Environmental Chemical Processes Laboratory, Department of Chemistry, University of Crete, Voutes Campus, 71003, Heraklion, Greece.
Sci Total Environ. 2013 Jan 15;443:920-31. doi: 10.1016/j.scitotenv.2012.11.048. Epub 2012 Dec 17.
Ozone (O(3)) mixing ratios were measured at three different sites (urban/traffic, semi-rural and rural/island) in Istanbul from September 2007 to December 2009 in order to determine the diurnal, monthly and seasonal variations of O(3) and nitrogen oxides (NO(x)) and to study the local and regional impacts. This is the first study that evaluates the O(3) levels in semi-rural and rural sites in Istanbul in addition to the urban sites. The diurnal O(3) variations are generally characterized by afternoon maxima (64 ppb at the urban, 80 ppb at the semi-rural and 100 ppb at the rural site) and the nighttime minimum being more pronounced at the polluted urban site. The monthly mean O(3) mixing ratios start to increase in March, reaching their maximum values in August for the urban (~25 ppb) and semi-rural sites (30 ppb). However, at the rural site, the monthly mean O(3) levels reach their maximum value in June (35 ppb). The O(3) mixing ratios for weekends were higher than those on weekdays at each site by up to 28%, possibly due to changes in VOC sensitivity and reduction in NO(x) levels. In order to better understand and characterize the relationship between air masses and O(3) levels, cluster analysis was applied to the back-trajectories calculated by the HYSPLIT model for the semi-rural site. The analyses clearly showed that major transport is characterized by northern and western clusters, particularly from the Eastern Europe and the Mediterranean region, as well as recirculation over Istanbul due to high pressure systems leading to accumulated levels of O(3). The results clearly suggest that extended measurement networks from urban to rural sites should be considered for a more comprehensive evaluation of O(3) levels.
臭氧 (O(3)) 混合比在伊斯坦布尔三个不同地点（城市/交通、半农村和农村/岛屿）进行了测量，时间从 2007 年 9 月到 2009 年 12 月，目的是确定臭氧和氮氧化物 (NO(x)) 的日变化、月变化和季节变化，并研究当地和区域影响。这是首次评估伊斯坦布尔半农村和农村地区臭氧水平的研究，此外还评估了城市地区的臭氧水平。臭氧的日变化一般以午后最大值为特征（城市地区为 64ppb，半农村地区为 80ppb，农村地区为 100ppb），污染严重的城市地区夜间最小值更为明显。臭氧混合比的月平均值从 3 月开始增加，到 8 月达到最大值，城市（约 25ppb）和半农村（30ppb）站点达到最大值。然而，在农村地区，6 月（35ppb）达到月平均臭氧水平的最大值。每个站点的周末臭氧混合比都比工作日高，最高可达 28%，这可能是由于 VOC 敏感性的变化和 NO(x)水平的降低。为了更好地理解和描述气团与臭氧水平之间的关系，对 HYSPLIT 模型计算的半农村站点的后向轨迹进行了聚类分析。分析结果清楚地表明，主要的传输特征是来自东欧和地中海地区的北部和西部气团，以及由于高压系统导致的伊斯坦布尔上空的再循环，导致臭氧积累水平升高。结果清楚地表明，应考虑从城市到农村地区的扩展测量网络，以更全面地评估臭氧水平。
