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Shan W.,Hebei University | Zhang J.,Shanghai JiaoTong University | Huang Z.,Jinshan Environmental Protection Monitoring Station | You L.,Jinshan Environmental Protection Monitoring Station
Atmospheric Research | Year: 2010

In this study, some distinct characteristics of surface ozone and related compound (NO, NO 2, and CO) levels during maritime winds (MW) and continental winds (CW) at a coastal site in the Yangtze Delta, nearby Shanghai, were presented and discussed. The frequency of MW was higher in spring and summer and lower in autumn and winter. The ozone level during MW was much higher than those during CW in each season, while the primary pollutant levels presented the opposite result. There may be ozone depression processes during CW at the site caused by relatively fresh primary pollutants, which are transported from urban Shanghai. In contrast, pollutants during MW were more aged, so the ozone depression processes were weak and the ozone level was high. Due to the lack of fresh NO, the daily ozone maximum was lagged, and the early morning ozone minimum was obscured during MW. Ozone concentrations during CW presented evident "weekend effect", while the concentrations during MW showed obvious anti-"weekend effect". Just like in urban Shanghai, "weekend effect" during CW in the site is mainly associated with "VOCs-limited" and the change of NO 2/NO ratio. The ozone anti-"weekend effect" during MW might be associated with the high NO x concentrations in weekend, which were caused by the recirculation of the pollutants carried over in weekdays from urban areas during CW. © 2010 Elsevier B.V.

Shan W.,Hebei University | Lu H.,Agricultural University of Hebei | Huo S.,Hebei University | Huang Z.,Jinshan Environmental Protection Monitoring Station | You L.,Jinshan Environmental Protection Monitoring Station
Environmental Monitoring and Assessment | Year: 2010

A high PM10 episode observed at a coastal site nearby Shanghai during 18-19 January 2007 was analyzed in this study. The maximum hourly averaged PM10 concentrations for the 2 days were 0.58 and 0.62 mg/m3, respectively. The meteorological condition during the episode was favorable for air pollution with large-scale stagnation. There was no dispersing effect by high wind, no scavenging function by precipitation, and no diluting process by clean marine air during the episode. The trajectories for 16-19 January all came from the northern region and kept in low levels, and during the episode peak time, from the morning of 18 to the morning of 19 January, trajectories all came from the northern inland areas and had passed over the coastal region of Jiangsu province before arriving at the site. The variation of the air pollution indexes (APIs) in the cities located in the upwind direction of the site during the episode days clearly shows a process of large-scale air pollution from north to south. The liner correlation coefficient for PM10 and SO2 concentrations is 0.774 during the episode, while for PM10 and CO, it even reaches 0.995, which indicated that the high PM10 was mainly emitted from the coal burning for domestic heating in winter. Therefore, the observed episode was caused by the transport of domestic heating pollutants accumulated in the boundary layer from northern continental areas. © 2009 Springer Science+Business Media B.V.

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