How does Ultraviolet Germicidal Irradiation (UVGI) function?

Ultraviolet Germicidal Irradiation (UVGI) operates primarily through its ability to disrupt the DNA or RNA of microorganisms, including bacteria and viruses. When these microorganisms absorb UVGI energy, the high-energy photons cause the formation of thymine dimers in the DNA. This abnormal binding prevents the normal replication of the organism, rendering it inactive or non-viable. As a result, UVGI is effective in sterilizing air and surfaces by inactivating pathogens, making it a valuable technology in improving indoor air quality and preventing the spread of infectious diseases.

The other options do not accurately describe the mechanism of UVGI. Purifying the air by filtering particles involves physical removal rather than disinfection. Cooling the air to eliminate bacteria does not involve UVGI, which is purely a disinfection method and does not have a cooling effect. Ionizing the air typically refers to a different process which generates charged particles, but this is not how UVGI achieves its germicidal effects. Thus, the effectiveness of UVGI in inactivating microorganisms is what distinguishes this method.