广州某工业区大气中PCDD/Fs含量水平及其季节性变化特征

通过对广州某工业区大气中2,3,7,8-PCDD/Fs的季节性监测,并对大气中PCDD/Fs的浓度与季节性变化进行了分析.结果表明,该工业区大气中PCDD/Fs的浓度范围为2.33~75.4 pg·m-3,平均值为23.2 pg·m-3,毒性当量浓度I-TEQ范围为0.229~10.7 pg·m-3,平均值为2.00 pg·m-3,高于日本环境空气质量标准推荐年均值0.6 pg·m-3.该工业区PCDD/Fs浓度季节性变化明显,最高的季节为春季(37.8 pg·m-3),浓度最低的季节为夏季(13.5 pg·m-3),其次为秋季(22.3 pg·m-3)和冬季(19.1 pg·m-3);毒性当量浓度变化高低顺序为:春季(5.58 pg·m-3)>夏季(1.06 pg·m-3)>秋季(0.839 pg·m-3)>冬季(0.525 pg·m-3).降雨、季风的季节性变化可能是引起大气中PCDD/Fs浓度季节性变化的原因.

Seasonal Variation of Concentrations and Distribution Characteristics of PCDD/Fs in Atmosphere of an Industrial Area, Guangzhou

Atmospheric concentrations of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were measured seasonally in an industrial area of Guangzhou City. And seasonal variation of concentrations and distribution characteristics of 2,3,7,8- PCDD/Fs was investigated. The PCDD/Fs concentrations and corresponding I-TEQ (toxic equivalent quantity) values were in the range of 2.33-75.4 pg·m^-3 (mean=23.2 pg·m^-3) and 0.229-10.7 pg·m^-3 (mean=2.00 pg·m^-3), respectively. The seasonal variation of PCDD/Fs concentrations was obvious, with the highest concentration was found in spring (37.8 pg·m^-3) and the lowest in summer (13.5 pg·m^-3). However, no obvious difference of concentrations was observed for autumn (22.3 pg·m^-3) and winter (19.1 pg·m^-3). The seasonal variation of I-TEQ values is as follows: spring (5.58 pg·m^-3)>summer (1.06 pg·m^-3)>autumn (0.839 pg·m^-3)>winter (0.525 pg·m^-3). The influences of monsoon and rainfall on the concentration of PCDD/Fs in atmosphere are discussed.