Improved correction method for using passive air samplers to assess the distribution of PCNs in the Dongjiang River basin of the Pearl River Delta, South China

An improved correction method was established using passive air samplers to assess the distributions of polychlorinated naphthalenes (PCNs) in the eastern Pearl River Delta, South China. This method was based on a joint correction that used the active air sampling rate and the addition of depuration compounds. As a correction factor, the depuration compounds’ properties do not need to be similar to the target compounds. The total PCN air concentrations ranged from 6.4 to 832, with an average of 148 ± 201 pg m−3 in the study area, while the TEQ of the PCNs ranged from 1.2 × 10−4 to 2.6 × 10−2 pg m−3. High concentrations of PCNs were mostly observed in the highly industrialized areas. The PCN air levels were remarkably increased in winter compared with summer. Tri-CNs was the most dominant homologue group, while CN 24 was the most dominant congener. The high proportion of combustion-related PCNs suggests that the contribution of combustion sources to the PCN air burden has been significant recently in comparison with historical emissions.

► An improved correction method for passive air sampler was established.
► Air distributions of PCNs in the PRD were assessed using this method.
► High concentrations of PCNs were mostly observed in the highly developed areas.
► The contribution of combustion PCN sources has been increasing recently.