#jsDisabledContent { display:none; } My Account | Register | Help

 Add to Book Shelf Flag as Inappropriate This book will be permanently flagged as inappropriate and made unaccessible to everyone. Are you certain this book is inappropriate?          Excessive Violence          Sexual Content          Political / Social Email this Book Email Address:

# Impact of Dust on Tropospheric Photochemistry Over Polluted Regions: a Case Study of the Beijing Megacity : Volume 9, Issue 5 (25/09/2009)

## By Zhu, S.

Book Id: WPLBN0003976933
File Size: Pages 50
Reproduction Date: 2015

 Title: Impact of Dust on Tropospheric Photochemistry Over Polluted Regions: a Case Study of the Beijing Megacity : Volume 9, Issue 5 (25/09/2009) Author: Zhu, S. Volume: Vol. 9, Issue 5 Language: English Subject: Collections: Historic Publication Date: 2009 Publisher: Copernicus Gmbh, Göttingen, Germany Member Page: Copernicus Publications Citation APA MLA Chicago Sander, R., Butler, T., Ma, J., Lawrence, M. G., & Zhu, S. (2009). Impact of Dust on Tropospheric Photochemistry Over Polluted Regions: a Case Study of the Beijing Megacity : Volume 9, Issue 5 (25/09/2009). Retrieved from http://ebooklibrary.org/

Description
Description: Chinese Academy of Meteorological Sciences, Beijing, China. The box model MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere) is updated by incorporating detailed heterogeneous chemistry occurring on mineral aerosol surfaces. The model is used to investigate the impact of dust on tropospheric photochemistry, when the dust is transported to a polluted region together with other trace gases. The impacts of dust via heterogeneous removal of gases are analyzed for different hypothetical transport rates which are described by four different exchange rate coefficients Kt in the model. Substantial impacts are found for many gases, including Ox (O3+O(3P), NOx (NO+NO2) and OH. The Ox daily average mixing ratio decreases due to heterogeneous reactions on dust. The change ranges from –2.5 to –18.4 nmol/mol, and is larger for faster mixing with upwind air masses (i.e. greater Kt). This translates into a large relative change in Ox, ranging from –44% to –55%, which changes slightly with increasing values of Kt. By assuming an artificial 50% decrease of all photolysis rates, the impacts of dust via photolysis perturbation are also estimated. Furthermore, the uncertainties in the results due to the uncertainties in the uptake coefficients are evaluated. It is found that for all gases which are heterogeneously removed, the self-removal results in the largest uncertainty (e.g. –49% for O3, –76% for NO2, –47% for HNO3, –92% for HCHO, –64% for CH3OH and –93% for SO2). The heterogeneous removal of NO2 is found to be particularly important, because it results in significant uncertainties not only in itself, but also in OH (340%) and HO2 (365%). Moreover, the heterogeneous removal of HCHO and O3 also has farther-reaching effects on the OH concentration (resulting in changes of –55% and 45%, respectively), and the heterogeneous removal of HCHO results in an uncertainty of –38% in the HO2 concentration.

Summary
Impact of dust on tropospheric photochemistry over polluted regions: a case study of the Beijing megacity

Excerpt
Adams, J. W., Rodriguez, D., and Cox, R. A.: The uptake of SO2 on Saharan dust: a flow tube study, Atmos. Chem. Phys., 5, 2679–2689, 2005.; Bauer, S. E., Balkanski, Y., Schulz, M., and Haughlustaine, D. A.: Global modeling of heterogeneous chemistry on mineral aerosol surfaces: Influence on tropospheric ozone chemistry and comparison to observations, J. Geophys. Res., 109, D02304, doi:10.1029/2003JD003868, 2004.; Bian, H. and Zender, C. S.: Mineral dust and global tropospheric chemistry: Relative roles of photolysis and heterogeneous uptake, J. Geophys. Res., 108(D21), 4672, doi:10.1029/2002JD003143, 2003.; Carlos-Cuellar, S., Li, P., Christensen, A. P., Krueger, B. J., Burrichter, C., and Grassian, V. H.: Heterogeneous uptake kinetics of volatile organic compounds on oxide surfaces using a Knudsen cell reactor: Adsorption of acetic acid, formaldehyde, and methanol on $\alpha$-\chem{Fe_{2}O_{3}}, α-\chem{Al_{2}O_{3}}, and SiO2, J. Phys. Chem. A, 107, 4250–4261, 2003.; Crutzen, P. J. and Schmailzl, U.: Chemical budgets of the stratosphere, Planet. Space. Sci., 31, 1009–1032, 1983.; Dentener, F. J., Carmichael, G. R., Zhang, Y., Lelieveld, J., and Crutzen, P. J.: Role of mineral aerosol as a reactive surface in the global troposphere, J. Geophys. Res., 101, 22869–22889, 1996.; de Reus, M., Dentener, F., Thomas, A., Borrmann, S., Ström, J., and Lelieveld, J.: Airborne observations of dust aerosol over the North Atlantic Ocean during ACE-2: Indications for heterogeneous ozone destruction, J. Geophys. Res., 105, 15263–15275, 2000.; Kaufman, Y. J., Tanré, D., and Boucher, O.: A satellite view of aerosols in the climate system, Nature, 419, 215–223, 2002.; de Reus, M., Fischer, H., Sander, R., Gros, V., Kormann, R., Salisbury, G., Van Dingenen, R., Williams, J., Zöllner, M., and Lelieveld, J.: Observations and model calculations of trace gas scavenging in a dense Saharan dust plume during MINATROC, Atmos. Chem. Phys., 5, 1787–1803, 2005.; DeMore, W. B., Sander, S. P., Golden, D. M., Hampson, R. F., Kurylo, M. J., Howard, C. J., Ravishankara, A. R., Kolb, C. E., and Molina, M. J.: Chemical kinetics and photochemical data for use in stratospheric modeling, National Aeronautics and Space Administration and Jet Propulsion Laboratory, California Institute of Technology, California, 1997.; Fuchs, N. A. and Sutugin, A. G.: Highly Dispersed Aerosols, Butterworth-Heinemann, Woburn, Mass., 1970.; Gong, S. L., Zhang, X. Y., Zhao, T. L., Zhang, X., McKendry, I. G., and Zhao, C. S.: A simulated climatology of Asian dust aerosol and its trans-Pacific transport: 2. Interannual Variability and Climate Connections, J. Climate, 19, 104–122, 2006.; Goodman, A. L., Underwood, G. M., and Grassian, V. H.: A laboratory study of the heterogeneous reaction of nitric acid on calcium carbonate particles, J. Geophys. Res., 105(D23), 29053–29064, 2000.; Grassian, V. H.: Chemical reactions of nitrogen oxides on the surface of oxide, carbonate, soot, and mineral dust particles: Implications for the chemical balance of the troposphere, J. Phys. Chem.&am