长沙市大气中醛酮类化合物浓度变化特征

Variation Characteristics of Atmospheric Carbonyl Compounds in Changsha

参照美国环保署EPA-TO11标准方法,于2014年7—10月监测了长沙市大气中醛酮类化合物的质量浓度。主要监测到的醛酮类化合物为甲醛、乙醛、丙酮、丙醛、甲基丙烯醛,夏季质量浓度最高的是甲醛(13. 86 mg/m^3),其次是乙醛(7. 28 mg/m^3)、丙酮(7. 14 mg/m^3),秋季质量浓度最高的是甲醛(10. 31 mg/m^3),其次是丙酮(8. 37 mg/m^3)、乙醛(5. 78 mg/m^3)。夏季醛酮类化合物的总量高于秋季,甲醛、乙醛、丙酮的质量浓度最大值基本出现在13:00—15:00。C1/C2(甲醛/乙醛)、C2/C3(乙醛/丙醛)的平均值分别为2. 02、10. 19。分析了醛酮类化合物之间的相关性以及它们可能的来源。丙醛和甲醛、乙醛的相关性较好,三者有共同的人为来源。夏季大气中除丙酮外,其他醛酮类化合物的相关性均较好。夏季甲基丙烯醛和甲醛、乙醛、丙酮有相同的自然来源。综合分析可知,长沙大气中醛酮类化合物质量浓度受自然因素和人为因素的双重影响。

The levels of carbonyl compounds in ambient air of Changsha City were measured from July 2014 to October 2014,referred to EPA-T011 method.Formaldehyde,acetaldehyde,acetone,propionaldehyde and MACR(methacrolein)were the predominant carbonyls in Changsha city.The highest concentration was formaldehyde(13.86 mg/m^3),followed by acetaldehyde(7.28 mg/m^3)and acetone(7.14 mg/m^3)in summer,and the highest concentration was formaldehyde(10.31 mg/m^3),followed by acetone(8.37 mg/m^3)and acetaldehyde(5.78 mg/m^3)in autumn.The total amount of carbonyls in summer was higher than that in autumn,and the maximum concentrations of formaldehyde,acetaldehyde,and acetone mostly appeared at 13:00-15:00.The average values of C1/C2(formaldehyde/acetaldehyde)and C2/C3(acetaldehyde/propionaldehyde)were 2.02 and 10.19,respectively.The correlation between carbonyls and their possible sources were analyzed.The correlation between propionaldehyde and formaldehyde and acetaldehyde was good,and they had the same human sources.The correlation of carbonyls in the atmosphere was good in summer except acetone.In summer,methacrolein and acetaldehyde,acetone had the same natural source.In summary,the concentration of carbonyls in the ambient air in Changsha were affected by both natural and human factors.