华北大气本底微量气体与颗粒物的长期变化

Long-Term Variation of Trace Gases and Particulate Matter at an Atmospheric Background Station in North China

摘要: 2005年5月22日~2015年1月31日，在中国科学院大气本底观测网兴隆站开展了对微量气体(NO_x、SO₂、O₃)、颗粒物(PM_2.5)的连续观测，获得了它们的长期变化特征。近10年，兴隆大气中气体和颗粒物(NO_x、SO₂、O₃、PM2.5)的浓度表现出明显的月、季节、年际变化特征；NO₂和SO₂浓度表现出下降的趋势，它们的年减少率分别为3.37%、0.78%。但是，近10年来O₃却表现出增长的趋势，其年增长率为1.71%；在2009~2014年，PM_2.5也表现出增长趋势，其年增长率为0.91%。兴隆气体、颗粒物、能见度的变化特征揭示了大气中气液固相物质经化学和光化学过程生成高浓度O₃和细颗粒物PM_2.5的机制。根据对测量数据的综合分析，控制北京以及华北大气污染应该考虑：1) 首要控制各类人为挥发性有机物的源排放，2) 其次，继续加大控制各类NO_x和SO₂的源排放。从而减少参与大气光化学反应的反应物以及由光化学过程产生的二次污染物(O₃和PM_2.5)的生成。PM_2.5与O₃ × NO₂ × SO₂月均值之间表现出有较好的一致性，这表明控制各类污染物(包括一次和二次污染物)对于控制颗粒物PM_2.5的产生来说都是必不可少的，而且还要考虑同步控制O₃光化学污染。

Abstract: From 22 May, 2005 to 31 January, 2015, measurements of trace gases (NO_x, SO₂ and O₃) and parti-culate meter (PM_2.5) at Xionglong station, an atmospheric background observation network of Chinese Academy of Sciences were carried out. Long-term variations of NO_x、SO₂、O₃ and PM_2.5 were obtained. During recent 10 years, NO_x、SO₂、O₃ and PM_2.5 displayed evident monthly, seasonal, and annual variations generally; NO_x and SO₂ showed decrease trends at the rate of 3.37% and 0.78% per year, respectively; but, O₃ displayed an increase trend at the rate of 1.71% per year and PM_2.5 also indicated an increase trend at the rate of 0.91% per year during 2009-2014. The variations of gases, partculate mater PM_2.5 and visibility at Xinglong revealed a mechanism that high concen-trations of O₃ and particulate matter were produced by gases, liquids and particles (GLPs) in the chemical and photochemical reactions. On the basis of analyzing gases and particulate matter, in controlling air pollution in Beijing and North China, we should consider 1) to control all source emissions of anthropogenic volatile organic compounds primarily, 2) to step up efforts in controlling all source emissions of NO_x and SO₂, so as to decrease the reactants taking part in the chemical and photochemical reactions in the atmosphere and the formation of secondary pollutants, e.g., O₃ and PM_2.5. There were similar variations between monthly PM_2.5 and O₃ × NO₂ × SO₂, indicating that it is essential to control the emissions of all pollutants (including primary and secondary pollutants) in controlling PM_2.5 pollution. Therefore, it is suggested that O₃ photochemical pollution should be considered synchronously.