高原城市昆明公路隧道大气中PM_(2.5)理化特征分析  

Physico-chemical Characteristic Analysis of PM_(2.5)in the Highway Tunnel in the Plateau City of Kunming

作　　者：王成辉 闫琨[2] 韩新宇[1] 施择[2] 毕丽玫 向峰[1,2] 宁平[1] 史建武[1] 

机构地区：[1]昆明理工大学环境科学与工程学院,昆明650500 [2]云南省环境监测中心站,昆明650000

出　　处：《环境科学》2017年第12期4968-4975,共8页Environmental Science

基　　金：国家自然科学基金项目(21667014;21567012;21207055);云南省社会发展科技项目(2012CA016)

摘　　要：为研究高原地区机动车尾气排放特征,选取昆明市草海隧道内大气PM_(2.5)为研究对象,并对样品中的水溶性离子、碳组分、多环芳烃、无机元素进行分析.结果表明,隧道内PM_(2.5)质量浓度为225.65~312.84μg·m^(-3),是同期环境大气中PM_(2.5)浓度的11~14倍,PM_(2.5)中碳组分所占比重最高,约占总质量浓度的35.73%,其次无机元素占21.78%,离子组分在4.79%~5.52%之间,含量最低的是多环芳烃,占0.25%~0.32%;离子组分中Ca^(2+)和SO_4^(2-)含量较高,占总离子浓度的77.78%~80.17%,显示为地壳来源,其次是NH_4^+、NO_3^-的浓度也相对较高,主要来自机动车尾气源;草海隧道PM_(2.5)中以分子量相对较大、不易挥发的4、6环PAHs为主,机动车尾气对PM_(2.5)中多环芳烃的贡献十分显著,毒性最强的Ba P浓度是国家规定浓度限值的23~29倍,高原草海隧道大气中存在PM_(2.5)暴露健康风险;隧道大气PM_(2.5)中元素由PCA分析显示机动车尾气和道路扬尘来源占比约61.64%,其次机械磨损排放源占比约为17.49%,最后为轮胎磨损排放源,占比为9.11%;云贵高原大气低压低氧条件下,机动车发动机燃料不完全燃烧几率较高,导致机动车尾气PM_(2.5)中的OC以及PAHs排放量增加.This research aimed to determine the characteristics of the motor vehicle exhaust emissions in the plateau area. The PM2. 5 was evaluated in the Caohai Tunnel of Kunming for this study by measuring the water-soluble inorganic ions, carbonaceous species, polycyclic aromatic hydrocarbons （PAHs）, and inorganic elements in air samples. The results showed that the mass concentration of PM2. 5 in the tunnel was about 225. 65-312. 84 μg·m - 3 , which is 11-14 times the PM2. 5 concentration in the ambient atmosphere. The carbonaceous species were the most abundant species, constituting 35. 73% of the total PM25 mass, followed by inorganic elements constituting about 21. 78% and the water-soluble inorganic ions in the range of 4. 79% -5. 52% . The smallest proportion of the PM2. 5 was PAH, constituting about 0. 25% -0. 32% . The Ca2 ＋ and SO2 -4 concentrations were the highest among the water-soluble inorganic ions, which accounted for about 77. 78% - 80. 17% of the total ions and from the crust source. NH ＋4 and NO -3 are relatively high, coming mainly from automobile exhausts. The 4 and 6 ring PAHs with higher molecular weight and lower volatility were the dominant components of PM2. 5 in the Caohai Tunnel. The automobile exhaust contributing to PAHs in PM2. 5 is very significant. The most poisonous single BaP concentration is 23- 29 times higher than the state regulations exposure limit, and it has reached a hazardous level. It is obvious that there are health risks from the exposure to PM2. 5 in the plateau highway tunnel. A principal component analysis （PCA） showed that the sources of road dust and automobile exhaust emission were about 61. 64% , followed by mechanical wear and emissions that accounted for about 17. 49% and tire wear emission sources that accounted for 9. 11% of the total PM2. 5 . Under the conditions of hypobaric hypoxia in the Yun-Gui plateau, there is a greater chance of incomplete combustion of motor vehicle fuels, resulting in the increase in OC and PAHs in PM2. 5 emissions.

关 键 词：PM2.5 高原隧道 化学组分 机动车尾气 主成分分析 

分 类 号：X513[环境科学与工程—环境工程]