黄河流域七大城市群污染气体时空变化特征卫星遥感监测

Spatio-temporal characteristics of air pollutants in major urban agglomerations of the Yellow River Basin

为探究黄河流域大气污染的时空演变特征,本文从城市群角度出发,选取HCHO、NO_(2)及SO_(2)为诊断指标,对比分析2005—2019年七大城市群OMI观测对流层HCHO、NO_(2)及边界层SO_(2)柱浓度的年、季、月变化。研究揭示,流域内:(1)HCHO、NO_(2)及SO_(2)柱浓度高值区均集中在山东半岛城市群、中原城市群、晋中城市群南部和关中平原城市群东部。(2)HCHO柱浓度在2005—2019年呈波动上升趋势,七大城市群的月变化均呈单峰结构,且夏季高、冬季低、春季和秋季相当。(3)NO_(2)柱浓度在2005—2011年呈上升趋势,仅2008年出现短暂小幅下降。2011年执行《火电厂大气污染物排放标准》(GB 13223—2011)后,呼包鄂榆、宁夏沿黄和晋中城市群开始大幅下降,山东半岛(2012年有小幅下降)、中原和关中平原城市群则在2013年《大气污染防治行动计划》实施后才开始大幅下降。月变化呈开口向上抛物线形态,浓度越高单峰结构越明显,且冬季高、夏季低、春季和秋季相当。(4)SO_(2)柱浓度在2007年达到顶峰,2008年开始大幅下降,2010年后呈波动下降趋势,月变化、季变化均与NO_(2)相似。黄河流域上游的兰西和宁夏沿黄城市群、上中游交界处的呼包鄂榆城市群空气质量较好,中游的关中平原和晋中城市群次之,中下游交界处的中原城市群和下游山东半岛城市群则较差。

To explore air pollutants’ temporal and spatial evolution characteristics in the Yellow River Basin, we analyze the annual, seasonal, and monthly changes of the concentrations of OMI HCHO, NO_(2) , and SO_(2) in seven major urban agglomerations from 2005 to 2019. High concentration areas of the three pollutants concentrated in Shandong Peninsula Urban Agglomeration(SPUA), Zhongyuan Urban Agglomeration(ZYUA), the southern part of Jinzhong Urban Agglomeration(JZUA), and eastern part of Guanzhong Plain Urban Agglomeration(GPUA). The HCHO column troposphere concentration showes a fluctuating upward trend from 2005 to 2019 in seven urban agglomerations. Its monthly variation showes a single peak structure, high in summer, low in winter, and much the same in spring and autumn. The NO_(2) troposphere column concentration showes an upward trend from 2005 to 2011 and only slightly decreased in 2008. It begins to decline significantly in the Hubao-Eyu Urban Agglomeration(HEUA), Ningxia along the Yellow River Urban Agglomeration(NYUA), and JZUA from 2011 due to the implementation of the Emission Standard of Air Pollutants for Thermal Power Plants(GB 13223—2011), while SPUA(with a slight decrease in 2012), ZYUA, and GPUA due to the Air Pollution Prevention and Control Action Plan from 2013. Its monthly variation of the seven urban agglomerations showes an upward parabola where the higher the concentration, the more pronounced the unimodal structure, high in winter, low in summer, and much the same in spring and autumn. The SO_(2) column concentration reaches the peak in 2007, begins to decline sharply in 2008, and showes a fluctuating downward trend after 2010. Its monthly and seasonal variations are similar to that of NO_(2) . The air quality of Lanzhou-Xining Urban Agglomeration, NYUA in the upper reaches of the Yellow River Basin, and HEUA at the junction of upper and middle reaches are better than the GPUA and JZUA in the middle reaches. The air quality of ZYUA at the intersection of the middle and lower reaches and SPUA at the lower reaches is inferior.