乌海市高分辨率大气污染源排放清单构建及其在臭氧污染成因探究中的应用

乌海市是我国典型的煤焦化工业基地,大气污染物排放总量较大且近年来夏季O₃污染问题逐渐突出,明确大气污染物排放特征,探究O₃污染形成机制是客观认识其O₃污染现状,科学制定污染控制措施的基础.基于"系数法"采用自下而上的方式构建了2018年乌海市高分辨率大气污染源排放清单（HEI-WH18）,利用WRF-Chem对HEI-WH18的适用性和准确性进行评估,并结合模式诊断模块探究了乌海市夏季O₃污染形成的原因.排放清单结果表明,2018年乌海市SO₂、NO_x、CO、PM₁₀、PM_2.5、VOCs、NH₃、BC和OC的排放总量分别为65943、40934、172867、159771、47469、69191、1407、1491和1648 t ·a^-1.与MEIC清单相比,利用HEI-WH18能更好地捕捉到O₃及其前体物的排放变化规律和量级,适用于乌海市夏季O₃的模拟及其来源分析研究.从O₃及前体物的空间分布来看,乌海市海勃湾城区白天为O₃高值区,3个工业园区无论白天和夜间均为O₃低值区和NO₂高值区,CO的空间分布特征与煤层及矸石堆自燃源一致.根据对O₃污染过程的诊断分析,边界层中高层O₃浓度的升高主要是平流输送和化学过程共同作用的结果,低层O₃浓度的升高是垂直混合和平流输送导致的,化学过程在低层的贡献较为复杂,其正贡献起到了维持高O₃浓度的作用,负贡献结合平流输送造成了O₃污染的最终消散.

Establishment of High-Resolution Emissions Inventory in Wuhai and Its Application in Exploring the Causes of Ozone Pollution

Wuhai is a typical coking industrial base including three industrial parks within its jurisdiction. The emission amount of air pollutants is considerable here, and O₃ pollution has become serious in recent years. Clarifying the air pollutant emission characteristics and exploring the formation mechanism of O₃ are the basis for objectively understanding the O₃ pollution and formulating scientific prevention and control measures. This study established the high-resolution emission inventory of Wuhai in 2018 (HEI-WH18) based on the "coefficient method," evaluated the applicability and accuracy of HEI-WH18 using the WRF-Chem model, and explored the causes of O₃ pollution in summer using WRF-Chem diagnosis module output. The HEI-WH18 showed that the total emissions amount of SO₂, NO_x, CO, PM₁₀, PM_2.5, VOCs, NH₃, BC, and OC were 65943, 40934, 172867, 159771, 47469, 69191, 1407, 1491, and 1648 t·a^-1, respectively. HEI-WH18 could capture the variation and magnitude of O₃ and its precursors better than the MEIC, which was suitable for the O₃ simulation and source analysis in summer. From the perspective of spatial distribution, Haibowan was a high-value area of O₃ during the daytime, and the three industrial parks were low-value areas of O₃ and high-value areas of NO₂ during the daytime and nighttime. The spatial distribution characteristics of CO were consistent with the spontaneous combustion of coal and coal gangue sources. According to the diagnostic analysis of two O₃ pollution processes, the O₃ increase in the upper boundary layer was mainly related to the advection transport and chemical process, and it was caused by vertical mixing and the advection transport process in the lower boundary layer. The contribution of the chemical process in the lower boundary layer was complicated, and its positive contribution played a role in maintaining a high O₃ concentration, whereas its negative contribution combined with advection transport resulted in the final dissipation of O₃ pollution.