Particulate measurement system

A particulate measurement system comprising:

• an ion generation section for generating ions by means of corona discharge;
• an electrification chamber for electrifying, by using the ions, at least a portion of particulates contained in a gas under measurement;
• an ion trapping section for trapping at least a portion of the ions which have not been used for the electrification of the particulates;
• a measurement signal generation circuit for generating a measurement signal which correlates with the amount of the particulates contained in the gas under measurement on the basis of a current value corresponding to a difference between the amount of the ions generated from the ion generation section and the amount of the ions captured by the ion trapping section;
• and
• a particulate amount determination section for determining the amount of the particulates contained in the gas under measurement on the basis of the measurement signal,
• the particulate measurement system being characterized by further comprising:
• a particle diameter estimation section for estimating the particle diameter of the particulates contained in the gas under measurement,
• wherein the particulate amount determination section performs correction by multiplying the measurement signal or the amount of the particulates determined from the measurement signal by a coefficient relating to a ratio between the estimated particle diameter and a reference particle diameter, and
• wherein (i) the particulate amount determination section determines, as the amount of the particulates, the mass concentration of the particulates by performing the correction in accordance with an expression of y=y0×(B/A)N, where y is the measurement signal or the mass concentration of the particulates after the correction, y0 is the measurement signal or the mass concentration of the particulates before the correction, A is the reference particle diameter, B is the estimated particle diameter, and N is an integer of 2 or greater, or
• (ii) the particulate amount determination section determines, as the amount of the particulates, the number concentration of the particulates by performing the correction in accordance with an expression of y=y0×(A/B), where y is the measurement signal or the number concentration of the particulates after the correction, y0 is the measurement signal or the number concentration of the particulates before the correction, A is the reference particle diameter, and B is the estimated particle diameter.