It is working well!
The dust (Clean up/vacuum you room!
is tell-tale evidence that the fan is blowing cool air across the cooling fins and then that air is blowing across the mobo capicators/VRMs before being expelled. That is the way they work! You do not want the fan 'sucking' air from across the hot VRMs, then through the cooling fins of the CPU cooler as the air would not be a cool as it should.
The solution would be for you to lift your case off the floor a bit (put it on a stand or on bricks) and for you to regularly clean the room to minimise dust accumulation.