MEASURING DEVICE FOR CONTINUOUSLY MONITORING AEROSOL AND METHOD THEREFOR

摘要

A method and instrument for continuous monitoring of an aerosol as the sulfur content of atmospheric aerosols. The instrument has an electrostatic precipitator that is turned off and on at a given frequency to modulate the particle concentration of aerosol flowing through the precipitator. A total sulfur flame photometric detector sensitive to both gaseous and particulate sulfur receives a sample of the modulated aerosol from the precipitator. The modulated particle concentration of the aerosol supplied to the detector causes a fluctuating component in the detector output that is directly related to the sulfur particle concentration. This component is amplified by a frequency and phase sensitive lock-in amplifier tuned to the precipitator modulation frequency. The resulting output signal gives a continuous measure of the sulfur particle concentration entering the instrument.