOM's SOA formation potential, considering their fraction remaining in the gas phase after seeding with (NH4 )2 SO4 aerosol. Increase of HO2 /RO2 led to a reduction in SOA formation potential, with the main driver being a ≈60 % reduction in HOM-accretion products. We also observed a shift in HOM-monomer functionalization from carbonyl to hydroperoxide groups. We determined a reduction of the HOM's SOA formation potential by ≈30 % at HO2 /RO2 ≈1/1. Particle phase observations measured an about according decrease in SOA mass and yield. Our study showed that too low HO2 /RO2 ratios compared to the atmosphere can lead to an overestimation of SOA yields. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
13. Supplementary material to "Impact of HO2 aerosol uptake on radical levels and O3 production during summertime in Beijing"
- Author
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Dyson, Joanna E., primary, Whalley, Lisa K., additional, Slater, Eloise J., additional, Woodward-Massey, Robert, additional, Ye, Chunxiang, additional, Lee, James D., additional, Squires, Freya, additional, Hopkins, James R., additional, Dunmore, Rachel E., additional, Shaw, Marvin, additional, Hamilton, Jacqueline F., additional, Lewis, Alastair C., additional, Worrall, Stephen D., additional, Bacak, Asan, additional, Mehra, Archit, additional, Bannan, Thomas J., additional, Coe, Hugh, additional, Percival, Carl J., additional, Ouyang, Bin, additional, Hewitt, C. Nicholas, additional, Jones, Roderic L., additional, Crilley, Leigh R., additional, Kramer, Louisa J., additional, Acton, W. Joe F., additional, Bloss, William J., additional, Saksakulkrai, Supattarachai, additional, Xu, Jingsha, additional, Shi, Zongbo, additional, Harrison, Roy M., additional, Kotthaus, Simone, additional, Grimmond, Sue, additional, Sun, Yele, additional, Xu, Weiqi, additional, Yue, Siyao, additional, Wei, Lianfang, additional, Fu, Pingqing, additional, Wang, Xinming, additional, Arnold, Stephen R., additional, and Heard, Dwayne E., additional
- Published
- 2022
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- View/download PDF
14. Impact of HO2 aerosol uptake on radical levels and O3 production during summertime in Beijing
- Author
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Dyson, Joanna E., primary, Whalley, Lisa K., additional, Slater, Eloise J., additional, Woodward-Massey, Robert, additional, Ye, Chunxiang, additional, Lee, James D., additional, Squires, Freya, additional, Hopkins, James R., additional, Dunmore, Rachel E., additional, Shaw, Marvin, additional, Hamilton, Jacqueline F., additional, Lewis, Alastair C., additional, Worrall, Stephen D., additional, Bacak, Asan, additional, Mehra, Archit, additional, Bannan, Thomas J., additional, Coe, Hugh, additional, Percival, Carl J., additional, Ouyang, Bin, additional, Hewitt, C. Nicholas, additional, Jones, Roderic L., additional, Crilley, Leigh R., additional, Kramer, Louisa J., additional, Acton, W. Joe F., additional, Bloss, William J., additional, Saksakulkrai, Supattarachai, additional, Xu, Jingsha, additional, Shi, Zongbo, additional, Harrison, Roy M., additional, Kotthaus, Simone, additional, Grimmond, Sue, additional, Sun, Yele, additional, Xu, Weiqi, additional, Yue, Siyao, additional, Wei, Lianfang, additional, Fu, Pingqing, additional, Wang, Xinming, additional, Arnold, Stephen R., additional, and Heard, Dwayne E., additional
- Published
- 2022
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15. Evaluation of isoprene nitrate chemistry in detailed chemical mechanisms
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Mayhew, Alfred W., primary, Lee, Ben H., additional, Thornton, Joel A., additional, Bannan, Thomas J., additional, Brean, James, additional, Hopkins, James R., additional, Lee, James D., additional, Nelson, Beth S., additional, Percival, Carl, additional, Rickard, Andrew R., additional, Shaw, Marvin D., additional, Edwards, Peter M., additional, and Hamilton, Jaqueline F., additional
- Published
- 2022
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16. Chamber investigation of the formation and transformation of secondary organic aerosol in mixtures of biogenic and anthropogenic volatile organic compounds
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Voliotis, Aristeidis, primary, Du, Mao, additional, Wang, Yu, additional, Shao, Yunqi, additional, Alfarra, M. Rami, additional, Bannan, Thomas J., additional, Hu, Dawei, additional, Pereira, Kelly L., additional, Hamilton, Jaqueline F., additional, Hallquist, Mattias, additional, Mentel, Thomas F., additional, and McFiggans, Gordon, additional
- Published
- 2022
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17. Airborne measurements of HC(O)OH in the European Arctic: A winter – summer comparison
- Author
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Jones, Benjamin T., Muller, Jennifer B.A., O'Shea, Sebastian J., Bacak, Asan, Le Breton, Michael, Bannan, Thomas J., Leather, Kimberley E., Booth, A. Murray, Illingworth, Sam, Bower, Keith, Gallagher, Martin W., Allen, Grant, Shallcross, Dudley E., Bauguitte, Stephane J.-B., Pyle, John A., and Percival, Carl J.
- Published
- 2014
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18. Importance of direct anthropogenic emissions of formic acid measured by a chemical ionisation mass spectrometer (CIMS) during the Winter ClearfLo Campaign in London, January 2012
- Author
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Bannan, Thomas J., Bacak, Asan, Muller, Jennifer B.A., Booth, A. Murray, Jones, Benjamin, Le Breton, Michael, Leather, Kimberley E., Ghalaieny, Mohamed, Xiao, Ping, Shallcross, Dudley E., and Percival, Carl J.
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- 2014
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19. Combined application of online FIGAERO-CIMS and offline LC-Orbitrap mass spectrometry (MS) to characterize the chemical composition of secondary organic aerosol (SOA) in smog chamber studies
- Author
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Du, Mao, primary, Voliotis, Aristeidis, additional, Shao, Yunqi, additional, Wang, Yu, additional, Bannan, Thomas J., additional, Pereira, Kelly L., additional, Hamilton, Jacqueline F., additional, Percival, Carl J., additional, Alfarra, M. Rami, additional, and McFiggans, Gordon, additional
- Published
- 2022
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20. Air pollution measurement errors: is your data fit for purpose?
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Diez, Sebastian, primary, Lacy, Stuart E., additional, Bannan, Thomas J., additional, Flynn, Michael, additional, Gardiner, Tom, additional, Harrison, David, additional, Marsden, Nicholas, additional, Martin, Nicholas A., additional, Read, Katie, additional, and Edwards, Pete M., additional
- Published
- 2022
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21. The influence of the addition of a reactive low SOA yield VOC on the volatility of particles formed from photo-oxidation of anthropogenic – biogenic mixtures
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Voliotis, Aristeidis, primary, Du, Mao, additional, Wang, Yu, additional, Shao, Yunqi, additional, Bannan, Thomas J., additional, Flynn, Michael, additional, Pandis, Spyros N., additional, Percival, Carl J., additional, Alfarra, M. Rami, additional, and McFiggans, Gordon, additional
- Published
- 2022
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22. Supplementary material to "The influence of the addition of a reactive low SOA yield VOC on the volatility of particles formed from photo-oxidation of anthropogenic – biogenic mixtures"
- Author
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Voliotis, Aristeidis, primary, Du, Mao, additional, Wang, Yu, additional, Shao, Yunqi, additional, Bannan, Thomas J., additional, Flynn, Michael, additional, Pandis, Spyros N., additional, Percival, Carl J., additional, Alfarra, M. Rami, additional, and McFiggans, Gordon, additional
- Published
- 2022
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23. A Four Carbon Organonitrate as a Significant Product of Secondary Isoprene Chemistry
- Author
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Tsiligiannis, Epameinondas, primary, Wu, Rongrong, additional, Lee, Ben H., additional, Salvador, Christian Mark, additional, Priestley, Michael, additional, Carlsson, Philip T. M., additional, Kang, Sungah, additional, Novelli, Anna, additional, Vereecken, Luc, additional, Fuchs, Hendrik, additional, Mayhew, Alfred W., additional, Hamilton, Jacqueline F., additional, Edwards, Peter M., additional, Fry, Juliane L., additional, Brownwood, Bellamy, additional, Brown, Steven S., additional, Wild, Robert J., additional, Bannan, Thomas J., additional, Coe, Hugh, additional, Allan, James, additional, Surratt, Jason D., additional, Bacak, Asan, additional, Artaxo, Paul, additional, Percival, Carl, additional, Guo, Song, additional, Hu, Min, additional, Wang, Tao, additional, Mentel, Thomas F., additional, Thornton, Joel A., additional, and Hallquist, Mattias, additional
- Published
- 2022
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- View/download PDF
24. Supplementary material to "Evaluation of Isoprene Nitrate Chemistry in Detailed Chemical Mechanisms"
- Author
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Mayhew, Alfred W., primary, Lee, Ben H., additional, Thornton, Joel A., additional, Bannan, Thomas J., additional, Brean, James, additional, Hopkins, James R., additional, Lee, James D., additional, Nelson, Beth S., additional, Percival, Carl, additional, Rickard, Andrew R., additional, Shaw, Marvin D., additional, Edwards, Peter M., additional, and Hamilton, Jaqueline F., additional
- Published
- 2022
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25. Protecting playgrounds:local-scale reduction of airborne particulate matter concentrations through particulate deposition on roadside ‘tredges’ (green infrastructure)
- Author
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Maher, Barbara A., Gonet, Tomasz, Karloukovski, Vassil V., Wang, Huixia, Bannan, Thomas J., Maher, Barbara A., Gonet, Tomasz, Karloukovski, Vassil V., Wang, Huixia, and Bannan, Thomas J.
- Abstract
Exposure to traffic-related particulate air pollution has been linked with excess risks for a range of cardiovascular, respiratory and neurological health outcomes; risks likely to be exacerbated in young children attending schools adjacent to highly-trafficked roads. One immediate way of reducing airborne PM concentrations at the local (i.e., near-road community) scale is installation of roadside vegetation as a means of passive pollution abatement. Roadside vegetation can decrease airborne PM concentrations, through PM deposition on leaves, but can also increase them, by impeding airflow and PM dispersion. Critical to optimizing PM removal is selection of species with high particle deposition velocity (Vd) values, currently under-parameterised in most modelling studies. Here, the measured amounts of leaf-deposited magnetic PM after roadside greening (‘tredge’) installation, and measured reductions in playground PM, particle number and black carbon concentrations demonstrate that air quality improvements by deposition can be achieved at the local, near-road, community/playground scale. PM deposition on the western red cedar tredge removed ~ 49% of BC, and ~ 46% and 26% of the traffic-sourced PM2.5 and PM1, respectively. These findings demonstrate that roadside vegetation can be designed, installed and maintained to achieve rapid, significant, cost-effective improvement of air quality by optimising PM deposition on plant leaves.
- Published
- 2022
26. A Four Carbon Organonitrate as a Significant Product of Secondary Isoprene Chemistry
- Author
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Tsiligiannis, Epameinondas, Wu, Rongrong, Lee, Ben H., Salvador, Christian Mark, Priestley, Michael, Carlsson, Philip T.M., Kang, Sungah, Novelli, Anna, Vereecken, Luc, Fuchs, Hendrik, Mayhew, Alfred W., Hamilton, Jacqueline F., Edwards, Peter M., Fry, Juliane L., Brownwood, Bellamy, Brown, Steven S., Wild, Robert J., Bannan, Thomas J., Coe, Hugh, Allan, James, Surratt, Jason D., Bacak, Asan, Artaxo, Paul, Percival, Carl, Guo, Song, Hu, Min, Wang, Tao, Mentel, Thomas F., Thornton, Joel A., Hallquist, Mattias, Tsiligiannis, Epameinondas, Wu, Rongrong, Lee, Ben H., Salvador, Christian Mark, Priestley, Michael, Carlsson, Philip T.M., Kang, Sungah, Novelli, Anna, Vereecken, Luc, Fuchs, Hendrik, Mayhew, Alfred W., Hamilton, Jacqueline F., Edwards, Peter M., Fry, Juliane L., Brownwood, Bellamy, Brown, Steven S., Wild, Robert J., Bannan, Thomas J., Coe, Hugh, Allan, James, Surratt, Jason D., Bacak, Asan, Artaxo, Paul, Percival, Carl, Guo, Song, Hu, Min, Wang, Tao, Mentel, Thomas F., Thornton, Joel A., and Hallquist, Mattias
- Abstract
Oxidation of isoprene by nitrate radicals (NO3) or by hydroxyl radicals (OH) under high NOx conditions forms a substantial amount of organonitrates (ONs). ONs impact NOx concentrations and consequently ozone formation while also contributing to secondary organic aerosol. Here we show that the ONs with the chemical formula C4H7NO5 are a significant fraction of isoprene-derived ONs, based on chamber experiments and ambient measurements from different sites around the globe. From chamber experiments we found that C4H7NO5 isomers contribute 5%–17% of all measured ONs formed during nighttime and constitute more than 40% of the measured ONs after further daytime oxidation. In ambient measurements C4H7NO5 isomers usually dominate both nighttime and daytime, implying a long residence time compared to C5 ONs which are removed more rapidly. We propose potential nighttime sources and secondary formation pathways, and test them using a box model with an updated isoprene oxidation scheme.
- Published
- 2022
27. Isotopic signatures of methane emissions from tropical fires, agriculture and wetlands: the MOYA and ZWAMPS flights
- Author
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MOYA/ZWAMPS Team, Nisbet, Euan G, Allen, Grant, Fisher, Rebecca E, France, James L, Lee, James D, Lowry, David, Andrade, Marcos F, Bannan, Thomas J, Barker, Patrick, Bateson, Prudence, Bauguitte, Stéphane J-B, Bower, Keith N, Broderick, Tim J, Chibesakunda, Francis, Cain, Michelle, Cozens, Alice E, Daly, Michael C, Ganesan, Anita L, Jones, Anna E, Lambakasa, Musa, Lunt, Mark F, Mehra, Archit, Moreno, Isabel, Pasternak, Dominika, Palmer, Paul I, Percival, Carl J, Pitt, Joseph R, Riddle, Amber J, Rigby, Matthew, Shaw, Jacob T, Stell, Angharad C, Vaughan, Adam R, Warwick, Nicola J, E Wilde, Shona, Nisbet, Euan G [0000-0001-8379-857X], Allen, Grant [0000-0002-7070-3620], France, James L [0000-0002-8785-1240], Barker, Patrick [0000-0001-8754-4278], Cain, Michelle [0000-0003-2062-6556], Daly, Michael C [0000-0002-3426-0164], Palmer, Paul I [0000-0002-1487-0969], Pitt, Joseph R [0000-0002-8660-5136], Stell, Angharad C [0000-0003-0349-2859], and Apollo - University of Cambridge Repository
- Subjects
African wetlands ,General Mathematics ,General Engineering ,African biomass burning ,General Physics and Astronomy ,Agriculture ,Articles ,African air pollution ,atmospheric methane ,aircraft surveys ,Air Pollution ,Wetlands ,Animals ,Cattle ,methane isotopes ,Seasons ,Methane ,Research Articles - Abstract
We report methane isotopologue data from aircraft and ground measurements in Africa and South America. Aircraft campaigns sampled strong methane fluxes over tropical papyrus wetlands in the Nile, Congo and Zambezi basins, herbaceous wetlands in Bolivian southern Amazonia, and over fires in African woodland, cropland and savannah grassland. Measured methaneδ13CCH4isotopic signatures were in the range −55 to −49‰ for emissions from equatorial Nile wetlands and agricultural areas, but widely −60 ± 1‰ from Upper Congo and Zambezi wetlands. Very similarδ13CCH4signatures were measured over the Amazonian wetlands of NE Bolivia (around −59‰) and the overallδ13CCH4signature from outer tropical wetlands in the southern Upper Congo and Upper Amazon drainage plotted together was −59 ± 2‰. These results were more negative than expected. For African cattle,δ13CCH4values were around −60 to −50‰. Isotopic ratios in methane emitted by tropical fires depended on the C3 : C4 ratio of the biomass fuel. In smoke from tropical C3 dry forest fires in Senegal,δ13CCH4values were around −28‰. By contrast, African C4 tropical grass fireδ13CCH4values were −16 to −12‰. Methane from urban landfills in Zambia and Zimbabwe, which have frequent waste fires, hadδ13CCH4around −37 to −36‰. These new isotopic values help improve isotopic constraints on global methane budget models because atmosphericδ13CCH4values predicted by global atmospheric models are highly sensitive to theδ13CCH4isotopic signatures applied to tropical wetland emissions. Field and aircraft campaigns also observed widespread regional smoke pollution over Africa, in both the wet and dry seasons, and large urban pollution plumes. The work highlights the need to understand tropical greenhouse gas emissions in order to meet the goals of the UNFCCC Paris Agreement, and to help reduce air pollution over wide regions of Africa.This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part 2)'.
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- 2022
28. Monitoring and Understanding Urban Transformation: A Mixed Method Approach
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Bannan, Thomas J., primary, Evans, James, additional, Benton, Jack S., additional, Edwards, Pete, additional, Diez, Sebastian, additional, Marsden, Nicholas, additional, Flynn, Michael, additional, Coe, Hugh, additional, Burke, Clare, additional, Murabito, Ettore, additional, Anderson, Jamie, additional, Cruickshank, Sheena M., additional, and Topping, David, additional
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- 2022
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29. Supplementary material to "Chamber investigation of the formation and transformation of secondary organic aerosol in mixtures of biogenic and anthropogenic volatile organic compounds"
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Voliotis, Aristeidis, primary, Du, Mao, additional, Wang, Yu, additional, Shao, Yunqi, additional, Alfarra, M. Rami, additional, Bannan, Thomas J., additional, Hu, Dawei, additional, Pereira, Kelly L., additional, Hamilton, Jaqueline F., additional, Hallquist, Mattias, additional, Mentel, Thomas F., additional, and McFiggans, Gordon, additional
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- 2022
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30. Supplementary material to "Combined application of Online FIGAERO-CIMS and Offline LC-Orbitrap MS to Characterize the Chemical Composition of SOA in Smog Chamber Studies"
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Du, Mao, primary, Voliotis, Aristeidis, additional, Shao, Yunqi, additional, Wang, Yu, additional, Bannan, Thomas J., additional, Pereira, Kelly L., additional, Hamilton, Jacqueline F., additional, Percival, Carl J., additional, Alfarra, M. Rami, additional, and McFiggans, Gordon, additional
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- 2021
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31. Digital Twins of Urban Air Quality: Opportunities and Challenges
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Topping, David, primary, Bannan, Thomas J., additional, Coe, Hugh, additional, Evans, James, additional, Jay, Caroline, additional, Murabito, Ettore, additional, and Robinson, Niall, additional
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- 2021
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32. Impact of HO2 aerosol uptake on radical levels and O3 production during summertime in Beijing.
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Dyson, Joanna E., Whalley, Lisa K., Slater, Eloise J., Woodward-Massey, Robert, Chunxiang Ye, Lee, James D., Squires, Freya, Hopkins, James R., Dunmore, Rachel E., Shaw, Marvin, Hamilton, Jacqueline F., Lewis, Alastair C., Worrall, Stephen D., Bacak, Asan, Mehra, Archit, Bannan, Thomas J., Coe, Hugh, Percival, Carl J., Bin Ouyang, and Hewitt, C. Nicholas
- Abstract
The impact of heterogeneous uptake of HO
2 onto aerosol surfaces on radical concentrations and the O3 production regime in Beijing summertime was investigated. The uptake coefficient of HO2 onto aerosol surfaces, γHO2 , was calculated for the AIRPRO campaign in Beijing, Summer 2017, as a function of measured aerosol soluble copper concentration, [Cu2+ ]eff, aerosol liquid water content, [ALWC], and particulate matter concentration, [PM]. An average γHO2 across the entire campaign of 0.070 ± 0.035 was calculated, with values ranging from 0.002 to 0.15, and found to be significantly lower than the value of γHO2 =0.2, commonly used in modelling studies. Using the calculated γHO2 values for the Summer AIRPRO campaign, OH, HO2 and RO2 radical concentrations were modelled using a box-model incorporating the Master Chemical Mechanism (v3.3.1), with and without the addition of γHO2 , and compared to the measured radical concentrations. Rate of destruction analysis showed the dominant HO2 loss pathway to be HO2 + NO for all NO concentrations across the Summer Beijing campaign with HO2 uptake contributing < 0.3 % to the total loss of HO2 on average. This result for Beijing summertime would suggest that under most conditions encountered, HO2 uptake onto aerosol surfaces is not important to consider when investigating increasing O3 production with decreasing [PM] across the North China Plain. At low [NO], however, i.e. < 0.1 ppb, which was often encountered in the afternoons, up to 29% of modelled HO2 loss was due to HO2 uptake on aerosols when calculated γHO2 was included, even with the much lower γHO2 values compared to γHO2 =0.2, a results which agrees with the aerosol-inhibited O3 regime recently proposed by Ivatt et al., 2022. As such it can be concluded that in cleaner environments, away from polluted urban centres where HO2 loss chemistry is not dominated by NO but where aerosol surface area is high still, changes in PM concentration and hence aerosol surface area could still have a significant effect on both overall HO2 concentration and the O3 production regime. Using modelled radical concentrations, the absolute O3 sensitivity to NOx and VOC showed that, on average across the summer AIRPRO campaign, the O3 production regime remained VOC-limited, with the exception of a few days in the afternoon when the NO mixing ratio dropped low enough for the O3 regime to shift towards NOx -limited. The O3 sensitivity to VOC, the dominant regime during the summer AIRPRO campaign, was observed to decrease and shift towards a NOx sensitive regime both when NO mixing ratio decreased and with the addition of aerosol uptake. This suggests that if [NOx ] continues to decrease in the future, ozone reduction policies focussing solely on NOx reductions may not be as efficient as expected if [PM] and, hence, HO2 uptake to aerosol surfaces, continues to decrease. The addition of aerosol uptake into the model, for both the γHO2 calculated from measured data and when using a fixed value of γHO2 =0.2, did not have a significant effect on the overall O3 production regime across the campaign. While not important for this campaign, aerosol uptake could be important for areas of lower NO concentration that are already in a NOx -sensitive regime. [ABSTRACT FROM AUTHOR]- Published
- 2022
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33. Abundance of NO3 Derived Organo-Nitrates and Their Importance in the Atmosphere
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Foulds, Amy, primary, Khan, M. Anwar H., additional, Bannan, Thomas J., additional, Percival, Carl J., additional, Lowenberg, Mark H., additional, and Shallcross, Dudley E., additional
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- 2021
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34. Exploring the composition and volatility of secondary organic aerosols in mixed anthropogenic and biogenic precursor systems
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Voliotis, Aristeidis, primary, Wang, Yu, additional, Shao, Yunqi, additional, Du, Mao, additional, Bannan, Thomas J., additional, Percival, Carl J., additional, Pandis, Spyros N., additional, Alfarra, M. Rami, additional, and McFiggans, Gordon, additional
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- 2021
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35. Global tropospheric halogen (Cl, Br, I) chemistry and its impact on oxidants
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Wang, Xuan, primary, Jacob, Daniel J., additional, Downs, William, additional, Zhai, Shuting, additional, Zhu, Lei, additional, Shah, Viral, additional, Holmes, Christopher D., additional, Sherwen, Tomás, additional, Alexander, Becky, additional, Evans, Mathew J., additional, Eastham, Sebastian D., additional, Neuman, J. Andrew, additional, Veres, Patrick R., additional, Koenig, Theodore K., additional, Volkamer, Rainer, additional, Huey, L. Gregory, additional, Bannan, Thomas J., additional, Percival, Carl J., additional, Lee, Ben H., additional, and Thornton, Joel A., additional
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- 2021
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36. Impacts of Hydroperoxymethyl Thioformate on the Global Marine Sulfur Budget
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Khan, M. Anwar H., primary, Bannan, Thomas J., additional, Holland, Rayne, additional, Shallcross, Dudley E., additional, Archibald, Alex T., additional, Matthews, Emily, additional, Back, Asan, additional, Allan, James, additional, Coe, Hugh, additional, Artaxo, Paulo, additional, and Percival, Carl J., additional
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- 2021
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37. Improvements to the representation of BVOC chemistry–climate interactions in UKCA (v11.5) with the CRI-Strat 2 mechanism: incorporation and evaluation
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Weber, James, primary, Archer-Nicholls, Scott, additional, Abraham, Nathan Luke, additional, Shin, Youngsub M., additional, Bannan, Thomas J., additional, Percival, Carl J., additional, Bacak, Asan, additional, Artaxo, Paulo, additional, Jenkin, Michael, additional, Khan, M. Anwar H., additional, Shallcross, Dudley E., additional, Schwantes, Rebecca H., additional, Williams, Jonathan, additional, and Archibald, Alex T., additional
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- 2021
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38. Chemical characterisation of benzene oxidation products under high- And low-NOx conditions using chemical ionisation mass spectrometry
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Priestley, Michael, Bannan, Thomas J., Breton, Michael, Worrall, Stephen D., Kang, Sungah, Pullinen, Iida, Schmitt, Sebastian, Tillmann, Ralf, Kleist, Einhard, Zhao, Defeng, Wildt, Jürgen, Garmash, Olga, Mehra, Archit, Bacak, Asan, Shallcross, Dudley E., Kiendler-Scharr, Astrid, Hallquist, Åsa M., Ehn, Mikael, Coe, Hugh, Percival, Carl J., Hallquist, Mattias, Mentel, Thomas F., McFiggans, Gordon, INAR Physics, and Institute for Atmospheric and Earth System Research (INAR)
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ddc:550 ,114 Physical sciences - Abstract
Aromatic hydrocarbons are a class of volatile organic compounds associated with anthropogenic activity and make up a significant fraction of urban volatile organic compound (VOC) emissions that contribute to the formation of secondary organic aerosol (SOA). Benzene is one of the most abundant species emitted from vehicles, biomass burning and industry. An iodide time-of-flight chemical ionisation mass spectrometer (ToF-CIMS) and nitrate ToF-CIMS were deployed at the Jülich Plant Atmosphere Chamber as part of a series of experiments examining benzene oxidation by OH under high- and low-NOx conditions, where a range of organic oxidation products were detected. The nitrate scheme detects many oxidation products with high masses, ranging from intermediate volatile organic compounds (IVOCs) to extremely low volatile organic compounds (ELVOCs), including C12 dimers. In comparison, very few species with C≥6 and O≥8 were detected with the iodide scheme, which detected many more IVOCs and semi-volatile organic compounds (SVOCs) but very few ELVOCs and low volatile organic compounds (LVOCs). A total of 132 and 195 CHO and CHON oxidation products are detected by the iodide ToF-CIMS in the low- and high-NOx experiments respectively. Ring-breaking products make up the dominant fraction of detected signal and 21 and 26 of the products listed in the Master Chemical Mechanism (MCM) were detected. The time series of highly oxidised (O≥6) and ring-retaining oxidation products (C6 and double-bond equivalent = 4) equilibrate quickly, characterised by a square form profile, compared to MCM and ring-breaking products which increase throughout oxidation, exhibiting sawtooth profiles. Under low-NOx conditions, all CHO formulae attributed to radical termination reactions of first-generation benzene products, and first-generation auto-oxidation products are observed. Several N-containing species that are either first-generation benzene products or first-generation auto-oxidation products are also observed under high-NOx conditions. Hierarchical cluster analysis finds four clusters, of which two describe photo-oxidation. Cluster 2 shows a negative dependency on the NO2/NOx ratio, indicating it is sensitive to NO concentration and thus likely to contain NO addition products and alkoxy-derived termination products. This cluster has the highest average carbon oxidation state (OSC‾) and the lowest average carbon number. Where nitrogen is present in a cluster member of cluster 2, the oxygen number is even, as expected for alkoxy-derived products. In contrast, cluster 1 shows no dependency on the NO2/NOx ratio and so is likely to contain more NO2 addition and peroxy-derived termination products. This cluster contains fewer fragmented species, as the average carbon number is higher and OSC‾ lower than cluster 2, and more species with an odd number of oxygen atoms. This suggests that clustering of time series which have features pertaining to distinct chemical regimes, for example, NO2/NOx perturbations, coupled with a priori knowledge, can provide insight into identification of potential functionality.
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- 2021
39. Evaluating the sensitivity of radical chemistry and ozone formation to ambient VOCs and NOₓ in Beijing
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Whalley, Lisa K., Slater, Eloise J., Woodward-Massey, Robert, Ye, Chunxiang, Lee, James D., Squires, Freya, Hopkins, James R., Dunmore, Rachel E., Shaw, Marvin, Hamilton, Jacqueline F., Lewis, Alastair C., Mehra, Archit, Worrall, Stephen D., Bacak, Asan, Bannan, Thomas J., Coe, Hugh, Percival, Carl J., Ouyang, Bin, Jones, Roderic L., Crilley, Leigh R., Kramer, Louisa J., Bloss, William J., Vu, Tuan, Kotthaus, Simone, Grimmond, Sue, Sun, Yele, Xu, Weiqi, Yue, Siyao, Ren, Lujie, Acton, W. Joe F., Hewitt, C. Nicholas, Wang, Xinming, Fu, Pingqing, and Heard, Dwayne E.
- Abstract
Measurements of OH, HO2, complex RO2 (alkene- and aromatic-related RO2) and total RO2 radicals taken during the integrated Study of AIR Pollution PROcesses in Beijing (AIRPRO) campaign in central Beijing in the summer of 2017, alongside observations of OH reactivity, are presented. The concentrations of radicals were elevated, with OH reaching up to 2.8×107moleculecm−3, HO2 peaking at 1×109moleculecm−3 and the total RO2 concentration reaching 5.5×109moleculecm−3. OH reactivity (k(OH)) peaked at 89 s−1 during the night, with a minimum during the afternoon of ≈22s−1 on average. An experimental budget analysis, in which the rates of production and destruction of the radicals are compared, highlighted that although the sources and sinks of OH were balanced under high NO concentrations, the OH sinks exceeded the known sources (by 15 ppbv h−1) under the very low NO conditions (
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- 2021
40. The influence of the addition of isoprene on the volatility of particles formed from the photo-oxidation of anthropogenic–biogenic mixtures.
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Voliotis, Aristeidis, Du, Mao, Wang, Yu, Shao, Yunqi, Bannan, Thomas J., Flynn, Michael, Pandis, Spyros N., Percival, Carl J., Alfarra, M. Rami, and McFiggans, Gordon
- Subjects
PINENE ,ISOPRENE ,SEMIVOLATILE organic compounds ,VOLATILE organic compounds ,COMPLEX compounds ,MASS spectrometers ,MIXTURES - Abstract
In this study, we investigate the influence of isoprene on the volatility of secondary organic aerosol (SOA) formed during the photo-oxidation of mixtures of anthropogenic and biogenic precursors. The SOA particle volatility was quantified using two independent experimental techniques (using a thermal denuder and the Filter Inlet for Gas and Aerosols iodide high-resolution time-of-flight Chemical Ionisation Mass Spectrometer – FIGAERO-CIMS) in mixtures of α -pinene/isoprene, o -cresol/isoprene, and α -pinene/ o -cresol/isoprene. Single-precursor experiments at various initial concentrations and results from previous α -pinene/ o -cresol experiments were used as a reference. The oxidation of isoprene did not result in the formation of detectable SOA particle mass in single-precursor experiments. However, isoprene-derived products were identified in the mixed systems, likely due to the increase in the total absorptive mass. The addition of isoprene resulted in mixture-dependent influence on the SOA particle volatility. Isoprene made no major change to the volatility of α -pinene SOA particles, though changes in the SOA particle composition were observed and the volatility was reasonably predicted based on the additivity. Isoprene addition increased o -cresol SOA particle volatility by ∼5/15 % of the total mass/signal, respectively, indicating a potential to increase the overall volatility that cannot be predicted based on the additivity. The addition of isoprene to the α -pinene/ o -cresol system (i.e. α -pinene/ o -cresol/isoprene) resulted in slightly fewer volatile particles than those measured in the α -pinene/ o -cresol systems. The measured volatility in the α -pinene/ o -cresol/isoprene system had an ∼6 % higher low volatile organic compound (LVOC) mass/signal compared to that predicted assuming additivity with a correspondingly lower semi-volatile organic compound (SVOC) fraction. This suggests that any effects that could increase the SOA volatility from the addition of isoprene are likely outweighed by the formation of lower-volatility compounds in more complex anthropogenic–biogenic precursor mixtures. Detailed chemical composition measurements support the measured volatility distribution changes and showed an abundance of unique-to-the-mixture products appearing in all the mixed systems accounting for around 30 %–40 % of the total particle-phase signal. Our results demonstrate that the SOA particle volatility and its prediction can be affected by the interactions of the oxidized products in mixed-precursor systems, and further mechanistic understanding is required to improve their representation in chemical transport models. [ABSTRACT FROM AUTHOR]
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- 2022
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41. Supplementary material to "Global tropospheric halogen (Cl, Br, I) chemistry and its impact on oxidants"
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Wang, Xuan, primary, Jacob, Daniel J., additional, Downs, William, additional, Zhai, Shuting, additional, Zhu, Lei, additional, Shah, Viral, additional, Holmes, Christopher D., additional, Sherwen, Tomás, additional, Alexander, Becky, additional, Evans, Mathew J., additional, Eastham, Sebastian D., additional, Neuman, J. Andrew, additional, Veres, Patrick, additional, Koenig, Theodore K., additional, Volkamer, Rainer, additional, Huey, L. Gregory, additional, Bannan, Thomas J., additional, Percival, Carl J., additional, Lee, Ben H., additional, and Thornton, Joel A., additional
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- 2021
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42. Supplementary Information: Details of flight paths and additional figures and photographs. from Isotopic signatures of methane emissions from tropical fires, agriculture and wetlands: the MOYA and ZWAMPS flights
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Nisbet, Euan G., Allen, Grant, Fisher, Rebecca E., France, James L., Lee, James D., Lowry, David, Andrade, Marcos F., Bannan, Thomas J., Barker, Patrick, Bateson, Prudence, Bauguitte, St��phane J.-B., Bower, Keith N., Broderick, Tim J., Chibesakunda, Francis, Cain, Michelle, Cozens, Alice E., Daly, Michael C., Ganesan, Anita L., Jones, Anna E., Lambakasa, Musa, Lunt, Mark F., Mehra, Archit, Moreno, Isabel, Pasternak, Dominika, Palmer, Paul I., Percival, Carl J., Pitt, Joseph R., Riddle, Amber J., Rigby, Matthew, Shaw, Jacob T., Stell, Angharad C., Vaughan, Adam R., Warwick, Nicola J., and Wilde, Shona
- Abstract
Supplementary Information: Isotopic signatures of methane emissions from tropical fires and wetlands: the MOYA and ZWAMPS flights. MOYA ZWAMPS team
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- 2021
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43. Measured Solid State and Sub-Cooled Liquid Vapour Pressures of Benzaldehydes Using Knudsen Effusion Mass Spectrometry
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Shelley, Petroc, Bannan, Thomas J., Worrall, Stephen D., Alfarra, M. Rami, Percival, Carl J., Garforth, Arthur, Topping, David, Shelley, Petroc, Bannan, Thomas J., Worrall, Stephen D., Alfarra, M. Rami, Percival, Carl J., Garforth, Arthur, and Topping, David
- Abstract
Benzaldehydes are components of atmospheric aerosol that are poorly represented in current vapour pressure predictive techniques. In this study the solid state ( and sub-cooled liquid saturation vapour pressures ) were measured over a range of temperatures (298–328 K) for a chemically diverse group of benzaldehydes. The selected benzaldehydes allowed for the effects of varied geometric isomers and functionalities on saturation vapour pressure () to be probed. was measured using Knudsen effusion mass spectrometry (KEMS) and was obtained via a sub-cooled correction utilising experimental enthalpy of fusion and melting point values measured using differential scanning calorimetry (DSC). The strength of the hydrogen bond (H-bond) was the most important factor for determining when a H-bond was present and the polarisability of the compound was the most important factor when a H-bond was not present. Typically compounds capable of hydrogen bonding had 1 to 2 orders of magnitude lower than those that could not H-bond. The were compared to estimated values using three different predictive techniques (Nannoolal et al. vapour pressure method, Myrdal and Yalkowsky method, and SIMPOL). The Nannoolal et al. vapour pressure method and the Myrdal and Yalkowsky method require the use of a boiling point method to predict . For the compounds in this study the Nannoolal et al. boiling point method showed the best performance. All three predictive techniques showed less than an order of magnitude error in on average, however more significant errors were within these methods. Such errors will have important implications for studies trying to ascertain the role of these compounds on aerosol growth and human health impacts. SIMPOL predicted the closest to the experimentally determined values.
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- 2021
44. Evaluating the sensitivity of radical chemistry and ozone formation to ambient VOCs and NOxin Beijing
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Whalley, Lisa K., Slater, Eloise J., Woodward-Massey, Robert, Ye, Chunxiang, Lee, James D., Squires, Freya, Hopkins, James R., Dunmore, Rachel E., Shaw, Marvin, Hamilton, Jacqueline F., Lewis, Alastair C., Mehra, Archit, Worrall, Stephen D., Bacak, Asan, Bannan, Thomas J., Coe, Hugh, Percival, Carl J., Ouyang, Bin, Jones, Roderic L., Crilley, Leigh R., Kramer, Louisa J., Bloss, William J., Vu, Tuan, Kotthaus, Simone, Grimmond, Sue, Sun, Yele, Xu, Weiqi, Yue, Siyao, Ren, Lujie, Joe, W., Nicholas Hewitt, C., Wang, Xinming, Fu, Pingqing, Heard, Dwayne E., Whalley, Lisa K., Slater, Eloise J., Woodward-Massey, Robert, Ye, Chunxiang, Lee, James D., Squires, Freya, Hopkins, James R., Dunmore, Rachel E., Shaw, Marvin, Hamilton, Jacqueline F., Lewis, Alastair C., Mehra, Archit, Worrall, Stephen D., Bacak, Asan, Bannan, Thomas J., Coe, Hugh, Percival, Carl J., Ouyang, Bin, Jones, Roderic L., Crilley, Leigh R., Kramer, Louisa J., Bloss, William J., Vu, Tuan, Kotthaus, Simone, Grimmond, Sue, Sun, Yele, Xu, Weiqi, Yue, Siyao, Ren, Lujie, Joe, W., Nicholas Hewitt, C., Wang, Xinming, Fu, Pingqing, and Heard, Dwayne E.
- Abstract
Measurements of OH, HO2, complex RO2 (alkene-and aromatic-related RO2) and total RO2 radicals taken during the integrated Study of AIR Pollution PROcesses in Beijing (AIRPRO) campaign in central Beijing in the summer of 2017, alongside observations of OH reactivity, are presented. The concentrations of radicals were elevated, with OH reaching up to 2:8 × 107 molecule cm-3, HO2 peaking at 1 × 109 molecule cm-3 and the total RO2 concentration reaching 5:5×109 molecule cm-3. OH reactivity (k.OH/) peaked at 89 s-1 during the night, with a minimum during the afternoon of 22s-1 on average. An experimental budget analysis, in which the rates of production and destruction of the radicals are compared, highlighted that although the sources and sinks of OH were balanced under high NO concentrations, the OH sinks exceeded the known sources (by 15 ppbvh-1) under the very low NO conditions (< 0:5ppbv) experienced in the afternoons, demonstrating a missing OH source consistent with previous studies under high volatile organic compound (VOC) emissions and low NO loadings. Under the highest NO mixing ratios (104 ppbv), the HO2 production rate exceeded the rate of destruction by 50ppbvh-1, whilst the rate of destruction of total RO2 exceeded the production by the same rate, indicating that the net propagation rate of RO2 to HO2 may be substantially slower than assumed. If just 10 % of the RO2 radicals propagate to HO2 upon reaction with NO, the HO2 and RO2 budgets could be closed at high NO, but at low NO this lower RO2 to HO2 propagation rate revealed a missing RO2 sink that was similar in magnitude to the missing OH source. A detailed box model that incorporated the latest Master Chemical Mechanism (MCM3.3.1) reproduced the observed OH concentrations well but over-predicted the observed HO2 under low concentrations of NO (< 1ppbv) and under-predicted RO2 (both the complex RO2 fraction and other RO2 types which we classify as simple RO2) most significantly at the highest NO concent
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- 2021
45. Low-NO atmospheric oxidation pathways in a polluted megacity
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Newland, Mike J., Bryant, Daniel J., Dunmore, Rachel E., Bannan, Thomas J., Joe, W., Langford, Ben, Hopkins, James R., Squires, Freya A., Dixon, William, Drysdale, William S., Ivatt, Peter D., Evans, Mathew J., Edwards, Peter M., Whalley, Lisa K., Heard, Dwayne E., Slater, Eloise J., Woodward-Massey, Robert, Ye, Chunxiang, Mehra, Archit, Worrall, Stephen D., Bacak, Asan, Coe, Hugh, Percival, Carl J., Nicholas Hewitt, C., Lee, James D., Cui, Tianqu, Surratt, Jason D., Wang, Xinming, Lewis, Alastair C., Rickard, Andrew R., Hamilton, Jacqueline F., Newland, Mike J., Bryant, Daniel J., Dunmore, Rachel E., Bannan, Thomas J., Joe, W., Langford, Ben, Hopkins, James R., Squires, Freya A., Dixon, William, Drysdale, William S., Ivatt, Peter D., Evans, Mathew J., Edwards, Peter M., Whalley, Lisa K., Heard, Dwayne E., Slater, Eloise J., Woodward-Massey, Robert, Ye, Chunxiang, Mehra, Archit, Worrall, Stephen D., Bacak, Asan, Coe, Hugh, Percival, Carl J., Nicholas Hewitt, C., Lee, James D., Cui, Tianqu, Surratt, Jason D., Wang, Xinming, Lewis, Alastair C., Rickard, Andrew R., and Hamilton, Jacqueline F.
- Abstract
The impact of emissions of volatile organic compounds (VOCs) to the atmosphere on the production of secondary pollutants, such as ozone and secondary organic aerosol (SOA), is mediated by the concentration of nitric oxide (NO). Polluted urban atmospheres are typically considered to be "high-NO"environments, while remote regions such as rainforests, with minimal anthropogenic influences, are considered to be "low NO". However, our observations from central Beijing show that this simplistic separation of regimes is flawed. Despite being in one of the largest megacities in the world, we observe formation of gas- and aerosol-phase oxidation products usually associated with low-NO "rainforest-like"atmospheric oxidation pathways during the afternoon, caused by extreme suppression of NO concentrations at this time. Box model calculations suggest that during the morning high-NO chemistry predominates (95 %) but in the afternoon low-NO chemistry plays a greater role (30 %). Current emissions inventories are applied in the GEOS-Chem model which shows that such models, when run at the regional scale, fail to accurately predict such an extreme diurnal cycle in the NO concentration. With increasing global emphasis on reducing air pollution, it is crucial for the modelling tools used to develop urban air quality policy to be able to accurately represent such extreme diurnal variations in NO to accurately predict the formation of pollutants such as SOA and ozone.
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- 2021
46. Using highly time-resolved online mass spectrometry to examine biogenic and anthropogenic contributions to organic aerosol in Beijing
- Author
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Mehra, Archit, Canagaratna, Manjula, Bannan, Thomas J., Worrall, Stephen D., Bacak, Asan, Priestley, Michael, Liu, Dantong, Zhao, Jian, Xu, Weiqi, Sun, Yele, Hamilton, Jacqueline F., Squires, Freya A., Lee, James, Bryant, Daniel J., Hopkins, James R., Elzein, Atallah, Budisulistiorini, Sri Hapsari, Cheng, Xi, Chen, Qi, Wang, Yuwei, Wang, Lin, Stark, Harald, Krechmer, Jordan E., Brean, James, Slater, Eloise, Whalley, Lisa, Heard, Dwayne, Ouyang, Bin, Acton, W. Joe F., Hewitt, C. Nicholas, Wang, Xinming, Fu, Pingqing, Jayne, John, Worsnop, Douglas, Allan, James, Percival, Carl, Coe, Hugh, Mehra, Archit, Canagaratna, Manjula, Bannan, Thomas J., Worrall, Stephen D., Bacak, Asan, Priestley, Michael, Liu, Dantong, Zhao, Jian, Xu, Weiqi, Sun, Yele, Hamilton, Jacqueline F., Squires, Freya A., Lee, James, Bryant, Daniel J., Hopkins, James R., Elzein, Atallah, Budisulistiorini, Sri Hapsari, Cheng, Xi, Chen, Qi, Wang, Yuwei, Wang, Lin, Stark, Harald, Krechmer, Jordan E., Brean, James, Slater, Eloise, Whalley, Lisa, Heard, Dwayne, Ouyang, Bin, Acton, W. Joe F., Hewitt, C. Nicholas, Wang, Xinming, Fu, Pingqing, Jayne, John, Worsnop, Douglas, Allan, James, Percival, Carl, and Coe, Hugh
- Abstract
Organic aerosols, a major constituent of fine particulate mass in megacities, can be directly emitted or formed from secondary processing of biogenic and anthropogenic volatile organic compound emissions. The complexity of volatile organic compound emission sources, speciation and oxidation pathways leads to uncertainties in the key sources and chemistry leading to formation of organic aerosol in urban areas. Historically, online measurements of organic aerosol composition have been unable to resolve specific markers of volatile organic compound oxidation, while offline analysis of markers focus on a small proportion of organic aerosol and lack the time resolution to carry out detailed statistical analysis required to study the dynamic changes in aerosol sources and chemistry. Here we use data collected as part of the joint UK–China Air Pollution and Human Health (APHH-Beijing) collaboration during a field campaign in urban Beijing in the summer of 2017 alongside laboratory measurements of secondary organic aerosol from oxidation of key aromatic precursors (1,3,5-trimethyl benzene, 1,2,4-trimethyl benzene, propyl benzene, isopropyl benzene and 1-methyl naphthalene) to study the anthropogenic and biogenic contributions to organic aerosol. For the first time in Beijing, this study applies positive matrix factorisation to online measurements of organic aerosol composition from a time-of-flight iodide chemical ionisation mass spectrometer fitted with a filter inlet for gases and aerosols (FIGAERO-ToF-I-CIMS). This approach identifies the real-time variations in sources and oxidation processes influencing aerosol composition at a near-molecular level. We identify eight factors with distinct temporal variability, highlighting episodic differences in OA composition attributed to regional influences and in situ formation. These have average carbon numbers ranging from C5–C9 and can be associated with oxidation of anthropogenic aromatic hydrocarbons alongside biogenic emissi
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- 2021
47. Evaluating the sensitivity of radical chemistry and ozone formation to ambient VOCs and NOx in Beijing
- Author
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Whalley, Lisa, Slater, Eloise, Woodward-Massey, Robert, Ye, Chunxiang, Lee, James D., Squires, Freya, Hopkins, James R., Dunmore, Rachel E., Shaw, Marvin, Hamilton, Jacqueline F., Lewis, Alastair C., Mehra, Archit, Worrall, Stephen David, Bacak, Asan, Bannan, Thomas J., Coe, Hugh, Ouyang, Bin, Jones, Roderic L., Crilley, Leigh R., Kramer, Louisa J., Bloss, William J., Vu, Tuan, Kotthaus, Simone, Grimmond, Sue, Sun, Yele, Xu, Weiqi, Yue, Siyao, Ren, Lujie, Acton, W Joe F, Hewitt, C N, Wang, Xinming, Fu, Pingqing, Heard, Dwayne E., Whalley, Lisa, Slater, Eloise, Woodward-Massey, Robert, Ye, Chunxiang, Lee, James D., Squires, Freya, Hopkins, James R., Dunmore, Rachel E., Shaw, Marvin, Hamilton, Jacqueline F., Lewis, Alastair C., Mehra, Archit, Worrall, Stephen David, Bacak, Asan, Bannan, Thomas J., Coe, Hugh, Ouyang, Bin, Jones, Roderic L., Crilley, Leigh R., Kramer, Louisa J., Bloss, William J., Vu, Tuan, Kotthaus, Simone, Grimmond, Sue, Sun, Yele, Xu, Weiqi, Yue, Siyao, Ren, Lujie, Acton, W Joe F, Hewitt, C N, Wang, Xinming, Fu, Pingqing, and Heard, Dwayne E.
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- 2021
48. Supplementary material to "Improvements to the representation of BVOC chemistry-climate interactions in UKCA (vn11.5) with the CRI-Strat 2 mechanism: Incorporation and Evaluation "
- Author
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Weber, James, primary, Archer-Nicholls, Scott, additional, Abraham, Nathan Luke, additional, Shin, Youngsub Matthew, additional, Bannan, Thomas J., additional, Percival, Carl J., additional, Bacak, Asan, additional, Artaxo, Paulo, additional, Jenkin, Michael, additional, Khan, M. Anwar H., additional, Shallcross, Dudley E., additional, Schwantes, Rebecca H., additional, Williams, Jonathan, additional, and Archibald, Alex T., additional
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- 2021
- Full Text
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49. The influence of the addition of a reactive low SOA yield VOC on the volatility of particles formed from photo-oxidation of anthropogenic - biogenic mixtures.
- Author
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Voliotis, Aristeidis, Mao Du, Yu Wang, Yunqi Shao, Bannan, Thomas J., Flynn, Michael, Pandis, Spyros N., Percival, Carl J., Alfarra, M. Rami, and McFiggans, Gordon
- Abstract
In this study, we investigate the influence of isoprene on the volatility of secondary organic aerosol (SOA) formed during the photo-oxidation of mixtures of anthropogenic and biogenic precursors. The SOA particle volatility was quantified using two independent experimental techniques (use of a thermal denuder and FIGAERO-CIMS) in mixtures of a-pinene/isoprene, o-cresol/isoprene and a-pinene/o-cresol/isoprene. Single-precursor experiments at various initial concentrations and results from previous a-pinene/o-cresol experiments were used as reference. The oxidation of isoprene did not result in the formation of detectable SOA mass in single-precursor experiments, however isoprene-derived products appeared in mixed systems, likely due to the increase in the total absorptive mass. Addition of isoprene resulted in mixturedependent influence on the SOA particle volatility. Isoprene made no major change to the volatility of a-pinene SOA particles though changes in the SOA particle composition were observed, with volatility predicted reasonably based on the additivity. Isoprene addition increased o-cresol SOA particle volatility by ~5/15% of the total mass/signal, respectively, indicating a potential to increase the overall volatility that cannot be predicted based on the additivity. The addition of isoprene to the a-pinene/o-cresol system (i.e., a-pinene/o-cresol/isoprene) resulted in slightly less-volatile particles than those measured in the a-pinene/o-cresol systems. The measured volatility in the a-pinene/o-cresol/isoprene system had ~6% higher LVOC mass/signal compared to that predicted assuming additivity with a correspondingly lower SVOC fraction. This suggests that any effects that could increase the SOA volatility from the addition of isoprene are likely outweighed from the formation of lower volatility compounds in more complex anthropogenic-biogenic precursor mixtures. Detailed chemical composition measurements support the measured volatility distribution changes and showed an abundance of unique-to-themixture products appearing in all the mixed systems accounting for around 30-40% of the total particle phase signal. Our results demonstrate that the SOA particle volatility and its prediction can be affected by the interactions of the oxidised products in mixed precursor systems and further mechanistic understanding is required to improve their representation in chemical transport models. [ABSTRACT FROM AUTHOR]
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- 2022
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50. Measured Solid State and Sub-Cooled Liquid Vapour Pressures of Benzaldehydes Using Knudsen Effusion Mass Spectrometry
- Author
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Shelley, Petroc, primary, Bannan, Thomas J., additional, Worrall, Stephen D., additional, Alfarra, M. Rami, additional, Percival, Carl J., additional, Garforth, Arthur, additional, and Topping, David, additional
- Published
- 2021
- Full Text
- View/download PDF
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