A flow sensor housing, comprising: an inlet flow port; a flow sensing region; an outlet flow port; a flow channel extending between the inlet flow port, the flow sensing region and the outlet flow port, the flow channel defining a flow path between the inlet flow port and the flow sensing region that is contorted in three-dimensions wherein the flow path includes: a first flow channel region configured to receive a fluid from the inlet flow port along a Y axis, a second flow channel region configured to accept the fluid from the first flow channel region along an X-axis of an X-Y-Z coordinate system, wherein the second flow channel region have a greater volume or a greater cross-sectional area than the first flow channel region so as to decelerate the fluid to release particles present in the fluid stream, a particulate matter collection region included in the second flow channel region for collecting particles released as the fluid passes from the first flow channel region to the second flow channel region, wherein the particulate matter collection region is located in a bottom portion of the second flow channel region, characterised in that: the second flow channel region is further configured so that the fluid continues to flow downstream towards the flow sensing region by exiting the second flow channel region along a Z-axis of the X-Y-Z coordinate system. an inlet flow port; a flow sensing region; an outlet flow port; a flow channel extending between the inlet flow port, the flow sensing region and the outlet flow port, the flow channel defining a flow path between the inlet flow port and the flow sensing region that is contorted in three-dimensions wherein the flow path includes: a first flow channel region configured to receive a fluid from the inlet flow port along a Y axis, a second flow channel region configured to accept the fluid from the first flow channel region along an X-axis of an X-Y-Z coordinate system, wherein the second flow channel region have a greater volume or a greater cross-sectional area than the first flow channel region so as to decelerate the fluid to release particles present in the fluid stream, a particulate matter collection region included in the second flow channel region for collecting particles released as the fluid passes from the first flow channel region to the second flow channel region, wherein the particulate matter collection region is located in a bottom portion of the second flow channel region, characterised in that: the second flow channel region is further configured so that the fluid continues to flow downstream towards the flow sensing region by exiting the second flow channel region along a Z-axis of the X-Y-Z coordinate system. a first flow channel region configured to receive a fluid from the inlet flow port along a Y axis, a second flow channel region configured to accept the fluid from the first flow channel region along an X-axis of an X-Y-Z coordinate system, wherein the second flow channel region have a greater volume or a greater cross-sectional area than the first flow channel region so as to decelerate the fluid to release particles present in the fluid stream, a particulate matter collection region included in the second flow channel region for collecting particles released as the fluid passes from the first flow channel region to the second flow channel region, wherein the particulate matter collection region is located in a bottom portion of the second flow channel region, characterised in that: the second flow channel region is further configured so that the fluid continues to flow downstream towards the flow sensing region by exiting the second flow channel region along a Z-axis of the X-Y-Z coordinate system.