A device for collecting aerosol particles in an exhaled airflow, said device comprising: - a housing having a length in a longitudinal extension direction between a first end with an inlet arranged to receive an exhaled airflow and a second end with an outlet arranged to transmit the exhaled airflow, an inner cross section defined by one or more inner walls of the housing, wherein said cross section is circular or rectangular with a transverse width (d), and wherein said housing has an elongated shape; and - at least four first type partition walls, arranged at a distance (x) from each other and extending in a direction essentially perpendicular to the one or more inner walls, partly covering the inner cross section of the housing, wherein said first type partition walls protrude from opposite sides of the one or more inner walls of the housing creating opposite openings (4a, 4b) with an opening area between the first type partition walls and the respective opposite inner wall of the housing, whereby said first type partition walls are arranged to create a labyrinth-shaped flow path having a cross-sectional flow area from said inlet to said outlet, said first type partition walls being arranged to divert the exhaled airflow from the inlet towards the outlet in a direction parallel to the first type partition walls towards the opposite inner wall of the housing, such that aerosol particles in the exhaled airflow collide with the first type partition walls and/or the inner walls and attach on the device, wherein the distance (x) between two opposite first type partition walls is smaller than the transverse width (d) of the cross section, characterised in that said housing comprises at least one second type partition wall arranged essentially parallel to the longitudinal extension direction of the housing. - a housing having a length in a longitudinal extension direction between a first end with an inlet arranged to receive an exhaled airflow and a second end with an outlet arranged to transmit the exhaled airflow, an inner cross section defined by one or more inner walls of the housing, wherein said cross section is circular or rectangular with a transverse width (d), and wherein said housing has an elongated shape; and - at least four first type partition walls, arranged at a distance (x) from each other and extending in a direction essentially perpendicular to the one or more inner walls, partly covering the inner cross section of the housing, wherein said first type partition walls protrude from opposite sides of the one or more inner walls of the housing creating opposite openings (4a, 4b) with an opening area between the first type partition walls and the respective opposite inner wall of the housing, whereby said first type partition walls are arranged to create a labyrinth-shaped flow path having a cross-sectional flow area from said inlet to said outlet, said first type partition walls being arranged to divert the exhaled airflow from the inlet towards the outlet in a direction parallel to the first type partition walls towards the opposite inner wall of the housing, such that aerosol particles in the exhaled airflow collide with the first type partition walls and/or the inner walls and attach on the device, wherein the distance (x) between two opposite first type partition walls is smaller than the transverse width (d) of the cross section, characterised in that said housing comprises at least one second type partition wall arranged essentially parallel to the longitudinal extension direction of the housing.