Loss of Nanoparticles in a Particulate Matter Sampling System Applied for Environmental Ultrafine Particle Measurements

Abstract

AbstractCurrent air monitoring networks consist of many measuring stations equipped with sampling systems for the measurement of PM2.5 and PM10 particulate matter. To measure the quantity of particulate matter, the sample air flow is fed to the measuring device through a sampling system. In Baden Württemberg, but also across a wide area in Germany, these sampling systems consist of a Sigma-2-Sampling Head (manufacturer Palas GmbH) and an Intelligent Aerosol Drying System (IADS, manufacturer Palas GmbH). To investigate the suitability of these two common components for sampling of ultrafine particles (< 100 nm), the particle loss inside a sampling system consisting of a Sigma-2-Sampling Head, an IADS, and an additional nafion-dryer (MD-700-24S-1, manufacturer Perma Pure LLC) is measured in this study. A low sampling flow rate of only 0.9 l/min was employed to reduce energy consumption, complexity, and the cost of additional instrumentation. This sample flow rate is typical for scanning mobility particle sizers which are commonly used to measure ultrafine particles. The investigations show a 37% loss of spherical 10 nm copper particles in the used sampling system, which is higher than the allowed losses specified in DIN CEN/TS 16976 for 7 nm particles. The root cause of these losses was investigated and correlations were derived to describe the particle penetration in the sampling system.