Light-scattering fine dust measurement apparatus

A light scattering particulate matter measuring apparatus which measures particulate matter concentration in outside air in a light scattering method, the apparatus comprising:

• a casing provided with an inlet into which outside air flows, and an outlet through which measurement air is discharged, the particulate matter concentration of the measurement air having been measured;
• an airflow passage which connects the inlet and the outlet in the casing and through which outside air moves;
• a heater disposed in the airflow passage;
• a light scattering particulate matter sensor disposed in the airflow passage to measure concentration of particulate matter of the measurement air;
• an internal temperature-humidity sensor disposed in the airflow passage to measure temperature and relative humidity of the measurement air;
• and
• a control unit configured to control power supply to the heater based on the temperature and the relative humidity measured by the internal temperature-humidity sensor,
• wherein the light scattering particulate matter measuring apparatus is configured to be mounted such that the outlet is positioned to be more elevated than the inlet,
• wherein the light scattering particulate matter measuring apparatus is configured to measure particulate matter concentration in the outside air by using convective movement of the outside air in the airflow passage based on operation of the heater,
• wherein the heater, the internal temperature-humidity sensor, the light scattering particulate matter sensor are positioned sequentially in the airflow passage from the inlet to the outlet,
• wherein the control unit is configured to control electric power of the heater based on the relative humidity measured by the internal temperature-humidity sensor in order to heat the outside air, moving to the outlet based on the convective movement, to a target temperature for reaching a predetermined target relative humidity, and
• wherein the airflow passage including the light scattering particulate matter sensor is narrower than the airflow passage including the heater and the internal temperature-humidity sensor such that the convective movement of air in the airflow passage is increased and the particulate matter concentration is more accurately measured.