A collecting device for collection of airborne particles exhaled by a human being, said collecting device comprising: a first layer and a second layer, wherein the first layer and the second layer are arranged to be spaced apart for forming a particle collection chamber (240; 340) between the first and the second layer, wherein the first layer comprises a plurality of inlets (210; 310) configured to extend through the first layer for transporting a flow of air therethrough into the particle collection chamber (240; 340); wherein ends of the inlets (210; 310) are configured to face a first surface of the second layer for capturing airborne particles in the flow of air entering the particle collection chamber (240; 340) through the ends of the inlets (210; 310) by impaction of airborne particles on the first surface of the second layer; wherein the second layer comprises a plurality of outlets (230; 330) configured to extend through the second layer for transporting the flow of air therethrough out of the particle collection chamber (240; 340); the collecting device further comprising at least one liquid access port (260; 260a, 260b; 360a-360h) for filling the particle collection chamber (240; 340) with a reagent; and wherein the particle collection chamber (240; 340) comprises at least one side wall (246; 346) extending from the first layer to the second layer for defining flow of the reagent through the particle collection chamber (240; 340) when filling the particle collection chamber (240; 340), such that a first portion (248a; 348a) of the particle collection chamber (240; 340) and a second portion (248b; 348b) of the particle collection chamber (240; 340) are arranged on opposite sides of the at least one side wall (246; 346). a first layer and a second layer, wherein the first layer and the second layer are arranged to be spaced apart for forming a particle collection chamber (240; 340) between the first and the second layer, wherein the first layer comprises a plurality of inlets (210; 310) configured to extend through the first layer for transporting a flow of air therethrough into the particle collection chamber (240; 340); wherein ends of the inlets (210; 310) are configured to face a first surface of the second layer for capturing airborne particles in the flow of air entering the particle collection chamber (240; 340) through the ends of the inlets (210; 310) by impaction of airborne particles on the first surface of the second layer; wherein the second layer comprises a plurality of outlets (230; 330) configured to extend through the second layer for transporting the flow of air therethrough out of the particle collection chamber (240; 340); the collecting device further comprising at least one liquid access port (260; 260a, 260b; 360a-360h) for filling the particle collection chamber (240; 340) with a reagent; and wherein the particle collection chamber (240; 340) comprises at least one side wall (246; 346) extending from the first layer to the second layer for defining flow of the reagent through the particle collection chamber (240; 340) when filling the particle collection chamber (240; 340), such that a first portion (248a; 348a) of the particle collection chamber (240; 340) and a second portion (248b; 348b) of the particle collection chamber (240; 340) are arranged on opposite sides of the at least one side wall (246; 346).