In order to solve the problem of the continuous online monitoring of the fixed pollution source emission particles, on the basis of the advantages and disadvantages of the comprehensive analysis of the extinction method, the β-ray absorption method, the micro-oscillating balance method, the charge transfer method, and the light scattering method, the particle size distribution and concentration optical detection system based on aerodynamic particle size spectrometer is designed according to the Mie light scattering principle. A high-performance aerodynamic particle size spectrometer is designed using a single-wavelength method to measure the concentration of particulate matter, and the equipment and the detection system are used in the continuous monitoring of particulate matter emitted by thermal power plants and compared with the ES632 equipment. Through the system test, the results show that compared with the ES632 equipment performance, the lowest concentration measured by the design of aerodynamic particle size spectrometer equipment can reach 0.1 mg/m3 with a measurement accuracy of 0.01 mg/m3. Compared with the ES632 equipment, the measurement concentration value is 8% higher, which meets the test requirements.

Particle mass and particulate size are two important parameters used to characterize the aerosol. Currently, there are a few methods for measuring particle mass concentration and particle size. However, the existing methods have their own shortcomings. In this article, we describe a novel laser scattering instrument that measures mass concentration and particle size in real time over a wide concentration range. This instrument combines laser scattering and time-of-flight aerodynamics in one optical device. There are two innovations in this paper: (1) Two APD detectors are used to receive scattered light. One receives forward-scattered light and the other receives side-scattered light. The advantage is that the sensitivity of the detector is increased greatly, and the ratio of forward and side scattering is used to further obtain the size and shape information of the particles. (2) In order to measure the high concentrations of aerosol, a high-speed ADC and FPGA is combined to achieve an anti-overlap algorithm objective. It has been verified by experiments that the anti-overlapping algorithm can effectively improve the applicability of the aerodynamic particle size spectrometer under high concentration conditions.