Suchergebnisse

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 3 , CO, NO y , and SO 2 during August 2008, relative to August 2006–2007. The mean daytime mixing ratio of O 3 was lower by about 15 ppbv, reduced to 50 ppbv, in August 2008. The relative reductions in daytime SO 2 , CO, and NO y were 61%, 25%, and 21%, respectively. Changes in SO 2 and in species correlations from 2007 to 2008 indicate that emissions of SO 2 , CO, and NO x 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 3 during August 2008, accounting for 80% of the O 3 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 3 far beyond the Beijing urban area, resulting in reductions in boundary layer O 3 of 2–10 ppbv over a large region of the North China Plain and Northeastern China.

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 2006–2007. 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.