def __get_correction_factor(temperature, humidity):
    """Calculates the correction factor for ambient air temperature and relative humidity
    Based on the linearization of the temperature dependency curve
    under and above 20 degrees Celsius, assuming a linear dependency on humidity,
    provided by Balk77 https://github.com/GeorgK/MQ135/pull/6/files
    0.00035  - 'CORA' Parameters to model temperature and humidity dependence
    0.02718  - 'CORB'
    1.39538  - 'CORC'
    0.0018   - 'CORD'
    -0.003333333  - 'CORE'
    -0.001923077  - 'CORF'
    1.130128205   - 'CORG'
    """
    if temperature < 20:
        return 0.00035 * temperature * temperature - 0.02718 \
               * temperature + 1.39538 - (humidity - 33.) * 0.0018
    return -0.003333333 * temperature + -0.001923077 * humidity + 1.130128205