中文关键词臭氧单颗粒气溶胶二次气溶胶醛酮化合物光化学氧化 英文关键词ozonesingle particlessecondary aerosolsaldone compoundsphotochemical oxidation

作者	单位	E-mail
吴梦曦	暨南大学质谱仪器与大气环境研究所, 广州 510632 广东省大气污染在线源解析系统工程技术研究中心, 广州 510632	1565330787@qq.com
成春雷	暨南大学质谱仪器与大气环境研究所, 广州 510632 广东省大气污染在线源解析系统工程技术研究中心, 广州 510632
黄渤	暨南大学质谱仪器与大气环境研究所, 广州 510632 广东省大气污染在线源解析系统工程技术研究中心, 广州 510632 广州禾信仪器股份有限公司, 广州 510530
李梅	暨南大学质谱仪器与大气环境研究所, 广州 510632 广东省大气污染在线源解析系统工程技术研究中心, 广州 510632	limei2007@163.com
陈多宏	广东省环境监测中心, 国家环境保护区域空气质量监测重点实验室, 广东省环境保护大气二次污染研究重点实验室, 广州 510308	chenduohong@139.com

中文摘要 为探讨高浓度臭氧（O₃）对气溶胶生成与老化过程的影响，本研究利用单颗粒气溶胶质谱仪（SPAMS）于2018年10月在广东省鹤山大气环境超级监测站进行观测.观测期间根据O₃浓度的高低，定义了高臭氧浓度（P_H）时段和低臭氧浓度（P_L）时段，其中P_H时段O₃平均浓度为117μg·m^-3，P_L时段平均浓度为25μg·m^-3.依据化学组成的不同，观测期间单颗粒主要包含老化元素碳颗粒（EC-aged）、二次颗粒（Sec）和老化有机碳颗粒（OC-aged）.P_H时段单颗粒总数（348085）高于P_L时段（224797），且P_H时段Sec颗粒（37.1%）的占比显著高于P_L时段（27.8%），而EC-aged颗粒（32.1%）则低于P_L时段（44.1%），OC-aged颗粒（13.5%）略高于P_L时段（10.4%）.含硝酸盐（nitrate）和硫酸盐（sulfate）的颗粒数浓度在P_H时段有显著的昼夜变化，而在P_L时段无昼夜变化，Sec颗粒和EC-aged颗粒中硝酸盐和硫酸盐的峰面积P_H时段高于P_L时段，表明在P_H时段通过二次反应过程生成硝酸盐和硫酸盐的量多于P_L时段.此外，Sec颗粒中硝酸盐和硫酸盐的峰面积显著高于EC-aged颗粒，表明Sec颗粒的老化程度更深.本研究选取了乙酸根（⁵⁹CH₃CO₂^-）和乙二醛（⁷³C₂HO₃^-）来代表醛酮化合物在单颗粒气溶胶中的变化特征.P_H时段Sec和OC-aged颗粒中⁵⁹CH₃CO₂^-和⁷³C₂HO₃^-的数浓度与峰面积显著高于P_L时段，且在P_H时段呈现显著的日变化特征，峰值出现在O₃浓度高峰后2 h，在P_L时段峰值显著降低，该变化趋势与Sec和OC-aged颗粒的数浓度变化特征相同，表明高浓度O₃有利于VOCs氧化生成⁵⁹CH₃CO₂^-和⁷³C₂HO₃^-.综上，高臭氧浓度时段光化学反应较强，二次气溶胶组分的含量显著增加，光化学反应增强是P_H时段臭氧浓度升高和单颗粒中二次组分增加的主要原因. 英文摘要 To investigate the effect of high concentration of ozone (O₃) on the aerosol formation and aging process, this study made observations using a single-particle aerosol mass spectrometer (SPAMS) at Heshan Atmospheric Environment Supervision Station in Guangdong Province in October 2018. During the observation period, a high ozone concentration period (P_H) and a low ozone concentration period (P_L) were defined according to the level of O₃ concentration. The average O₃ concentration during P_H was 117 μg·m^-3, and that of P_L was 25 μg·m^-3. According to the difference in chemical composition, single particles mainly included aging element carbon particles (EC-aged), secondary particles (Sec), and aging organic carbon particles (OC-aged) during the observation period. The total number of single particles in P_H (348085) was higher than in P_L (224797), and the proportion of Sec particles (37.1%) in P_H was significantly higher than in P_L (27.8%), whereas the proportion of EC-aged particles in P_H (32.1%) was lower than in P_L (44.1%). The proportion of OC-aged particles in P_H (13.5%) was slightly higher than in P_L (10.4%). The concentration of particles containing nitrate and sulfate showed significant diurnal changes during P_H, but no diurnal changes during P_L. The peak area of nitrate and sulfate in the Sec particles and EC-aged particles in P_H was higher than in P_L, which indicates that the amount of nitrate and sulfate produced by the secondary reaction process in P_H was more than in P_L. In addition, the peak areas of nitrate and sulfate in the Sec particles were significantly higher than those in the EC-aged particles, indicating that the age of the Sec particles was greater. In this study, acetate (⁵⁹CH₃CO₂^-) and glyoxal (⁷³C₂HO₃^-) were selected to represent the changing characteristics of aldehyde and ketone compounds in single-particle aerosols. The number concentration and peak area of ⁵⁹CH₃CO₂^- and ⁷³C₂HO₃^- in Sec and OC-aged particles in P_H were significantly higher than those in P_L, and showed significant diurnal variation characteristic during P_H. The peak appeared 2 h after the peak of O₃ concentration. In P_L, the peak value was significantly reduced, and the change trend was the same as that of the number concentration of Sec and OC-aged particles, indicating that high concentration of O₃ is beneficial to the oxidation of VOCs to ⁵⁹CH₃CO₂^- and ⁷³C₂HO₃^-. In summary, high concentration of O₃ and enhancement of secondary species in single particles were due to the strong photochemical reactions during P_H.

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