Measurement Methods for Nanoparticles in Indoor and Outdoor Air

Abstract

A large variety of measurement methods for the characterization of airborne nanoparticles in indoor or outdoor air exist. The choice of an appropriate method depends strongly on the questions to be tackled. If the aerosol is to be characterized only for a single location, one may use stationary equipment that is rather bulky but provides the most details and is most accurate. Spatially resolved measurements can only be conducted with portable or personal measurement equipment which provide a limited dataset with lower accuracy. Furthermore, the metrics to be measured (e.g., number, surface area of mass concentration, chemical composition, etc.) determine the choice of measurement methods as no single method can do it all. Another determining factor is the time resolution of the instruments. While direct-reading monitors deliver the information with high time resolution (often 1s) and hence allow for linking the measured concentration to certain activities, samplers collect the particles for subsequent analyses and therefore provide an average over the sampling time. Consequently, the choice of a measurement instrument for the characterization of airborne nanoparticles remains a compromise. In many practical applications, the combination of different techniques may be required.