Method and apparatus for determining an air quality level

An apparatus for determining an air quality level comprising;

• air quality sensing means for detecting a state of air quality;
• temperature and humidity sensing means for detecting air temperature and humidity;
• reference value output means having preliminary relational values established between different temperatures and humidities and output values of the air quality sensing means, said relational values serving as a reference air quality;
• and
• computing means connected to said air quality sensing means, said temperature and humidity sensing means and said reference value output means, for obtaining a threshold value for air quality determination upon air quality detection by amending a predetermined threshold value of an absolute determination reference of air quality level from said preliminary relational values on the basis of the detected temperature and humidity, said computing means determining air quality by comparing an output upon air quality detection of the air quality sensing means with the obtained threshold value for air quality determination upon air quality detection.

An apparatus for determining an air quality level comprising;

• air quality sensing means for detecting a state of air quality;
• temperature and humidity sensing means for detecting air temperature and humidity;
• memory means for storing threshold values that provide an absolute determination reference of air quality level, a first output value indicative of a clean state of the air quality sensing means as a condition of temperature and humidity under which the threshold values are derived and a formula for an output value of the air quality sensing means that is correlated with various values of temperature and humidity;
• correction means for computing a second output value t indicative of a clean state of the air quality sensing means on the basis of temperature and humidity detected by the temperature and humidity sensing means during air quality detection by using said formula, calculating and taking as an output correction amount a difference between the second output value and the first output value, and correcting a threshold value for air quality level determination by adding the correction amount to the threshold value for air quality level determination;
• and
• computing means for determining an air quality level by comparing the corrected threshold value for air quality level determination by the correction means with an output of said air quality sensing means, and outputting a control signal for controlling an air quality regulator.