冬、春季青岛大气气溶胶中乙二酸的分布特征及影响因素

于2012-12~2013-04在青岛采集119个气溶胶样品，分析了冬、春季节气溶胶中乙二酸的浓度分布特征及影响因素.青岛大气气溶胶中乙二酸的浓度冬季为31~370 ng·m^-3，平均为104 ng·m^-3；春季为11~1926 ng·m^-3，平均为400 ng·m^-3，二者存在显著的季节差异.不同天气状况影响气溶胶中乙二酸的分布，霾天时乙二酸浓度最高，其次是沙尘天，雾天与晴天时的基本相当，雨天时的浓度最低.青岛大气气溶胶中乙二酸与温度和太阳辐射之间存在显著正相关关系，表明光化学氧化的二次生成过程对气溶胶中的乙二酸有一定影响.冬、春季气溶胶中乙二酸二次生成的机理可能不同，冬季主要为水相氧化过程、春季为气相氧化过程.PMF源解析结果也显示，二次源是青岛大气气溶胶中乙二酸的主要来源，其贡献冬季约为45%、春季约为70%.春季青岛气溶胶中乙二酸浓度显著高于冬季，其主要原因可能是春季温度和太阳辐射显著高于冬季，增强了颗粒态乙二酸的二次生成过程.

Distribution of Oxalate in Atmospheric Aerosols and the Related Influencing Factors in Qingdao, During Winter and Spring

A total of 119 total suspended particle (TSP) samples were collected in Qingdao from December 2012 to April 2013. Concentrations of oxalate in TSP were measured to investigate the distributional characteristics of oxalate and the related influencing factors, in winter and spring. The concentrations of oxalate in Qingdao aerosols were 31-370 ng·m^-3 with an average of 104 ng·m^-3 in winter, and 11-1926 ng·m^-3 with an average of 400 ng·m^-3 in spring, with a significant difference between the concentrations in the two seasons. Different weather conditions affected the distribution of oxalate in aerosols. The oxalate concentration in TSP was the highest in the hazy days, followed by that in the dusty days, while this concentration in foggy days was close to that in the clear days, and the lowest concentration of oxalate appeared in the rainy days. Oxalate in Qingdao aerosols exhibited a significant positive correlation with temperature and solar radiation, suggesting that the secondary production of oxalic acid via photochemical oxidation has an important contribution to the oxalate concentrations in aerosols. The mechanisms of secondary formation of oxalate in aerosols in winter and spring are possibly different, with the aqueous phase oxidation process predominating in winter and the gas-phase oxidation-driven process predominating in spring. The results of PMF source analysis also showed that the secondary formation is the main source of oxalate in Qingdao aerosol, and its contribution to oxalate production is nearly 45% in winter and 70% in spring. The concentration of oxalate in spring aerosol was significantly higher than that in winter aerosol, the main reason of which was that temperature and solar radiation in spring were significantly higher than those in winter, promoting the secondary formation of particulate oxalate.