中文关键词
二次污染物热力学模型颗粒酸度颗粒含水水溶性离子(WSIs) 英文关键词secondary pollutantsthermodynamic modelparticle acidityliquid water content of particlewater-soluble ions(WSIs) |
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中文摘要 |
大气二次污染物是新疆独山子区大气污染物的重要组成部分,研究大气中二次组分的转化过程对区域大气污染治理有着重要意义.对新疆独山子区2015年9月至2016年7月采集到的样品进行水溶性组分分析.结果表明,水溶性无机离子(TWSIs)表现出与PM2.5一致的季节变化,为冬季(67.86 μg·m-3) > 秋季(13.77 μg·m-3) > 春季(10.09 μg·m-3) > 夏季(4.85 μg·m-3);冬季二次无机离子(NH4+、SO42-和NO3-)占TWSIs的98%;结合气溶胶热力学模型(E-AIM)探讨独山子区大气颗粒污染物中颗粒相含水量以及颗粒酸碱性;表明独山子区颗粒物呈酸性,年均原位pH为0.81,其中冬季样品的pH(2.93)值最高;颗粒含水季节变化为冬季(331.32 μg·m-3) > 秋季(5.91 μg·m-3) > 春季(5.46 μg·m-3) > 夏季(1.62 μg·m-3);年均氮氧化率(NOR)和硫氧化率(SOR)分别为0.13和0.47,表明区域污染物存在二次转化;进一步分析表明颗粒相中的硫酸盐质量浓度受到颗粒含水量和颗粒酸碱度的影响较为明显;高的颗粒相含水条件下区域硝酸盐的形成主要以非均相反应为主. |
英文摘要 |
Secondary species are dominant components of PM2.5 in Dushanzi, Xinjiang. It is crucial to investigate the conversion process of secondary components in the atmosphere for regional air pollution control. The water-soluble components were analyzed for samples collected from Dushanzi District of Xinjiang from September 2015 to July 2016. The results showed that the total water-soluble ions (TWSIs) showed a seasonal variation consistent with PM2.5, and the seasonal variation of the ions was in the order—winter (67.86 μg·m-3) > autumn (13.77 μg·m-3) > spring (10.09 μg·m-3) > summer (4.85 μg·m-3); secondary ions (NH4+, SO42-, and NO3-)—accounting for 98% of TWSIs in winter. The results of the aerosol thermodynamic model (E-AIM) that explores the particle liquid water and acidity in Dushanzi District showed that the particles in Dushanzi are acidic with an annual in-situ pH of 0.81, and the pH value of the winter samples was the highest (2.93). The seasonal variation of particles in water was of the order: winter (331.32 μg·m-3) > autumn (5.91 μg·m-3) > spring (5.46 μg·m-3) > summer (1.62 μg·m-3). The annual average nitrogen oxidation rate and sulfur oxidation rate were 0.13 and 0.47, respectively, indicating a secondary conversion of regional pollutants. Further analysis showed that the concentration of sulfate in the particle phase was significantly affected by liquid water content of particles and in-situ pH. The formation of nitrate was mainly caused by heterogeneous reactions under high water content of particle. |
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