Fig. 1. Schematic of integral turbidimeter and results of complex refractive index measurement^[21]. (a) Structure of three-wavelength integral turbidimeter; (b) changes in complex refractive index of aerosol

Fig. 2. Measurement results based on HSRL^[26]

Fig. 3. Schematic of two suspension particle detection instruments based on spatial light scattering. (a) Schematic of a measurement instrument based on single-angle scattering light of suspended particles^[27]; (b) schematic of a measurement instrument based on multi-angle scattering light of suspended particles^[28]

Fig. 4. Principle of scattering measurement of suspended particles

Fig. 5. Suspended particle measuring device based on single angle scattering polarization and its measurement results^[40].^{(a) Composition of the device; (b) results of the measurement}

Fig. 6. Suspended particle measuring device based on scattering polarization and its measurement results^[36,41]. (a) Composition of the device; (b) results of the measurement;(c) SEM images of the samples; (d) comparison of measurement results with those of optical analysis equipment

Fig. 7. Distribution of polarization center spectra and polarization indices of different samples^[63]. (a) Aerosols with different particle sizes; (b) aerosols with different absorption characteristics; (c) aerosols with different forms; (d) several aerosols with similar compositions but irregular shapes

Fig. 8. Decision tree based on artificial neural network^[69]

Fig. 9. Suspended particle concentration prediction model and results based on PCCA method^[71]

Fig. 10. Method and results of aerosol suspension particle identification based on CNN^[72]. (a) Measured signals; (b) one-dimensional convolution computation process on 4 channel time series signals with kernel size 3, stride 1; (c) recall matrix on test set; (d) precision matrix on test set