[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 x m(-3) (mean = 23.2 pg x m(-3)) and 0.229-10.7 pg x m(-3) (mean = 2.00 pg x m(-3)), respectively. The seasonal variation of PCDD/Fs concentrations was obvious, with the highest concentration was found in spring (37.8 pg x m(-3)) and the lowest in summer (13.5 pg x m(-3)). However, no obvious difference of concentrations was observed for autumn (22.3 pg x m(-3)) and winter (19.1 pg x m(-3)). The seasonal variation of I-TEQ values is as follows: spring (5.58 pg x m(-3)) > summer (1.06 pg x m(-3)) > autumn (0.839 pg x m(-3)) > winter (0.525 pg x m(-3)). The influences of monsoon and rainfall on the concentration of PCDD/Fs in atmosphere are discussed.