Dong Zhe, Yuan Ming-Hao, Su Fang-Cheng, Zhang Jian-Fei, Sun Jia-Bin, Zhang Rui-Qin
College of Chemistry, Zhengzhou University, Zhengzhou 450001, China.
Zhengzhou Environmental Protection Monitoring Center Station, Zhengzhou 450007, China.
Huan Jing Ke Xue. 2021 May 8;42(5):2179-2189. doi: 10.13227/j.hjkx.202009208.
To study the spatiotemporal variations in fine particulate matter (PM) and the impact of air quality management in autumn and winter in Zhengzhou, five sites were selected to collect PM samples from the autumn of 2017 to the winter of 2018, and the characteristics of the chemical components were analyzed. The positive matrix factorization (PMF) model was also applied to identify the sources of PM, and the effect of air quality control was evaluated to provide support for air quality control in autumn and winter in the next stage. The PM concentrations in the four seasons in Zhengzhou were ranked as winter > autumn > spring > summer. The PM concentration at Zhengzhou University (ZZU) was the highest (8.7% higher than the average concentration), and the PM concentrations at the other sites were slightly lower than the average concentration. The concentration of water-soluble ions (WSIs) was low in spring and summer and high in autumn and winter. The average proportions of SO, NO, and NH in the nine WSIs were as high as 22.5%, 43.6%, and 23.4%, respectively. The proportion of Cl in winter was higher than that in the other seasons owing to coal combustion (6.7% and 6.6% in 2017 and 2018, respectively). Owing to wind and sand, the proportions of Ca and Mg in spring were the highest (4.4% and 0.4%, respectively), and those at the Jiancezhan (JCZ) and ZZU sites were higher than those at the other sites. K, as a marker of biomass burning, had a higher proportion in spring, autumn, and winter. The proportion of K in the spring of 2018 was 1.9%, those in the autumn and winter of 2017 were 1.6% and 2.1%, respectively, and those in the autumn and winter of 2018 were 1.3% and 1.8%, respectively. JCZ, Hangkonggang (HKG), and Xinmi (XM) had higher proportions of NO, and the proportions of SO were lower. Secondary organic carbon (SOC) pollution was serious in autumn and winter, and the concentration accounted for more than half of the organic carbon (OC). In 2018, the SOC/OC at the JCZ and ZZU sites decreased compared with that in 2017, but that at the other three sites increased significantly, thereby indicating that different air pollutant emissions in these regions had different performances in response to control policies. The chemical composition reconstruction results showed that the proportion of sulfate was highest in summer (25.0%), the contribution of nitrate was higher in autumn (23.1% and 25.1% for 2017 and 2018, respectively) and winter (20.6% and 23.0% for 2017 and 2018, respectively), the proportion of crustal material was higher in spring (18.2%), and the contribution of secondary organic aerosol (SOA) was the highest in winter (14.1% and 20.5% for 2017 and 2018, respectively). SOA had higher contributions at the JCZ and HKG sites (16.9% and 16.4%, respectively), and ZZU was affected more by primary organic aerosol (14.3%) and crustal materials (12.1%). The PMF results showed that secondary inorganic salts (37.5%), SOA (15.4%), traffic (14.9%), industry (4.8%), coal combustion (16.0%), fugitive dust (6.5%), and biomass burning (2.8%) were the main pollution sources of PM in Zhengzhou. SOA and coal combustion contributed more in winter and fugitive dust contributed more in spring, followed by autumn. Biomass burning contributed more in spring and autumn. The urban sites JCZ and ZZU and the characteristic site HKG near the airport were more affected by traffic sources (16.9%, 16.2%, and 16.0%, respectively) than the other sites. The impact of biomass burning on the non-urban sites XM and HKG was slightly larger (both 2.7%), and the contribution of coal combustion to the suburban site XM was higher (16.8%). Owing to the construction around ZZU, the loading of fugitive dust at ZZU was higher than that at other sites. Comparing the results of the two-year autumn and winter, the contribution of SOA, traffic, and industry increased in the autumn and winter of 2018, whereas the contribution of secondary inorganic salts, coal combustion, and biomass burning decreased and the contribution of fugitive dust in winter also decreased. The results showed that the control strategies in autumn and winter had significant effects on the primary sources, including fugitive dust, coal combustion, and industry, and SOA precursor volatile organic compounds should be targeted for further pollution control.
为研究郑州市秋冬季细颗粒物(PM)的时空变化及空气质量管控的影响,选取5个站点于2017年秋季至2018年冬季采集PM样本,并分析其化学成分特征。还应用正定矩阵因子分解(PMF)模型识别PM的来源,评估空气质量管控效果,为下一阶段郑州市秋冬季空气质量管控提供支撑。郑州市四季PM浓度排序为冬季>秋季>春季>夏季。郑州大学(ZZU)的PM浓度最高(比平均浓度高8.7%),其他站点的PM浓度略低于平均浓度。水溶性离子(WSIs)浓度在春季和夏季较低,在秋季和冬季较高。9种WSIs中SO、NO和NH的平均占比分别高达22.5%、43.6%和23.4%。冬季Cl的占比高于其他季节,这归因于煤炭燃烧(2017年和2018年分别为6.7%和6.6%)。由于风沙影响,春季Ca和Mg的占比最高(分别为4.4%和0.4%),监测站(JCZ)和ZZU站点的占比高于其他站点。K作为生物质燃烧的标志物,在春季、秋季和冬季占比更高。2018年春季K的占比为1.9%,2017年秋季和冬季分别为1.6%和2.1%,2018年秋季和冬季分别为1.3%和1.8%。JCZ、航空港区(HKG)和新密(XM)的NO占比更高,SO占比更低。秋冬季节二次有机碳(SOC)污染严重,其浓度占有机碳(OC)的一半以上。2018年,JCZ和ZZU站点的SOC/OC与2017年相比有所下降,但其他三个站点显著上升,这表明这些地区不同的空气污染物排放对管控政策的响应表现不同。化学成分重构结果显示,夏季硫酸盐占比最高(25.0%),秋季硝酸盐贡献更高(2017年和2018年分别为23.1%和25.1%),冬季(2017年和2018年分别为20.6%和23.0%),春季地壳物质占比更高(18.2%),冬季二次有机气溶胶(SOA)贡献最高(2017年和2018年分别为14.1%和20.5%)。SOA在JCZ和HKG站点贡献更高(分别为16.9%和16.4%),ZZU受一次有机气溶胶(14.3%)和地壳物质(12.1%)影响更大。PMF结果表明,二次无机盐(37.5%)、SOA(15.4%)、交通源(14.9%)、工业源(4.8%)、煤炭燃烧(16.0%)、扬尘(6.5%)和生物质燃烧(2.8%)是郑州市PM的主要污染源。SOA和煤炭燃烧在冬季贡献更大,扬尘在春季贡献更大,其次是秋季。生物质燃烧在春季和秋季贡献更大。城市站点JCZ和ZZU以及机场附近的特征站点HKG比其他站点受交通源影响更大(分别为16.9%、16.2%和16.0%)。生物质燃烧对非城市站点XM和HKG的影响略大(均为2.7%),煤炭燃烧对郊区站点XM的贡献更高(16.8%)。由于ZZU周边建设,ZZU的扬尘负荷高于其他站点。比较两年秋冬季的结果,2018年秋冬季SOA、交通源和工业源的贡献增加,而二次无机盐、煤炭燃烧和生物质燃烧的贡献下降,冬季扬尘贡献也下降。结果表明,秋冬季管控策略对扬尘、煤炭燃烧和工业源等主要污染源有显著影响,应针对SOA前体挥发性有机化合物进行进一步污染控制。