Photoacoustic Spectroscopy-based Detection of Micro-particle Concentration in Atmospheric Pollution

  • Nan Zhao
Keywords: Photoacoustic spectrum; Atmospheric haze microparticles; Absorption coefficient; Absorption spectrum

Abstract

Aiming at the requirement of continuous, reliable, and low-cost real-time detection of atmospheric haze microparticle concentration, innovations in spectral application technology have been achieved. The results show that the absorption coefficient and number concentration of respirable dust are positive, and particles with different particle sizes have a certain effect on the absorption coefficient; as the particle size increases, the absorption coefficient increases. The measurement of NO₂ in the ambient atmosphere was carried out, and a 0.2 μm filter membrane was used to remove the interference of micro particles. Through different combination tests of number concentration and particle size, the relationship between the absorption coefficient of atmospheric haze microparticles and number concentration and particle size was obtained. The system is applied to the measurement of NO₂ in the ambient atmosphere, and compared with the long optical path differential absorption spectroscopy system, the results show good consistency. Applied to the measurement of respiratory microparticles, the change trend of the absorption coefficient is obtained, which can meet the real-time measurement of the absorption coefficient of atmospheric mist and haze in the state of natural suspension. The system has a simple and compact structure, low cost, and is not affected by other gases. It provides a new method for accurate detection of atmospheric haze micro-particles.

Published
2020-03-01