ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-9-5237-2009 Ozone air quality during the 2008 Beijing Olympics: effectiveness of emission restrictions Wang Y. 1 2 Hao J. 1 McElroy M. B. 2 Munger J. W. 2 Ma H. 1 Chen D. 1 Nielsen C. P. 3 Department of Environmental Science and Engineering and State Key Joint Laboratory of Environment Simulation and Pollution, Tsinghua University, Beijing, China Department of Earth and Planetary Sciences and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA Harvard China Project and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA 29 07 2009 9 14 5237 5251 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/9/5237/2009/acp-9-5237-2009.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/9/5237/2009/acp-9-5237-2009.pdf

A series of aggressive measures was launched by the Chinese government to reduce pollutant emissions from Beijing and surrounding areas during the Olympic Games. Observations at Miyun, a rural site 100 km downwind of the Beijing urban center, show significant decreases in concentrations of O<sub>3</sub>, CO, NO<sub>y</sub>, and SO<sub>2</sub> during August 2008, relative to August 2006–2007. The mean daytime mixing ratio of O<sub>3</sub> was lower by about 15 ppbv, reduced to 50 ppbv, in August 2008. The relative reductions in daytime SO<sub>2</sub>, CO, and NO<sub>y</sub> were 61%, 25%, and 21%, respectively. Changes in SO<sub>2</sub> and in species correlations from 2007 to 2008 indicate that emissions of SO<sub>2</sub>, CO, and NO<sub>x</sub> were reduced at least by 60%, 32%, and 36%, respectively, during the Olympics. Analysis of meteorological conditions and interpretation of observations using a chemical transport model suggest that although the day-to-day variability in ozone is driven mostly by meteorology, the reduction in emissions of ozone precursors associated with the Olympic Games had a significant contribution to the observed decrease in O<sub>3</sub> during August 2008, accounting for 80% of the O<sub>3</sub> reduction for the month as a whole and 45% during the Olympics Period (8–24 August). The model predicts that emission restrictions such as those implemented during the Olympics can affect O<sub>3</sub> far beyond the Beijing urban area, resulting in reductions in boundary layer O<sub>3</sub> of 2–10 ppbv over a large region of the North China Plain and Northeastern China.

 References Beirle, S., Platt, U., Wenig, M., and Wagner, T.: Weekly cycle of NO<sub>2</sub> by GOME measurements: a signature of anthropogenic sources, Atmos. Chem. Phys., 3, 2225–2232, 2003. Bey, I., Jacob, D. J., Yantosca, R. M., Logan, J. A., Field, B., Fiore, A. M., Li,, Q., Liu, H., Mickley, L. J., and Schultz, M.: Global modeling of tropospheric chemistry with assimilated meteorology: Model description and evaluation, J. Geophys. Res., 106, 23073–23096, 2001. Chen, D., Wang, Y., McElroy, M. B., He, K., Yantosca, R. M., and Le Sager, P.: Regional CO pollution and export in China simulated by the high-resolution nested-grid GEOS-Chem model, Atmos. Chem. Phys., 9, 3825–3839, 2009. Cheng, Y. F., Heintzenberg, J., Wehner, B., Wu, Z. J., Su, H., Hu, M., and Mao, J. T.: Traffic restrictions in Beijing during the Sino-African Summit 2006: aerosol size distribution and visibility compared to long-term in situ observations, Atmos. Chem. Phys., 8, 7583–7594, 2008. Chou, C. C.-K., Tsai, C.-Y., Shiu, C.-J., Liu, S. C., and Zhu, T.: Measurement of NO<sub>y</sub> during Campaign of Air Quality Research in Beijing~2006 (CAREBeijing-2006): Implications for the ozone production efficiency of NO<sub>x</sub>, J. Geophys. Res., 114, D00G01, doi:10.1029/2008JD010446, 2009. Davis, J. M. and Speckman, P.: A model for predicting maximum and 8 h average ozone in Houston, Atmos. Environ., 33, 2487–2500, 1999. Ding, A. J., Wang, T., Thouret, V., Cammas, J.-P., and Nédélec, P.: Tropospheric ozone climatology over Beijing: analysis of aircraft data from the MOZAIC program, Atmos. Chem. Phys. Discuss., 7, 9795–9828, 2007. Elminir, H. K.: Dependence of urban air pollutants on meteorology, Sci. Total Environ., 350, 225–237, 2005. Hao, J. M. and Wang, L. T.: Improving urban air quality in China: Beijing case study, J. Air Waste Manage., 55, 1298–1305, 2005. Harley, R. A., Marr, L. C., Lehner, J. K., and Giddings, S. N.: Changes in motor vehicle emissions on diurnal to decadal time scales and effects on atmospheric composition, Environ. Sci. Technol., 39, 5356–5362, 2005. Hirsch, R. M. and Gilroy, E. J.: Methods of fitting a straight line to data: Examples in water resources, Water Resour. Bull., 20, 705–711, 1984. Lin, W., Xu, X., Zhang, X., and Tang, J.: Contributions of pollutants from North China Plain to surface ozone at the Shangdianzi GAW Station, Atmos. Chem. Phys., 8, 5889–5898, 2008. Murphy, J. G., Day, D. A., Cleary, P. A., Wooldridge, P. J., Millet, D. B., Goldstein, A. H., and Cohen, R. C.: The weekend effect within and downwind of Sacramento: Part 2, Observational evidence for chemical and dynamical contributions, Atmos. Chem. Phys. Discuss., 6, 11971–12019, 2006. Murphy, J. G., Day, D. A., Cleary, P. A., Wooldridge, P. J., Millet, D. B., Goldstein, A. H., and Cohen, R. C.: The weekend effect within and downwind of Sacramento - Part 1: Observations of ozone, nitrogen oxides, and VOC reactivity, Atmos. Chem. Phys., 7, 5327–5339, 2007. NRC (National Research Council): Rethinking the ozone problem in urban and regional air pollution, National Academy Press, Washington, D.C., 1991. Ohara, T., Akimoto, H., Kurokawa, J., Horii, N., Yamaji, K., Yan, X., and Hayasaka, T.: An Asian emission inventory of \mboxanthropogenic emission sources for the period 1980-2020, Atmos. Chem. Phys., 7, 4419–4444, 2007. Platnick, S., King, M. D., Ackerman, S. A., Menzel, W. P., Baum, B. A., Riedi, J. C., and Frey, R. A.: The MODIS cloud products: Algorithms and examples from Terra, IEEE Trans. Geosci. Remote Sens., 41(2), 459–473, 2003. Sillman, S., Logan, J. A., and Wofsy, S. C.: The sensitivity of ozone to nitrogen oxides and hydrocarbons in regional ozone episodes, J. Geophys. Res., 95, 1837–1852, 1990. Sillman, S.: The Use of NOy, H<sub>2</sub>O<sub>2</sub>, and HNO<sub>3</sub> as indicators for ozone-NO<sub>x</sub>-hydrocarbon sensitivity in urban locations, J. Geophys. Res., 100, 14175–14188, 1995. Streets, D. G., Fu, J. H. S., Jang, C. J., Hao, J. M., He, K. B., Tang, X. Y., Zhang, Y. H., Wang, Z. F., Li, Z. P., Zhang, Q., Wang, L. T., Wang, B. Y., and Yu, C. Air quality during the 2008 Beijing Olympic Games, Atmos. Environ., 41(3), 480–492, 2007. Trainer, M., Parrish, D. D., Goldan, P. D., Roberts, J., and Fehsenfeld, F.C.: Review of observation-based analysis of the regional factors influencing ozone concentrations, Atmos. Environ., 34, 2045–2061, 2000. Wang, L. T., Hao, J. M., He, K. B., Wang, S. X., Li, J. H., Zhang, Q., Streets, D. G., Fu, J. S., Jang, C. J., Takekawa, H., and Chatani, S.: A modeling study of coarse particulate matter pollution in Beijing: Regional source contributions and control implications for the 2008 summer Olympics, J. Air Waste Manage., 58(8), 1057–1069, 2008a. Wang, T., Ding, A., Gao, J., and Wu, W. S.: Strong ozone production in urban plumes from Beijing, China, Geophys. Res. Lett., 33, L21806, doi:10.1029/2006GL027689, 2006. Wang, Y. X., McElroy, M. B., Jacob, D. J., and Yantosca, R. M.: A nested grid formulation for chemical transport over Asia: Applications to CO, J. Geophys. Res., 109, D22307, doi:10.1029/2004JD005237, 2004a. Wang, Y. X., McElroy, M. B., Wang, T., and Palmer, P. I.: Asian emissions of CO and NO<sub>x</sub>: Constraints from aircraft and Chinese station data, J. Geophys. Res., 109, D24304, doi:10.1029/2004JD005250, 2004b. Wang, Y., McElroy, M. B., Munger, J. W., Hao, J., Ma, H., Nielsen, C. P., and Chen, Y.: Variations of O<sub>3</sub> and CO in summertime at a rural site near Beijing, Atmos. Chem. Phys., 8, 6355–6363, 2008. Wild, O., Zhu, X., Prather, M. J., and Fast, J.: Accurate simulation of in- and below cloud photolysis in tropospheric chemical models, J. Atmos. Chem., 37, 245–282, 2000. Zhang, Q., Streets, D. G., He, K., et al.: NO<sub>x</sub> emission trends for China, 1995–2004: The view from the ground and the view from space, J. Geophys. Res., D22306, doi:10.1029/2007JD008684, 2007. Zhang, Q., Streets, D. G., Carmichael, G. R., He, K., Huo, H., Kannari, A., Klimont, Z., Park, I., Reddy, S., Fu, J. S., Chen, D., Duan, L., Lei, Y., Wang, L., and Yao, Z.: Asian emissions in 2006 for the NASA INTEX-B mission, Atmos. Chem. Phys. Discuss., 9, 4081–4139, 2009. Zhao, Y., Wang, S. X., Duan, L., et al.: Primary air pollutant emissions of coal-fired power plants in China: Current status and future prediction, Atmos. Environ., 42, 8442–8452, 2008.