成都及周边地区大气污染物时空变化特征分析

Analysis of the Characteristics of the Temporal and Spatial Changes of Air Pollutants in Chengdu and Surrounding Ar-eas

摘要: 本文利用2013~2015年成都市8个空气监测站点(金泉两河、十里店、三瓦窑、沙河铺、梁家巷、草堂寺、人民公园、灵岩寺)的PM_2.5，PM₁₀，SO₂，NO₂，O₃和CO逐小时观测资料，分析各类污染物的时空分布特征，并对颗粒物的来源，时空变化原因进行了分析。研究表明：1) 2013~2015年成都市各监测点PM_2.5，PM₁₀，SO₂的年均浓度逐年显著降低。除灵岩寺外各监测点PM_2.5，PM₁₀，SO₂，NO₂和CO的月变化、季节变化趋势一致，这表明成都市污染物来源具有相似性，其中PM_2.5和PM₁₀超标严重。清洁对照点灵岩寺的PM_2.5，PM₁₀，NO₂和CO质量浓度都要低于成都市区各监测点，O₃高于市区各监测点，SO₂与市区各监测点相差不大。2) PM_2.5和PM₁₀质量浓度存在显著的空间关联，即相近监测点的PM_2.5和PM₁₀质量浓度在空间上具有相似的聚集特征。成都市及其周边地区PM_2.5和PM₁₀年均质量浓度在空间上表现为西北低、东南高，市区西北部PM_2.5和PM₁₀污染最为严重。高浓度的PM_2.5和PM₁₀在秋季显著南压，向市中心增大的趋势明显。3) 成都市大气颗粒物污染以细粒子为主。各监测点的PM_2.5/PM₁₀值季节变化规律相同，即PM_2.5/PM₁₀值冬季 > 秋季 > 夏季 > 春季。PM_2.5和PM₁₀在春季受工业燃烧等固定污染源影响较大，在秋季受机动车尾气等移动污染源影响较大。

Abstract: In this paper, the hour-by-hour observations of PM_2.5, PM₁₀, SO₂, NO₂, O₃ and CO from eight air monitoring stations in Chengdu city (Jinquan Lianghe, Shilidian, Sanwayao, Shahepu, Liangjiaxiang, Caotang Temple, People’s Park, Lingyan Temple) from 2013-2015 are used to analyze the spatio-temporal distribution characteristics of various pollutants and to focus on the sources of particulate matter and the causes of spatio-temporal changes. The study shows that: 1) From 2013 to 2015, the annual average concentrations of PM_2.5 , PM₁₀ and SO₂ at each monitoring point in Chengdu city decreased significantly year by year. The monthly and seasonal changes of PM_2.5, PM₁₀, SO₂, NO₂ and CO in all monitoring points except Lingyan Temple are consistent, which shows that the sources of pollutants in Chengdu are similar. The mass concentration of PM_2.5 and PM₁₀ exceeded the standard seriously. The mass concentrations of PM_2.5, PM₁₀, NO₂ and CO in clean con-trol point, Lingyan Temple, are lower than those of the urban monitoring points in Chengdu, O₃ is higher than the monitoring points of the urban area, and SO₂ is not much different from that of the urban areas. 2) A significant spatial correlation exists between the mass concentrations of PM_2.5 and PM₁₀. The mass concentrations of PM_2.5 and PM₁₀ at similar monitoring sites have spatially similar aggregation characteristics. The annual average concentration of PM_2.5 and PM₁₀ in Chengdu and its surrounding areas is spatially lower in the northwest and higher in the southeast, and the PM_2.5 and PM₁₀ pollution in the northwest of the urban area are the most serious. The high concentrations of PM_2.5 and PM₁₀ are significantly moved to the south in autumn, and the trend of increasing in urban area is obvious. 3) Air pollution in Chengdu is dominated by fine particles. The seasonal changes of PM_2.5/PM₁₀ values of all monitoring points are the same, which is winter > autumn > summer > spring. And PM_2.5 and PM₁₀ are greatly affected by industrial combustion (fixed pollution sources) in the spring and vehicle exhaust (mobile pollution sources) in autumn.