Abstract: The Community Multi-Scale Air Quality (CMAQ) modeling system was applied to simulate the meteorology field, O₃ and PM10 in the Pearl River Delta (PRD) region in the autumn of 2008, in order to elucidate the impact of the typical meteorological conditions on the O₃ and PM10 pollution episodes. It was found that PRD pollution characteristics presents periodic variation affected by cold air processes in the autumn of 2008. In general, good air quality was presented when cold air passing through while serious pollution was took place before and after the cold air invasion. 1) Before the cold air invasion, when the weather system “cold front front part” was presented, the height of the mixing layer was often low due to a presence of temperature inversion. Therefore, the PM10 emitted or formed at night was continuously accumulated in the morning hours causing the air pollution in northern and central PRD; the afterwards transport of the O₃ during daytime and PM10 during nighttime with northern wind would cause the air pollution in southern PRD. 2) Before the cold air invasion, when the weather system “high-pressured base” was presented, an inversion layer was built up to prevent vertical mixing; both O₃ and PM10 was then mainly horizontally transported with northeasterly wind; consequently forming air pollution in southwestern PRD. 3) After the cold air invasion, under the control of a ridge high pressure type of weather condition, temperature inversion was built up near the surface and a stagnant condition was presented; thus, O₃ and PM10 was trapped in the source regions such as western, northwestern and central PRD, resulted in serious local pollutions.

Key words: Pearl River Delta (PRD), O₃, PM10, meteorological conditions

摘要： 利用化学传输模式(CMAQ)系统对珠江三角洲(珠三角)地区2008年秋季的气象场、O₃和PM10的污染状况进行模拟, 研究典型气象条件对O₃和PM10污染的影响。结果表明2008年秋季珠三角受冷空气过程影响, 污染特征具有周期性, 冷空气过境期间空气质量良好, 冷空气过境前期和回暖期污染严重。1) 过境前期如处于冷锋前部型天气控制下, 珠三角近地面形成逆温层, 混合层高度较低, 早晨累积前日夜间生成的PM10, 造成珠三角北部和中部污染; O₃日间和PM10夜间污染区域分布在偏北风的下风向, 造成珠三角南部污染。2) 过境前期如处于高压底部型天气控制下, 将形成逆温层, 垂直输送较差, O₃和PM10沿着东北风向水平传输, 造成珠三角西南部污染。3) 回暖期通常处于变性高压脊型天气控制下, 珠三角近地面形成逆温层, 受静小风影响, 水平输送较差, 导致O₃和PM10的污染分布在珠三角西部、西北部和中部源排放区, 造成持续性局地污染。

关键词: 珠江三角洲(珠三角), O₃, PM10, 污染气象条件