On the detection efficiency of ultrafine condensation particle counter (ucpc, tsi model 3025) below 3 nm

Abstract

Ultrafine aerosol particles (diameter of 1–20 nm) are in central position in several gas-to-particle conversion mechanisms in both atmospheric and industrial processes. Understanding of these processes often requires instrumentation on ultrafine particle size range. The ultrafine condensation particle counter (UCPC) is designed to detect particles down to 2.7 nm. UCPC's principle of operation is based on condensing of butanol vapor onto particles and optical counting of activated and enlarged particles. This chapter discusses the physicochemical features affecting the activation of aerosol particles inside the condenser of the CPC. There are two main subjects of interest—namely the smallest detectable size or in other words the concept of Kelvin diameter and, second, CNC's operation on particles of different material. Because Stolzenburg and McMurry have already studied the subject quite carefully, this chapter concentrates on the logarithmic behavior of the descending detection efficiency below 3nm.