A review of PCB-11 and other unintentionally produced PCB congeners in outdoor air

This review summarizes up-to-date scientific literature concerning unintentionally produced polychlorinated biphenyls (UP-PCBs), including information on their known or suspected formation pathways, occurrence in air globally, and properties relating to atmospheric persistence and transport. Prior to the listing of PCBs as an original dirty dozen persistent organic pollutant (POP) under the Stockholm Convention on Persistent Organic Pollutants, they were already widely regulated, and some monitoring in air was occurring due to environmental and health concerns. So far, the focus of monitoring has been for dominant congeners found in technical PCB formulations, such as Aroclors. However, recent research has shown that processes such as dye/pigment manufacturing, and industrial thermal processes have resulted in UP-PCB emission and detection globally. It is especially concerning that UP-PCBs make up a significant proportion of Sigma PCBs (typically from a few percent to as high as 85%), and this contribution continues to increase. Among identified UP-PCBs, PCB-11 is the dominant congener detected in air. Three key recommendations from this review include i.) to include UP-PCBs, such as PCB-11 and PCB-209, as indicator congeners in air monitoring and research programs; ii.) to apply PUF disk passive air samplers as simple and cost-effective tools for generating new information on global air; and iii.) to identify and quantify the ongoing emission sources of UP-PCBs to air. The new information will raise awareness to the growing problem of UP-PCBs and could inform science and policy strategies for assessing and managing this emerging class of chemicals.

Automated summary

This review summarizes the latest scientific literature on unintentionally produced polychlorinated biphenyls (UP-PCBs), including their formation pathways, global occurrence in air, and properties related to atmospheric persistence and transport. Recent research has shown that processes such as dye/pigment manufacturing and industrial thermal processes have led to global emissions and detection of UP-PCBs. It is concerning that UP-PCBs contribute a significant proportion to total PCBs and their contribution is increasing. The review recommends including UP-PCBs as indicator congeners in air monitoring and research programs, using PUF disk passive air samplers for generating new information on global air, and identifying and quantifying ongoing emission sources of UP-PCBs to air.