Report on passive samplers for atmospheric chemistry measurements and their role in GAW

One of the main challenges for GAW is to balance the needs of global-scale issues, with regional and urban concerns. Another major challenge is how to accomplish the desires to expand GAW monitoring activities to include measurements for each principal climatic zone and each major biome (some 30 global stations), and to add important species to the measurement list at GAW stations (e.g., NMHCs, aerosols, etc.).
Passive samplers present a means of addressing many of these issues in atmospheric chemistry monitoring, in that they provide a simple and cost effective way of monitoring specific species at urban, regional and global scales, and offer broad capacity building opportunities. While the appropriateness of the use of passive samplers has been questioned in the past due to concerns related to reliability and accuracy, current developments and studies indicate that passive samplers are now a viable option for many species and many applications.
There appears to be a valuable role for the use of passive samplers in GAW, and this is the focus of this discussion paper. This paper begins with a general discussion of the basic principals behind passive samplers (Section 2). Specific details are then presented for a variety of species, including filter preparation, analysis and performance (Section 3). The use of passive samplers in various monitoring programmes is discussed in Section 4. The report concludes with a discussion of the potential uses of passive samplers in GAW (Section 5) and a set of proposed activities (Section 6).