Reliability of the results of measurements of air pollution by solid particles by the method of detection of scattered laser radiation

Abstract

The problem of measuring the parameters of dust particles in the environment is currently relevant for residents of densely populated cities. Measurements of the size and size distribution function of dust particles are carried out using instruments based on the method of scattering of laser radiation. The analysis of the measurement method based on the spherical particle model and the theory of Mie diffraction is performed. The possibility of erroneous indication of measurement results by widely used portable measuring instruments of dust parameters is shown. To calculate the scattering luminous flux by particles with a size of 2–10 μm in laser radiation, a special program was developed in the Matlab medium. As a result of solving a system of linear non-homogeneous algebraic equations, the particle size distribution function is to be estimated under the condition that the intensity of the scattered laser radiation is measured by at least two fixed scattering angles. For the experimental estimation of this distribution function, four simple photodetectors were used for different fixed scattering angles.