Fig. 1. Bioaerosol optical detection technologies and equipment widely used by scholars over world

Fig. 2. Schematic diagram of the basic principle of laser induced fluorescence technology

Fig. 3. Fluorescence microscopes^[23]. (a) Schematic diagram of transmission fluorescence microscope strcuture; (b) schematic diagram of fall-light fluorescence microscope structure

Fig. 4. Schematic diagram of multi-wavelength Raman-fluorescence lidar developed by researchers from Lanzhou University^[31]

Fig. 5. Schematic diagram of working principle of flow cytometer^[37]

Fig. 6. Schematic diagram of detection principle of ultraviolet aerodynamic particle size spectrometer (UV-APS)^[39]

Fig. 7. Detection principle and data classification method of WIBS. (a) Schematic diagram of WIBS structure^[12]; (b) schematic diagram of WIBS data result classification^[44]

Fig. 8. Schematic diagram of working principle of Rapid-E+ bioaerosol sensor

Fig. 9. Schematic diagram of detection principle of micro confocal Raman spectrometer^[60]

Fig. 10. Main detection principle of SERS^[67]

Fig. 11. Main detection principle of CARS^[67][CARS photons are generated after pump pulse (1), Stokes pump pulse (2), and probe pulse (3) interact with sample (4)]

Fig. 12. Schematic diagram of detection principle of BAMS^[76]

Fig. 13. Schematic diagram of basic principle of biological ATP autofluorescence reactions^[12]

Fig. 14. ATP bioluminescence detection of bioaerosols. (a) ATP-based bioluminescence assay for real-time detection of bioaerosols^[84]; (b) ATP-based bioluminescence assay on microfluidic chips for bacterial bioaerosols^[85］

Fig. 15. Schematic diagram of basic detection principle of LIBS^[87]