The Wavelength-Based Inactivation Effects of a Light-Emitting Diode Module on Indoor Microorganisms

Area of Science:

• Microbiology
• Photochemistry
• Environmental Science

Background:

• Rising infectious disease outbreaks necessitate advanced physical-chemical control methods.
• Light-emitting diodes (LEDs) are explored for their potential in light sterilization applications.
• Understanding disinfection efficacy across different wavelengths is crucial for public health.

Purpose of the Study:

• To evaluate the sterilization effects of LED modules at various wavelengths (275, 370, 385, and 405 nm) on common indoor bacteria and mold.
• To compare the power consumption required for 99.9% sterilization across different LED wavelengths.
• To assess the practical applicability of LED sterilization, particularly visible light wavelengths, for infectious disease management.

Main Methods:

• Sterilization efficacy testing on Bacillus subtilis, Escherichia coli, Penicillium chrysogenum, and Cladosporium cladosporidides using LED modules.
• Measurement of time required for 99.9% microbial inactivation at each tested wavelength.
• Calculation and comparison of power consumption for achieving 99.9% sterilization.

Main Results:

• Sterilization effectiveness followed the order: 275 nm > 370 nm > 385 nm ≈ 405 nm.
• The 275 nm LED module exhibited the lowest power consumption for 99.9% sterilization.
• The 405 nm wavelength showed comparable or superior efficiency to 370 nm and 385 nm in terms of power consumption, with similar sterilization effects to 385 nm.

Conclusions:

• LEDs, particularly at 405 nm, show significant potential for microbial sterilization and infectious disease control.
• The 405 nm wavelength offers a dual benefit of sterilization and general lighting applicability, enhancing its utility.
• Visible light LED sterilization presents a promising, broadly applicable strategy for environmental disinfection and public health.