Vertical ozone characteristics in urban boundary layer in Beijing.

Zhiqiang Ma, Honghui Xu, Wei Meng, Xiaoling Zhang, Jing Xu, Quan Liu, Yuesi Wang

Environmental monitoring and assessment 2013 Jul

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Vertical ozone and meteorological parameters were measured by tethered balloon in the boundary layer in the summer of 2009 in Beijing, China. A total of 77 tethersonde soundings were taken during the 27-day campaign. The surface ozone concentrations measured by ozonesondes and TEI 49C showed good agreement, albeit with temporal difference between the two instruments. Two case studies of nocturnal secondary ozone maxima are discussed in detail. The development of the low-level jet played a critical role leading to the observed ozone peak concentrations in nocturnal boundary layer (NBL). The maximum of surface ozone was 161.7 ppbv during the campaign, which could be attributed to abundant precursors storage near surface layer at nighttime. Vertical distribution of ozone was also measured utilizing conventional continuous analyzers on 325-m meteorological observation tower. The results showed the NBL height was between 47 and 280 m, which were consistent with the balloon data. Southerly air flow could bring ozone-rich air to Beijing, and the ozone concentrations exceeded the China's hourly ozone standard (approximately 100 ppb) above 600 m for more than 12 h.

Citation

Zhiqiang Ma, Honghui Xu, Wei Meng, Xiaoling Zhang, Jing Xu, Quan Liu, Yuesi Wang. Vertical ozone characteristics in urban boundary layer in Beijing. Environmental monitoring and assessment. 2013 Jul;185(7):5449-60