Residence time analysis of photochemical buildup of ozone in central eastern China from surface observation at Mt. Tai, Mt. Hua, and Mt. Huang in 2004.

Using data from surface observation, backward trajectories, and residence time analysis, the amounts of regional photochemical ozone buildup due to the large-scale anthropogenic sources in central eastern China (CEC, 30.5-40.5 N, 112.5-122.5 E) at Mt. Tai, Mt. Hua, and Mt. Huang in 2004 were quantified. It was found that the CEC anthropogenic sources influenced the air masses and the associated ozone production most at Mt. Tai, located at the center of CEC domain. At Mt. Hua to the west of CEC domain and at Mt. Huang to the south of CEC domain, the air masses and the associated ozone production showed less CEC anthropogenic influences on a regional scale. At Mt. Tai and Mt. Huang, the ozone mixing ratios in the air masses that passed over polluted source regions in CEC increased during the first 40-70 h after arrival and showed the highest production rate of 31.2 and 12.2 ppb/day, respectively, in May and June. It was estimated that the CEC anthropogenic sources contributed 34-42% of ozone at Mt. Tai and 8-14% at Mt. Huang during this ozone peak season. The large contributions from CEC sources during fall season (Sep-Nov) were also estimated as 31-44 and 17-23% but with the lower ozone production rate of 22.6 and 8.4 ppb/day, respectively, for Mt. Tai and Mt. Huang.