Journal of Atmospheric Chemistry

, Volume 52, Issue 2, pp 165–183

Urban Atmospheric Chemistry During the PUMA Campaign 2: Radical Budgets for OH, HO2 and RO2

Article

Abstract

A detailed photochemical box model was used to investigate the key reaction pathways between OH, HO2 and RO2 radicals during the summer and winter PUMA field campaigns in the urban city-centre of Birmingham in the UK. The model employed the most recent version of the Master Chemical Mechanism and was constrained to 15-minute average measurements of long-lived species determined in situ at the site. The results showed that in the summer, OH initiation was dominated by the reactions of ozone with alkenes, nitrous acid (HONO) photolysis and the reaction of excited oxygen atoms atoms with water. In the winter, ozone+alkene reactions were the primary initiation route, with a minor contribution from HONO photolysis. Photolysis of aldehydes was the main initiation route for HO2, in both summer and winter. RO2 initiation was dominated by the photolysis of aldehydes in the summer with a smaller contribution from ozone+alkenes, a situation that was reversed in the winter. At night, ozone+alkene reactions were the main radical source. Termination, under all conditions, primarily involved reactions with NO (OH) and NO2 (OH and RCO3). These results demonstrate the importance of ozone+alkene reactions in urban atmospheres, particularly when photolysis reactions were less important during winter and at nighttime. The implications for urban atmospheric chemistry are discussed.

Keywords

rate of production analysis OH radical ozone+alkene reactions urban air quality 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Carslaw, N., Creasey, D. J., Harrison, D., Heard, D. E., Hunter, M. C., Jacobs, P. J., Jenkin, M. E., Lee, J. D., Lewis, A. C., Pilling, M. J., Saunders, S. M., and Seakins, P. W., 2001: Modelling OH and HO2 radicals in a forested region of north-western Greece, Atmos. Environ. 35, 4725-4737.Google Scholar
  2. Collins, W. J., Stevenson, D. S., Johnson, C. E., and Derwent, R. G., 2000: The European regional ozone distribution and its links with the global scale for the years 1992 and 2015, Atmos. Environ. 34, 255–267.Google Scholar
  3. Emmerson, K. M., Carslaw, N., Carpenter, L. J., Heard, D. E., Lee, J. D., and Pilling, M. J., 2005: Urban atmospheric chemistry during the PUMA campaign. 1: comparison of modelled OH and HO2 concentrations with measurements. Submitted to Journal of Atmospheric Chemistry.Google Scholar
  4. Faloona, I., Tan, D., Brune, W., Hurst, J., Barket, D., Couch, T. L., Shepson, P., Apel, E., Riemer, D., Thornberry, T., Carroll, M. A., Sillman, S., Keeler, G. J., Sagady, J., Hooper, D., and Paterson, K., 2001: Nighttime observations of anomalously high levels of hydroxyl radicals above a deciduous forest canopy, J. Geophys. Res. 106(D20), 24,315–24,333.CrossRefGoogle Scholar
  5. Geyer, A., Bachmann, K., Hofzumahaus, A., Holland, F., Konrad, S., Klupfel, T., Patz, H. W., Perner, D., Mihelcic, D., Schafer, H. J., Volz-Thomas, A., and Platt, U., 2003: Nighttime formation of peroxy and hydroxyl radicals during the BERLIOZ campaign: Observations and modeling studies, J. Geophys. Res. 108(D4), 8249, doi:10.1029/2001JD000656CrossRefGoogle Scholar
  6. Harrison, R. M., Yin, J., Tilling, R. M., Cai, X., Seakins, P. W., Hopkins, J. R., Lansley, D. L., Hunter, M. C., Pilling, M. J., Carslaw, N., Emmerson, K. M., Redington, A., Derwent, R. G., Ryall, D., Mills, G., and Penkett, S. A., 2004: Measurement and modelling of air pollution and atmospheric chemistry in the UK West midlands conurbation: Overview of the PUMA consortium project. In press in Science of the Total Environment.Google Scholar
  7. Heard, D. E., Carpenter, L. J., Creasey, D. J., Hopkins, J. R., Lee, J. D., Lewis, A. C., Pilling, M. J., Seakins, P. W., Carslaw, N., and Emmerson, K. M., 2004: High levels of the hydroxyl radical in the winter urban troposphere, Geophys. Res. Lett. 31. L18112. doi:10.1029/2004GL02044
  8. Jenkin, M. E., Saunders, S. M., Wagner, V., and Pilling, M. J., 2003: Protocol for the development of the master chemical mechanism, MCM v3 (Part B): tropospheric degradation of aromatic volatile organic compounds, Atmos. Chem. and Phys. 3, 181–193.Google Scholar
  9. Jenkin, M. E., Saunders, S. M., and Pilling, M. J. 1997: The tropospheric degradation of volatile organic compounds: A protocol for mechanism development, Atmos. Environ, 31, 81–104.CrossRefGoogle Scholar
  10. Martinez, M., et al., 2003: OH and HO2 concentrations, sources, and loss rates during the Southern oxidants study in Nashville, Tennessee, summer 1999, J. Geophys. Res. 108. DOI:10.1029/2003JD003551Google Scholar
  11. Paulson, S. E., Chung, M., Sen, A. D., and Orzechowska, G. 1998: Measurement of OH radical formation from the reaction of ozone with several biogenic alkenes, J. Geophys. Res. 103, 25533–25539.CrossRefGoogle Scholar
  12. Platt, U., Alicke, B., Dubois, R., Geyer, A., Hofzumahaus, A., Holland, F., Martinez, M., Mihelcic, D., Klupfel, T., Lohrmann, B., Patz, W., Perner, D., Rohrer, F., Schafer, J., and Stutz, J., 2002: Free radicals and fast photochemistry during BERLIOZ, J. Atm. Chem. 42(1), 359–394.Google Scholar
  13. Ren, X., Harder, H., Martinez, M., Lesher, R. L., Oliger, A., Simpas, J. B., Brune, W. H., Schwab, J. J., Demerjian, K. L., He, Y., Zhou, X., and Gao, H., 2003: OH and HO2 chemistry in the urban atmosphere of New York City, Atmos. Environ. 37, 3639–3651.Google Scholar
  14. Saliba, N. A., Mochida, M., and Finlayson-Pitts, B. J., 2000: Laboratory studies of sources of HONO in polluted urban atmospheres, Geophys. Res. Letts. 27, 3229–3232.CrossRefGoogle Scholar
  15. Saunders, S. M., Jenkin, M. E., Derwent, R. G., and Pilling, M. J., 2003: Protocol for the development of the Master Chemical Mechanism, MCM v3 (Part A): Tropospheric degradation of non-aromatic volatile organic compounds. Atmos. Chem. and Phys, 3, 161–180.Google Scholar
  16. Sillman, S., 1999: The relation between ozone, NOX and hydrocarbons in urban and polluted rural environments, Atmos. Environ. 33, 1821–1845.CrossRefGoogle Scholar
  17. Tan, D., Faloona, I., Simpas, J. B., Brune, W., Shepson, P. B., Couch, T. L., Sumner, A. L., Carroll, M. A., Thornberry, T., Apel, E., Riemer, D., and Stockwell, W. J. 2001: HOx budgets in a deciduous forest: Results from the PROPHET summer campaign, Geophys. Res-A. 106, 24407.Google Scholar

Copyright information

© Springer Science + Business Media, Inc. 2005

Authors and Affiliations

  1. 1.Department of EnvironmentUniversity of YorkYorkU.K.
  2. 2.School of ChemistryUniversity of LeedsLeeds

Personalised recommendations