中国典型城市O3与前体物变化特征及相关性研究

为了解我国不同气候背景城市O₃污染及其与前体物的关系，选取北京市、沈阳市、银川市、成都市、南京市和广州市作为典型代表城市，基于这6个城市2014-2016年ρ（O₃）、ρ（NO₂）和ρ（CO）资料对O₃与其前体物质量浓度变化特征及二者相关性进行研究.结果表明:①2014-2016年6个城市ρ（O₃）年均值大小顺序依次为南京市>沈阳市>北京市>银川市>成都市>广州市，ρ（NO₂）年均值大小顺序依次为北京市>成都市>南京市>沈阳市>广州市>银川市，ρ（CO）年均值大小顺序依次为北京市>银川市>成都市>沈阳市>南京市>广州市.2014-2016年除广州市ρ（O₃）下降、沈阳市变化不明显外，其他城市ρ（O₃）总体呈上升趋势；各城市ρ（NO₂）和ρ（CO）普遍呈下降趋势.②广州市ρ（O₃）夏季最高、春季最低，其他城市四季ρ（O₃）大小顺序依次为夏季>春季>秋季>冬季；北京市、沈阳市和银川市四季ρ（NO₂）和ρ（CO）大小顺序依次为冬季>秋季>春季>夏季，成都市、广州市和南京市为冬季>春季>秋季>夏季.各城市ρ（O₃）和ρ（O_x）日变化呈单峰型，ρ（NO₂）和ρ（CO）日变化呈双峰型.③6个城市城区ρ（O₃）均低于清洁对照点，城区ρ（NO₂）和ρ（CO）均高于清洁对照点，并且城区与清洁对照点O₃及其前体物质量浓度差值随城市和月份变化存在一定的差异.④各城市ρ（O₃）与ρ（NO₂）和ρ（CO）均呈负相关，与ρ（O_x）呈显著正相关；城区ρ（O₃）与ρ（NO₂）和ρ（CO）的相关性均好于清洁对照点，清洁对照点ρ（O₃）与ρ（O_x）的相关性则好于城区.⑤各城市ρ（O₃）超标率随ρ（NO₂）和ρ（CO）的增加均呈先迅速上升再快速减小，之后缓慢变化的特征，但ρ（O₃）超标率峰值对应的ρ（NO₂）和ρ（CO）有所差异.研究显示，日照条件较好的银川市、北京市和沈阳市O₃与其前体物相关性较成都市、南京市和广州市强. 

Characteristics and Correlation of Ozone and Its Precursors in Typical Cities in China

In order to understand the O₃ pollution and its relationship with precursors in different climate background cities in China, the representative cities of Beijing, Shenyang, Yinchuan, Chengdu, Nanjing and Guangzhou were selected, and based on the concentrations of ozone and its precursors observed in these six cities from 2014 to 2016, the characteristics and its relationship with precursors in typical cities were analyzed. The results showed that the order of annual average O₃ concentration from high to low was Nanjing City, Shenyang City, Beijing, Yinchuan City, Chengdu City and Guangzhou City, while the order of NO₂ was Beijing, Chengdu City, Nanjing City, Shenyang City, Guangzhou City and Yinchuan City, and CO was in the order of Beijing, Yinchuan City, Chengdu City, Shenyang City, Nanjing City and Guangzhou City. In these three years, except for the decrease of O₃ concentration in Guangzhou City and there was no significant O₃ change in Shenyang City. The ozone concentrations in other cities were generally increasing, while the NO₂ and CO in all cities were generally decreasing. The O₃ concentration in Guangzhou City was the highest in summer and the lowest in spring, but the other cities were the highest in summer, and the lowest in winter. NO₂ and CO concentrations from high to low in Beijing, Shenyang City and Yinchuan City were winter, autumn, spring and summer, while those in Chengdu City, Guangzhou City and Nanjing City were winter, spring, autumn and summer. The daily variation of O₃ and O_x in all cities showed a single peak pattern, while NO₂ and CO exhibited a double peak pattern. In all typical cities, the concentration of O₃ in urban areas was lower than that in clean control point, while the concentration of NO₂ and CO in urban areas was higher than that in clean control point. The difference of O₃ concentration and its precursor concentration between urban area and clean control point varied with the city and time. O₃ was negatively correlated with NO₂ and CO in all cities, while positively correlated with O_x. The correlation between O₃ and CO and NO₂ in urban area was better than that in clean control points for all cities, while the correlation between O₃ and O_x in clean control points was better than that in urban areas. The over-standard rate of ozone in all cities generally increased rapidly first, then decreased rapidly, and then changed slowly with the increase of NO₂ and CO concentrations. However, the NO₂ and CO concentrations corresponding to the peak of ozone over-standard were different for different cities. The studies showed that the correlation between O₃ and its precursors was stronger in Yinchuan City, Beijing and Shenyang City with better sunshine conditions than in Chengdu City, Nanjing City and Guangzhou City.