Interlaboratory comparison of PM10 and black smoke measurements in the peace study.

Abstract This paper presents the results of a comparison of ambient particle measurements conducted by 14 European laboratories in the framework of a multi-center epidemiologic study of Pollution Effects on Asthmatic Children in Europe (PEACE). Measurement of the concentration of particles less than 10 μm (PM10) and black smoke in ambient air was an important component of the PEACE study. The Harvard impactor was used by most laboratories for PM 10 sampling, but Hivol samplers, β gauge and dichotomous samplers were also used. A field study comparing these samplers with the Harvard impactor was conducted at five study sites. Systematic differences between PM10 measured with local samplers and a Harvard Impactor were between −13 and + 18%. A high correlation between PM 10 from the local sampler and the Harvard Impactor was found for four of the five centers. A field comparison of two identical black smoke samplers using either a membrane filter or the standard Whatman 1 paper filter showed an almost threefold difference in BS concentration. This illustrates the importance of using the standard filter. A similar comparison between two different filter papers showed only small differences in BS concentrations. Considerable differences were found in an interlaboratory comparison between two centers and the other centers in reflectance measurements of exposed filters. This difference could largely be attributed to the use of different blanks in setting the reflectometer to 100 before performing the measurements. Systematic differences in weighing Teflon test filters were present between the laboratories. Since these differences were similar for exposed and blank filters for 12 of the 13 centers, only small differences in PM10 concentration ( −3 ) were expected due to differences in weighing.