ISO 21438-3:2026

This document specifies a method for the determination of the time-weighted average mass concentration of soluble particulate fluorides and hydrofluoric acid (HF) in workplace air by collection of the particulate fluorides on a pre-filter and HF on an alkali-impregnated filter and analysis by ion chromatography. This method is only applicable to determination of particulate fluorides that are soluble using the sample preparation procedure specified. For aerosol sampling, this method is applicable to the personal sampling of the inhalable fraction of airborne particles, as defined in ISO 7708, and to static (area) sampling. The method is applicable to the determination of masses of 0,005 mg to at least 1,25 mg of particulate fluorides per sample and 0,015 mg to at least 1,2 mg of HF per sample.