林昕,黄明强,张威,卢婷婷,蔡顺有,赵卫雄,胡长进,顾学军,张为俊.硫酸铵细粒子对苯二次有机气溶胶光学特性的影响[J].环境科学学报,2021,41(7):2560-2568
硫酸铵细粒子对苯二次有机气溶胶光学特性的影响
- Effects of ammonium sulfate fine particle on the optical properties of benzene secondary organic aerosol
- 基金项目：国家自然科学基金（No.41575118）；福建省自然科学基金（No.2020J02044）
- 林昕
- 闽南师范大学化学化工与环境学院, 福建省现代分离分析科学与技术重点实验室, 漳州 363000
- 黄明强
- 闽南师范大学化学化工与环境学院, 福建省现代分离分析科学与技术重点实验室, 漳州 363000
- 张威
- 闽南师范大学化学化工与环境学院, 福建省现代分离分析科学与技术重点实验室, 漳州 363000
- 卢婷婷
- 闽南师范大学化学化工与环境学院, 福建省现代分离分析科学与技术重点实验室, 漳州 363000
- 蔡顺有
- 闽南师范大学化学化工与环境学院, 福建省现代分离分析科学与技术重点实验室, 漳州 363000
- 赵卫雄
- 中国科学院安徽光学精密机械研究所大气物理化学实验室, 合肥 230031
- 胡长进
- 中国科学院安徽光学精密机械研究所大气物理化学实验室, 合肥 230031
- 顾学军
- 中国科学院安徽光学精密机械研究所大气物理化学实验室, 合肥 230031
- 张为俊
- 中国科学院安徽光学精密机械研究所大气物理化学实验室, 合肥 230031
- 摘要：苯系物光氧化产生的二次有机气溶胶（SOA）能够散射、吸收大气辐射，扰动区域气候变化.硫酸铵（（NH4）2SO4）是大气中常见的无机细粒子，其大的比表面积可作为半挥发性化合物凝结和反应中心，进而影响SOA的化学组分和光学特性.本文采用烟雾箱研究（NH4）2SO4细粒子对苯SOA在200~600 nm范围内的平均质量吸收系数（mass absorption coefficient，MAC）的影响情况.实验结果表明，低浓度（小于100 μg·m-3）（NH4）2SO4细粒子仅作为凝结核心，不会影响苯SOA的光学性质.高浓度（大于100 μg·m-3）（NH4）2SO4细粒子对咪唑类吸光产物的形成有促进作用.苯SOA的MAC值随着（NH4）2SO4细粒子浓度的增加而逐渐增大，却随着细粒子酸度的增大而逐渐减小.水分子的增加会产生更多的NH4+，从而有利于咪唑类化合物的产生，苯SOA的MAC值则随着相对湿度的增加而逐渐增大.而当相对湿度高于70%时，乙二醛水合反应增强，四醇产物脱水、聚合形成的高分子量产物增多，从而导致MAC值减小.这为研究高浓度（NH4）2SO4细粒子背景下，人为源SOA的光学特性提供了实验依据.
- Abstract：Secondary organic aerosol (SOA) formed from the photooxidation of aromatic hydrocarbons can scatter and absorb atmospheric radiation and disturb regional climate change. Ammonium sulfate ((NH4)2SO4) is the common inorganic fine aerosol particle in atmosphere. Its large specific surface area can be used as the condensation and reaction center of semi-volatile compounds, thus affecting the chemical components and optical properties of SOA. The effect of (NH4)2SO4 fine particle on the mass absorption coefficient averaged over 200~600 nm (MAC) of benzene SOA was investigated with smog chamber in this study. The experimental results demonstrated that low concentration (less than 100 μg·m-3) of (NH4)2SO4 fine particle only act as the condensation core, and do not affect the optical properties of benzene SOA. High concentration (more than 100 μg·m-3) of (NH4)2SO4 fine particle can promote the formation of imidazole absorption products. The MAC value of benzene SOA gradually increases with the increasing of the concentration of (NH4)2SO4 fine particles, but gradually decreases with the increasing of the acidity of the fine particles. The increase of water molecules would produce more NH4+ ions, which is conducive to the formation of imidazole compounds. The MAC value of benzene SOA increases with the increasing of relative humidity. However, when the relative humidity is higher than 70%, the hydration reaction of glyoxal is enhanced, and the dehydration and polymerization of tetranol products increase, resulting in the decrease of MAC value. These would provide the experimental basis for studying the optical properties of anthropogenic SOA in the background of high concentration of (NH4)2SO4 fine particle.
