Abstract: The invention relates to a method for determination of ambient mineral dust concentration based on optical absorption of particles concentrated by a virtual impactor as well as a device performing the said method. The method comprises the following steps: Sampling air samples with particle size smaller than 1 ?m (PM1) and sampling air samples with particle size up to 10 ?m; Concentrating the samples with particle sizes up to 10 ?m with a virtual impactor; Measuring optical absorption of collected samples at least one wavelength from UV to IR spectre, preferably from 370 to 950 nm, most preferably at 370 nm; Subtracting the absorption of the samples with particle size smaller than 1 ?m from the absorption of the sample concentrated by the virtual impactor.

Abstract: The invention relates to a method for determination of ambient mineral dust concentration based on optical absorption of particles concentrated by a virtual impactor as well as a device performing the said method. The method comprises the following steps: Sampling air samples with particle size smaller than 1 ?m (PM1) and sampling air samples with particle size up to 10 ?m; Concentrating the samples with particle sizes up to 10 ?m with a virtual impactor; Measuring optical absorption of collected samples at least one wavelength from UV to IR spectre, preferably from 370 to 950 nm, most preferably at 370 nm; Subtracting the absorption of the samples with particle size smaller than 1 ?m from the absorption of the sample concentrated by the virtual impactor.