Air cleaner and method for controlling the air cleaner

An air cleaner comprising:

• a main body;
• a case coupled to an outer side of the main body and comprising a suction port for sucking air into the main body;
• a filter unit disposed inside the main body;
• a dust sensor for sensing dust concentration;
• a first flow path provided so that air sucked through the suction port is flown to the dust sensor;
• a first valve located on the first flow path for opening and closing the first flow path;
• a second flow path provided so that air filtered through the filter unit is flown to the dust sensor;
• and
• a second valve located on the second flow path for opening and closing the second flow path,
• a third flow path provided so that air provided to the dust sensor, through the first flow path and the second flow path, is flown to an outside of the dust sensor,
• wherein the dust sensor is further configured to sense first dust concentration of air flowing along the first flow path, the dust sensor, and the third flow path in a state where the first valve is opened and the second valve is closed and sense second dust concentration of air flowing along the second flow path, the dust sensor, and the third flow path in a state where the first valve is closed and the second valve is opened,
• wherein a front end of the first flow path in which the air sucked through the suction port is flown to the first flow path is located at a front surface of the filter unit to which the air sucked through the suction port is provided,
• wherein a front end of the second flow path in which air filtered by the filter unit is flown to the second flow path is located on a rear surface of the filter unit from which the filtered air is discharged, and
• wherein a rear end of the third flow path from which the air is discharged is located on a rear surface of the filter unit from which the filtered air is discharged from the filter unit.