An impactor inlet for a system for monitoring an aerosol including a plurality of particles is provided. Each of the particles has a size. The inlet includes a housing defining a chamber to receive and direct a flow of the aerosol. A high flow rate nozzle receives the aerosol at a flow rate of greater than 20 liters per minute (lpm) and accelerates and directs the aerosol flow toward a impaction plate. The aerosol flow separates into a minor flow including particles having a size greater than about 10 um, and a major flow including the remaining particles. The minor flow impacts on the impaction plate, and the major flow is emitted from an outlet.