内蒙古近地面臭氧污染时空分布特征及气象条件分析

使用2018—2020年内蒙古臭氧(O₃)、气象要素观测资料和NCEP FNL资料,统计分析内蒙古近地面O₃质量浓度的时空分布特征和变化趋势,并针对全区O₃污染典型个例分析其天气形势和气象要素的影响作用。结果表明:内蒙古2018—2020年O₃质量浓度年评价值呈逐年下降趋势,2020年较2018年下降10.3%,各盟市O₃超标率也显著降低,仅赤峰市和通辽市略微上升。内蒙古O₃质量浓度高值分布在中西部偏南地区,尤其是乌海市和鄂尔多斯市;O₃超标率峰值主要出现在5—7月,周末效应存在东西部差异。O₃浓度变化和天气形势关系密切,南部暖平流和暖高压控制有利于O₃生成,西北部冷平流和冷涡发展使得O₃浓度下降;高温、低湿、微风和较高的能见度均为诱发O₃污染的重要气象条件,而西北大风通过降低温度、能见度和易于扩散的风向使得内蒙古O₃浓度降低,但同时可能会导致PM₁₀污染。

Analysis of Meteorological Conditions and Temporal and Spatial Distribution Characteristics of Ground-Level Ozone Pollution in Inner Mongolia

Using the observational data of ozone and meteorological elements and NCEP FNL data in Inner Mongolia from 2018 to 2020,its temporal and spatial distribution characteristics of ground-level ozone concentration were statistically analyzed in this paper.Aiming at typical cases of ozone pollution in Inner Mongolia,the influence of weather situation and meteorological factors were analyzed.The conclusions showed that the annual evaluation value of ozone concentration in Inner Mongolia from 2018 to 2020 presented a downward trend year by year,the ozone in 2020 decreased by 10.3% compared with 2018,the ozone exceeding rate of all league cities dropped significantly,only Chifeng City and Tongliao City slightly increased.The high value area of ozone concentration was in the southern part of central and western Inner Mongolia,especially Wuhai City and Ordos City.The peak ozone excess rate occurred from May to July,and the weekend effect was different from east to west.The change of ozone concentration was closely related to the weather situation,warm advection and warm high pressure were conducive to the generation of ozone,cold advection and cold vortex reduced the ozone concentration.High temperature,low humidity,breeze and high visibility were important meteorological conditions that induced ozone pollution,while the northwest gale reduced the ozone concentration in Inner Mongolia by reducing temperature,visibility and easy-to-spread wind directions,but at the same time it may cause PM₁₀ pollution.