Electrical Current Pulse Sensor For Airborne Particles Detection At Single Particle Level

To develop the method of sizing airborne particle and obtaining size spectrum at single particle level is very meaningful for monitoring the dynamic change of atmospheric environment and the air quality.In this thesis, based on a review of the existing airborne particles detection technologies, two airborne particles detection methods on the strength of current pulse are studied. One method is combing with corona discharge technology and using Coulter theory, the detection system using for airborne particle detection was set up. 10μm particles were successfully detected with the help of the electrometer, and the S/N is 4-20. Meanwhile, the number of the signal pulse represents the number of particles in the sample, while the magnitude of the signal stand for the size of particle.Moreover, the other method for detecting and sizing airborne particles, based on charges transfer theory, was invented in the thesis, which achieved continuous detecting SiC particles with different sizes and other particles (Polystyrene) with similar size was achieved. A correlation between the particle size and the measured current signal was obtained. With a correlation coefficient (R2) larger than 0.9, this experimentally obtained correlation curve can be used to evaluate particle size from the measured signal in a short time. This method, with reliable principle, novel method and simple structure, can be employed by non-professional people.The particle detection methods presented in this thesis can be employed for the continuous current pulse detecting particulate matter in the atmosphere at single particle level, which not only enrich the traditional airborne particle detection technologies, but also have some reference meaning for the development of portable devices applying for the fast detection and analysis of airborne particle.