@article {48001, title = {Ozone air quality during the 2008 Beijing Olympics: Effectiveness of emission restrictions}, journal = {Atmospheric Chemistry and Physics}, volume = {9}, year = {2009}, note = {Final Manuscript in DASH}, pages = {5237-5251}, abstract = {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 O3, CO, NOy, and SO2 during August 2008, relative
to August 2006{\textendash}2007. The mean daytime mixing ratio
of O3 was lower by about 15 ppbv, reduced to 50 ppbv, in
August 2008. The relative reductions in daytime SO2, CO,
and NOy were 61\%, 25\%, and 21\%, respectively. Changes in
SO2 and in species correlations from 2007 to 2008 indicate
that emissions of SO2, CO, and NOx 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 O3 during August
2008, accounting for 80\% of the O3 reduction for the
month as a whole and 45\% during the Olympics Period (8{\textendash}
24 August). The model predicts that emission restrictions
such as those implemented during the Olympics can affect
O3 far beyond the Beijing urban area, resulting in reductions
in boundary layer O3 of 2{\textendash}10 ppbv over a large region of the
North China Plain and Northeastern China.}, url = {http://www.atmos-chem-phys.net/9/5237/2009/acp-9-5237-2009.pdf}, author = {Wang, Yuxuan and Hao, Jiming and McElroy, Michael B. and J. William Munger and Ma, Hong and Chen, Dan and Nielsen, Chris P} }