Sunlight is a natural disinfection method that essentially utilizes ultraviolet light from natural light sources to achieve sterilization and disinfection.
Ultraviolet light refers to invisible light with a wavelength range of 100 to 400 nm. Different wavelengths of ultraviolet light have different effects. Ultraviolet light is divided into four wavelengths: UV-A (400-320 nm), known as the melanin-producing ultraviolet light, which has pigment-attaching and photochemical effects and is also known as the chemical light; UV-B (320-275 nm), known as the erythema-producing ultraviolet light, which promotes vitamin D production and is also known as the health light; UV-C (275-200 nm), known as the germicidal ultraviolet light, which has a bactericidal effect; and UV-D (200-100 nm), known as the vacuum ultraviolet light, which is effective in producing ozone.
Ultraviolet disinfection is a physical disinfection method that doesn't kill microorganisms (bacteria, viruses, spores, and other pathogens) but rather inactivates them by depriving them of their reproductive capacity. The principle of ultraviolet disinfection is generally believed to be the use of ultraviolet C-band (UV-C) light to alter and damage the microorganism's genetic material, nucleic acids (DNA or RNA), causing mutations and altering their transcriptional properties, thereby depriving the organism of its ability to synthesize proteins and replicate. Ultraviolet disinfection primarily utilizes the C-band.
