PM2.5 detection assembly and PM2.5 sensor

The utility model relates to a PM2.5 detection subassembly and PM2.5 sensor, PM2.5 detection subassembly includes printed circuit board, laser module and fan, also include air duct casing, air duct casing buckle fixed on printed circuit board, air exhaust air duct is formed inside air duct casing, also integrated connection is annular fan seat on the air duct casing, and the air duct casing buckle fixed on the printed circuit board. An inner hole of an annular fan seat is communicated with the air exhaust duct, a fan is installed on the fan seat, and an air inlet of the fan is right opposite to the inner hole of the fan seat. The fan base is arranged on the air duct shell, the overall size is reduced, and universality and feasibility are improved. According to the PM2.5 sensor provided by the utility model, the upper cover and the PM2.5 detection assembly as well as the upper cover and the lower cover are buckled and fixed along the vertical direction, so that the assembling process is very simple, and the as