A particulate matter sensor device for detecting and/or characterising particulate matter in a flow of an aerosol sample guided through the particulate matter sensor device , comprising: - an enclosure , the enclosure comprising a flow inlet and a flow outlet , and the enclosure being arranged and configured for defining a flow channel for guiding the flow of the aerosol sample through the particulate matter sensor device from the flow inlet to the flow outlet ; - a radiation source arranged and configured to emit radiation at least partially into the flow channel for interaction of the radiation with at least some of the particulate matter in the flow of the aerosol sample; - a radiation detector arranged and configured to detect at least part of said radiation after interaction with the particulate matter; and - a flow modifying device (511, 511a, 512, 513, 514; 521) arranged closely upstream of the radiation detector and/or of the radiation source , and configured to at least locally modify the flow of the aerosol sample for reducing particulate matter precipitation onto the radiation detector and/or onto the radiation source and/or onto channel wall sections in close proximity to the radiation source and/or radiation detector , the flow modifying device (511, 511a, 512, 513, 514; 521) comprising or consisting of at least one additional flow opening for creating at least one additional flow into or from the flow channel , characterised in that the particulate matter sensor device comprises a circuit board that has one or more through-holes , the radiation detector being mounted on the circuit board , and the particulate matter sensor device is configured such that the at least one additional flow, during use, traverses the circuit board through the one or more through-holes . - an enclosure , the enclosure comprising a flow inlet and a flow outlet , and the enclosure being arranged and configured for defining a flow channel for guiding the flow of the aerosol sample through the particulate matter sensor device from the flow inlet to the flow outlet ; - a radiation source arranged and configured to emit radiation at least partially into the flow channel for interaction of the radiation with at least some of the particulate matter in the flow of the aerosol sample; - a radiation detector arranged and configured to detect at least part of said radiation after interaction with the particulate matter; and - a flow modifying device (511, 511a, 512, 513, 514; 521) arranged closely upstream of the radiation detector and/or of the radiation source , and configured to at least locally modify the flow of the aerosol sample for reducing particulate matter precipitation onto the radiation detector and/or onto the radiation source and/or onto channel wall sections in close proximity to the radiation source and/or radiation detector , the flow modifying device (511, 511a, 512, 513, 514; 521) comprising or consisting of at least one additional flow opening for creating at least one additional flow into or from the flow channel , the particulate matter sensor device comprises a circuit board that has one or more through-holes , the radiation detector being mounted on the circuit board , and the particulate matter sensor device is configured such that the at least one additional flow, during use, traverses the circuit board through the one or more through-holes . <EOS>