大连市区PM2.5污染现状及影响因素分析

2013年大连市区空气中PM2.5年均值为52μg/m^3,超出国家二级标准0.49倍.大连PM2.5的污染一是受本地以及区域性冬季燃煤的影响,各项污染物在这一时期集中排放,强度过大,特别是采暖季节外来输送的贡献较大;二是由于不利的气象条件,近地面风速小,大气层结稳定,使污染物易形成积聚效应、难以及时扩散,特别是在西南风向时污染比较严重;三是受机动车尾气排放的影响.

Analysis on Status and Influential Factors on the PM2.5 Pollution in Dalian

In 2013, the annual average concentration of PM2.5 is 52μg/m^3 in Dalian city, which exceed the National Ambient Air Quality Standard Ⅱ 0. 49 times. The influential factors include three paris. The first, it is affected by the local and regional coal combustion in winter, various pollutants are emitted into the atmosphere concentratively and the intensity is too large in this period, especially the great contribution of the outside transport in heating season. The second, the meteorological conditions are adverse. The pollutants are easy to form the accumulation effect and hardly diffused in time when the speed of the surface wind is low and the atmosphere structure is stable. In particular, the southwest wind increases this situation. The last, it is ＇affected by vehicle emissions.