兰州市高分辨率人为源排放清单建立及在WRF-Chem中应用评估

Establishment of a High-resolution Anthropogenic Emission Inventory and Its Evaluation Using the WRF-Chem Model for Lanzhou

城市尺度高分辨率人为源大气污染物排放清单是城市空气质量预报预警、污染成因分析和减排措施制定的重要基础数据,目前我国西部地区城市尺度的人为源排放清单研究仍然相对薄弱,能对接于空气质量模式的排放清单更为缺乏.本文整合已发表的清单文献,建立了可对接于空气质量模式的2016年兰州市城市尺度的人为源清单模型(HEI-LZ16),将之应用于WRF-Chem模式,评估HEI-LZ16的准确性和适用性.结果表明:兰州市2016年人为源排放的SO_(2)、NO_(x)、CO、NH_(3)、VOCs、PM_(10)、PM_(2.5)、BC和OC总量分别为25642、53998、319003、10475、35289、49250、19822、2476和1482 t·a^(-1).在模拟时间内,HEI-LZ16相比于MEIC,O_(3)和PM_(2.5)的NME值分别减小了140.2%和28.8%,HEI-LZ16更加准确适用.分析了HEI-LZ16情景下模拟的PM_(2.5)和O_(3)时空分布,兰州市臭氧MDA8呈现冬春季城区低而郊区高,夏秋季河谷城区西部及其下风向地区高的分布特征,夏秋季高浓度区的分布受偏东风和光化学反应的共同影响,冬季城区O_(3)浓度受NO_(x)排放的抑制作用浓度反而降低.PM_(2.5)浓度的高值区主要集中在黄河河谷盆地,本研究表明沿白银—兰州黄河河谷盆地走向的西侧存在一个污染物传输通道,其对兰州市环境空气质量具有较大的影响.

City-scale high-resolution anthropogenic emission inventories are an important tool for ambient air quality forecasting and early warning,the analysis of underlying causes,and policy making.At present,city-scale anthropogenic emissions inventories for use in air quality models are scarce for West China.By studying the literature on emission inventories,this paper establishes a city-scale anthropogenic emission inventory for Lanzhou(HEI-LZ16)as the basis for an air quality model.The weather research and forecasting with chemistry(WRF-Chem)model was used to evaluate the applicability of the emission inventory at different resolutions in Lanzhou.The results showed that the emission amounts of SO_(2),NO_(x),CO,NH_(3),VOCs,PM_(10),PM_(2.5),BC,and OC in Lanzhou were 25642,53998,319003,10475,35289,49250,19822,2476,and 1482 t·a^(-1)in 2016,respectively.Compared with the simulation scenario of multi-resolution emission inventory for China(MEIC),normalized mean error(NME)of O_(3)and PM_(2.5)under the HEI-LZ16scenario decreased by 140.2%and 28.8%,respectively.The HEI-LZ16 inventory is more suitable for application in air pollution research in Lanzhou,which was verified by the WRF-Chem model and the observational data.The spatiotemporal distributions of PM_(2.5)and O_(3)were also analyzed using the HEI-LZ16 scenario.The ozone concentration of the maximum daily 8-h average(MDA8)in Lanzhou was low in urban areas and high in the suburbs during winter and spring,and high in the west of the urban valley and its downwind areas during summer and autumn.MDA8 in summer and autumn was influenced by easterly winds and photochemical reactions.In winter,ozone concentrations in urban areas are suppressed by NO_(x)emissions but the concentration decreases.High PM_(2.5)concentrations are mainly concentrated within the Yellow River Valley.This study shows that there is a pollutant transmission channel along the western side of the Baiyin-Lanzhou Yellow River Valley,which has a greater impact on the ambient air quality in Lanzhou.