| 拉萨市挥发性有机物的组成特征、季节变化和来源解析 |
| 摘要点击 2255 全文点击 736 投稿时间：2021-04-05 修订日期：2021-06-24 |
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| 中文关键词 挥发性有机污染物(VOCs) 正定矩阵因子分解法(PMF) 拉萨 组成特征 来源解析 |
| 英文关键词 volatile organic compounds(VOCs) positive matrix factorization(PMF) Lhasa component and characteristics source apportionment |
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| 中文摘要 |
| 目前在世界范围内，由于高原城市海拔高、紫外线照射强烈，造成大气中挥发性有机物的源汇归趋呈现较独特的特点.本研究对2019年拉萨市2个城市站点和1个背景站进行大气挥发性有机物（VOCs）的离线罐采样及实验室组分分析，探究了拉萨地区VOCs体积分数水平、组成特征和来源贡献.拉萨市平均φ（VOCs）为49.83×10-9，其中烷烃类最高，占比为61%，其次为含氧VOCs（OVOCs，12%）、卤代烃（9%）、烯烃（9%）、芳香烃（5%）和炔烃（4%）.拉萨市市区站点中，八廓街站和区辐射站的VOCs源贡献顺序为：燃烧源（分别为64%和48%，下同） > 交通排放（17%和31%） > 工业排放（14%和14%） > 溶剂涂料（3%和3%）≈植物+背景（2%和4%）.八廓街站燃烧源贡献大，与当地贡香焚烧和供暖排放有关；区辐射站的交通排放贡献较高，与距离交通枢纽近且上风向物流中心有关；工业排放对VOCs具有区域性影响.拉萨地区的VOCs体积分数、组分特征、源类贡献受气象和排放协同影响，呈现明显季节变化和地区差异.本研究可以提供我国典型高原城市的VOCs组成特征，可为高源城市臭氧形成和驱动因素的研究积累基础数据. |
| 英文摘要 |
| Due to the high altitude of plateau cities and strong ultraviolet radiation, the sources and fates of volatile organic compounds show unique characteristics. In this study, the atmospheric volatile organic compound (VOCs) samples were collected at two urban sites and one background site using tank sampling in Lhasa in 2019, and then the composition, concentration, and sources were characterized. The results showed that the average φ(VOCs) in Lhasa was 49.83×10-9, of which the proportion of alkanes was the highest (61%), followed by OVOCs (12%), halogenated hydrocarbons (9%), olefin (9%), aromatic hydrocarbons (5%), and alkynes (4%). The respective contributions of VOCs sources at urban sites, such as Barkhor Street and Radiation Station in Lhasa, were as follows:combustion (64% and 48%) > traffic emission (17% and 31%) > industrial emission (14% and 14%) > solvents and coatings (3% and 3%) ≈plant+background (2% and 4%). The contribution of combustion was large mostly due to local incense burning (especially at Barkhor Street) and heating emissions. Traffic emissions contributed about one third to the VOCs at Radiation Station, which is related to its proximity to the transportation hub and the storage and logistics center upwind. Industrial emissions have a regional impact on ambient VOCs. Under the synergistic influence of meteorology and emissions, VOCs concentration, composition characteristics, and source contribution showed obvious seasonal variations and site differences in the Lhasa area. |
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