Observations and capabilities

This chapter summarizes recent observations and measurements of POPs in various environmental media from which a better understanding of POPs transport on a regional, intercontinental or global scale can be derived. As explained in Chapter 1, POPs and POP-like chemicals are a unique group of pollutants that may be transported via the atmosphere or the ocean and has the ability to partition to and from various environmental media, degrade and transform along the transport pathway. Due to this complexity, an understanding of both primary and secondary emissions, as well as POPs degradation and transformation processes, is essential to interpret observed transport episodes, temporal and spatial trends. In this chapter, we have also summarized currently-available measurement techniques that may provide different types of long-range transport information and analytical techniques used to identify the historical signature and potential sources of POPs. While Chapter 3 provides detail information on the modelling aspects of POPs, specific transport and process models have also been derived and used to explain and elucidate various observed concentrations, trends and transport processes. Readers are referred to Appendix B for summaries of these studies where applicable.