SDI

Dekati Small Deposit Area Impactor (SDI) is a 12 stage cascade low pressure impactor designed especially for applications where small particle collection area is needed. The SDI was originally developed by the Finnish Meteorological Institute to collect size-fractionated aerosol samples in remote locations for subsequent analyses by PIXE (Proton Induced X-ray Emission). The SDI is also suitable for various other types of chemical analyses methods including ion chromatography and EC/OC analyses, and also gravimetric size distribution measurements.

The SDI size classifies particles into 12 size fractions in the size range of 45 nm – 8.5 µm with a sample flow rate of 11 l/min. The relatively high sample flow rate together with the small particle collection area (Ø 8 mm) increase the sensitivity of the particle analyses even when the sample concentration is low. Typical applications for the SDI are particle source apportionment studies, background concentration measurements and indoor and outdoor air quality measurements.