应用扩散管测量霾污染期间大气氮硫化合物浓度的方法

发布时间：2018-03-11 04:36

本文选题：霾污染　切入点：颗粒物　出处：《环境科学》2017年09期 　论文类型：期刊论文

【摘要】：活性氮和硫化合物在大气颗粒物形成过程中扮演重要角色,但对它们气相/颗粒相的同步观测结果比较缺乏.本研究尝试基于扩散管的DELTA系统测量氮和硫化合物短时累积浓度,以期捕捉它们在霾污染期间的演变规律.结果表明,DELTA系统收集气态污染物的扩散管中以及颗粒物滤膜上NH_4~+和NO-3空白干扰较小,适用于研究NH_3、HNO_3、NH_4~+和NO-3的日均浓度,可以作为城市环境空气质量监测参数的有效补充;但采样系统中SO_2-4背景含量较高,仅适合监测48 h以上时间尺度的SO_2浓度和周~月尺度SO_2-4浓度,用于大气硫沉降观测.北京2016年5月9日~6月7日观测期间,大气NH_3、HNO_3、NH_4~+和NO-3浓度具有明显的逐日演变规律,呈现出随着风向转变而发生周期性波动的典型特征;这些含氮污染物与PM_(2.5)、CO、SO_2和NO_2浓度的变化规律一致,其来源可能与化石燃料燃烧源有关.污染天NH_3、HNO_3、NH_4~+和NO-3浓度约为清洁天的2倍,但还原性氮和氧化性氮的相态分布在清洁天和污染天无明显差异;整个观测期间,HNO_3/NO-3约为1.2,NH_3/NH_4~+为4.5,春夏之交较高的温度有利于活性氮在气粒平衡过程中偏向于气态形式存在.
[Abstract]:Active nitrogen and sulfur compounds play an important role in the formation of atmospheric particulates, but the simultaneous observation results of their gas phase / particle phase are scarce. In this study, DELTA system based on diffusion tube was used to measure the short-term cumulative concentrations of nitrogen and sulfur compounds. The results show that the NH _ 4 ~ and NO-3 blank interference is small in the diffusion tube and the filter membrane of particulate matter, so it is suitable for studying the daily average concentration of NH _ 3HNO _ 3s and NO-3 in the dispersion tube and the filter membrane of particulate matter, which is suitable for studying the daily concentration of NH _ 3H _ no _ 3s and NH _ 4 ~ and NO-3 in the diffusion tube and the filter membrane of particulate matter. It can be used as an effective supplement to the monitoring parameters of urban ambient air quality, but the background content of SO_2-4 in the sampling system is relatively high, so it is only suitable for monitoring the concentration of SO_2 at the time scale of more than 48 h and the concentration of SO_2-4 at the scale of week to month. During the observation period from May 9th 2016 to June 7th in Beijing, the concentration of NH _ 3HNO _ 3C _ 4 ~ and NO-3 in the atmosphere has obvious daily evolution law, showing the typical characteristic of periodic fluctuation with the wind direction change. These nitrogen-containing pollutants are consistent with the variation of NO_2 and NO_2 concentrations, and their sources may be related to the sources of fossil fuel combustion. In polluted days, the concentrations of NH _ 3N _ 3N _ 3NH _ 4 ~ and NO-3 are about twice as high as those of clean days. However, there is no significant difference between the phase distribution of reductive nitrogen and oxidized nitrogen in clean and polluted days, and during the whole observation period, the number of HNO3 / No-3 is about 1.2 ~ 4.5. The higher temperature between spring and summer is favorable to the existence of active nitrogen in the process of gas-particle equilibrium.
【作者单位】：中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室;中国农业大学资源与环境学院教育部植物-土壤相互作用实验室;中国科学院生态环境研究中心城市与区域生态国家重点实验室;
【基金】：国家自然科学基金项目(41405144,41425007) 国家重点研发计划项目(2016YFD0800302,2016YFC0201802,2017YFC0210101) 北京市科委科技创新中心建设战略研究及专家咨询专项研究项目(Z171100003217064)
【分类号】：X831

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