2017年汾渭平原东部大气颗粒物污染特征分析

高度集中的煤炭产业和繁忙的交通运输使得汾渭平原成为全国污染最严重的地区之一.利用中国环境监测总站发布的大气环境监测资料，以统计的方法分析了2017年汾渭平原东部三门峡市、运城市、渭南市、洛阳市的颗粒物质量浓度演变特征，并与北京市开展对比分析.结果表明:①2017年汾渭平原东部颗粒物污染形势较为严峻，ρ（PM_2.5）年均值范围为61~75 μg/m3，高于北京市（58 μg/m3），ρ（PM_2.5）/ρ（PM₁₀）范围为0.47~0.57，远低于北京市的0.66，说明汾渭平原东部一次颗粒物的贡献更为显著.②与北京市相比，汾渭平原东部重污染有效时数较长，在三门峡市、运城市、渭南市和洛阳市出现PM_2.5重度及以上污染过程的时数分别占全年总时数的6.56%、8.91%、9.23%和9.10%.但由于汾渭平原东部重污染期间颗粒物质量浓度较北京市低，因此造成汾渭平原东部和北京市重度及以上污染过程中颗粒物质量浓度平均值在颗粒物质量浓度年均值中占比基本相同.③汾渭平原东部颗粒物质量浓度的周变化特征与北京市有显著区别.④重污染期间，汾渭平原东部ρ（PM_2.5）和ρ（PM₁₀）的日变化特征与ρ（SO₂）相同，均呈白天高、夜间低的特征，而北京市ρ（PM_2.5）和ρ（PM₁₀）的日变化特征与ρ（SO₂）相反，呈白天低、夜间高的特征，说明汾渭平原东部特殊的能源结构、边界层动力演变和局地环流造成高架点源对重污染期间污染物质量浓度的影响较显著.研究显示，汾渭平原东部应该加强重污染期间高架点源的管控. 

Analysis of Atmospheric Particulates in the Eastern Fenwei Plain in 2017

The highly centralized coal industry and busy traffics make the Fenwei Plain one of the most polluted areas in China. Based on the atmospheric environmental monitoring data released by China Environmental Monitoring Station, the evolution characteristics of particulates in Sanmenxia City, Yuncheng City, Weinan City and Luoyang City in the eastern Fenwei Plain in 2017 were analyzed by statistical method and compared with those in Beijing. The results showed that:(1) In 2017, the pollution situation of particulates in the eastern Fenwei Plain were severe, and the annual average concentrations of PM_2.5 reached 61-75 μg/m3, which was higher than 58 μg/m3 in Beijing. The ρ(PM_2.5)/ρ(PM₁₀) was 0.47-0.57, which was much lower than 0.66 in Beijing. This indicated that contribution of primary particulates was more significant in the Fenwei Plain. (2) Compared with Beijing, the effective hours of heavy pollution in the eastern Fenwei Plain were longer. The hours of heavy pollution events accounted for 6.56%, 8.91%, 9.23% and 9.10% of the total hours in Sanmenxia City, Yuncheng City, Weinan City and Luoyang City, respectively. Because the particulates concentration in the eastern Fenwei Plain was slightly lower than that in Beijing during the period of heavy pollution, the contribution ratio of pollutant concentration of heavy pollution to the annual concentration in the eastern Fenwei Plain and Beijing were basically similar. (3) The weekly variation characteristics of particulates concentration in the eastern Fenwei Plain were significantly different from those in Beijing. (4) During the period of heavy pollution, the diurnal variations of SO₂, PM_2.5 and PM₁₀ in the eastern Fenwei Plain were consistent, showing a cycle of daytime-maximum and nighttime minimum. This was obviously different from Beijing, in which high particulates appeared at night and low concentrations appeared in daytime in Beijing. The special energy structure, the dynamic evolution of boundary layer and the local circulation caused the elevated pollution sources to have a significant influence on the mass concentration of pollutants during the period of heavy pollution in the eastern Fenwei Plain. (5) Some targeted air quality control strategies in the eastern Fenwei Plain were suggested to be taken according to its own characteristics. The research showed that the control of elevated pollution sources should be strengthened in the Eastern Fenwei Plain during the period of heavy pollution.