Yuxuan Wang, Jiming Hao, Michael B. McElroy, J. William Munger, Hong Ma, Dan Chen, and Chris P Nielsen. 2009. “
Ozone air quality during the 2008 Beijing Olympics: Effectiveness of emission restrictions.” Atmospheric Chemistry and Physics, 9, 14, Pp. 5237-5251.
Publisher's VersionAbstractA 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 2006–2007. 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–
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 2–10 ppbv over a large region of the
North China Plain and Northeastern China.
Michael B. McElroy, Xi Lu, Chris P Nielsen, and Yuxuan Wang. 2009. “
Potential for wind generated electricity in China.” Science, 325, 5946, Pp. 1378-1380.
Publisher's VersionAbstractWind offers an important alternative to coal as a source of energy for generation of electricity in China with the potential for substantial savings in carbon dioxide emissions. Wind fields derived from assimilated meteorological data are used to assess the potential for wind-generated electricity in China subject to the existing government-approved bidding process for new wind farms. Assuming a guaranteed price of 0.516 RMB (7.6 U.S. cents) per kilowatt-hour for delivery of electricity to the grid over an agreed initial average period of 10 years, it is concluded that wind could accommodate all of the demand for electricity projected for 2030, about twice current consumption. Electricity available at a concession price as low as 0.4 RMB per kilowatt-hour would be sufficient to displace 23% of electricity generated from coal.
Dan Chen, Yuxuan Wang, Michael B. McElroy, Kebin He, Robert M Yantosca, and Phillipe Le Sager. 2009. “
Regional CO pollution in China simulated by the high-resolution nested-grid GEOS-Chem model.” Atmospheric Chemistry and Physics, 9, 11, Pp. 3825-3839.
Publisher's VersionAbstractAn updated version of the nested-grid GEOSChem
model is developed allowing for higher horizontal
(0.5×0.667) resolution as compared to global models. CO
transport over a heavily polluted region, the Beijing-Tianjin-
Hebei (BTH) city cluster in China, and the pattern of outflow
from East China in summertime are investigated. Comparison
of the nested-grid with global models indicates that the
fine-resolution nested-grid model is capable of resolving individual
cities with high associated emission intensities. The
nested-grid model indicates the presence of a high CO column
density over the Sichuan Basin in summer, attributable
to the low-level stationary vortex associated with the Basin’s
topographical features. The nested-grid model provides good
agreement also with measurements from a suburban monitoring
site in Beijing during summer 2005. Tagged CO simulation
results suggest that regional emissions make significant
contributions to elevated CO levels over Beijing on polluted
days and that the southeastward moving cyclones bringing
northwest winds to Beijing are the key meteorological mechanisms
responsible for dispersion of pollution over Beijing in
summer. Overall CO fluxes to the NW Pacific from Asia are
found to decrease by a factor of 3–4 from spring to summer.
Much of the seasonal change is driven by decreasing
fluxes from India and Southeast Asia in summer, while
fluxes from East China are only 30% lower in summer than in
spring. Compared to spring, summertime outflow from Chinese
source regions is strongest at higher latitudes (north of
35 N). The deeper convection in summer transporting CO
to higher altitudes where export is more efficient is largely
responsible for enhanced export in summer.