edu.ucar.opensky::articles:6312 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T15:15:54.119422 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7tm7b85 Study of ozone "weekend effect" in Shanghai 2008-09-01T00:00:00Z publication https://n2t.org/ark:/85065/d7tm7b85 https://doi.org/10.1007/s11430-008-0088-2 Tang, W. author Zhao, C. author Geng, F. author Peng, L. author Zhou, G. author Gao, W. author Xu, J. author Tie, Xue X. author UCAR/NCAR - Library publisher Analysis of observed ozone data in 2006 from five monitoring sites (Xujiahui, Chongming, Baoshan, Pudong, Jinshan) in Shanghai reveals that ozone (O₃) concentrations in Xujiahui are higher at weekends than those on weekdays, despite the fact that emissions of ozone precursor substances, such as oxides of nitrogen (NOx ), carbon monoxide (CO) and volatile organic compounds (VOCs) are lower at weekends than those on weekdays. The possible chemical cause of ozone "weekend effect" is that NO₃/NO ratio increases at weekends by 25.61% compared with those on weekdays. In addition, because of an average 12.13% reduction in NOx (NO + NO₃) in the early morning (05:00-09:00) at weekends compared with that on weekdays, the ozone inhibition period ends 0.5 h earlier at weekends resulting in the longer duration of ozone accumulation and the higher ozone production rate. The rate of ozone production is a function of VOCs and NOx in the atmosphere. VOCs/NOx ratio in Xujiahui is 4.55 at weekends, and 4.37 on weekdays, belonging to the "NOx -limited". The increasing VOCs/NOx ratio at weekends leads to ozone enhancement from 73 ppbv to 80 ppbv, which are consistent with ozone "weekend effect" in Xujiahui. Furthermore, combining with MICAPS cloud amount data, the fact that ozone "weekend effect" in Xujiahui weakens gradually along with the increasing of cloud amount indicates that ozone photochemical production leads to ozone "weekend effect" in Xujiahui of Shanghai. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication An edited version of this paper was published by Springer. Copyright 2008, Science in China Press and Springer. None eng geoscientificInformation