Shedding Light on the Unseen Effects of UV-C Disinfection

As the world grappled with the COVID-19 pandemic, there was a growing interest in finding effective methods to halt the spread of the virus. One such method that gained prominence is Ultraviolet Germicidal Irradiation (UVGI), which employs UV-C radiation to deactivate viruses and bacteria. UVGI has been a trusted tool in hospitals for decades, used to sterilize both air and surfaces. But a recent study has uncovered some intriguing findings about the unintended consequences of UVGI on indoor air quality (IAQ). In this blog post, we’ll break down the key takeaways from this study, explaining the impact of UVGI devices on the air we breathe.

The Basics of UVGI:
UVGI works by using high-energy UV-C radiation to break the molecular bonds of pathogens, rendering them inactive. This method has been especially valuable in healthcare settings. However, when UV-C radiation interacts with non-pathogenic molecules in the air, it can lead to unexpected outcomes.

The Study’s Objective:
The study in question aimed to investigate how a commercial high-intensity UV-C disinfection device, with a power of around 2 kW, affects the composition and concentration of gases and particles in indoor air. This research focused on UV-C radiation at a wavelength of 254 nm, which is commonly used in UVGI devices.

Surprising Findings:
The results were eye-opening. When the high-intensity UV-C lamps were turned on, several significant changes occurred in the indoor environment.


  • Particle Formation: A substantial increase in the concentration of small airborne particles was observed whenever the UV-C lights were activated. These particles could have implications for indoor air quality and, consequently, human health.
  • Gas Phase Changes: Almost all of the monitored gas phase species showed an increase in concentration during UV-C exposure. This suggests that UV-C radiation can have a considerable impact on the chemistry of indoor air.


Implications for IAQ:
The study raises concerns about the effects of UVGI devices on indoor air quality, particularly when used in occupied rooms. The high-intensity UVGI device studied here was intended for short durations in unoccupied spaces. However, lower-intensity UVGI devices, designed for continuous use in occupied rooms, are also prevalent. The potential IAQ effects of these lower-intensity devices are still largely unexplored and warrant further investigation.

Ventilation Matters:
One important factor that can mitigate the impact of UVGI on indoor air is ventilation. A more effective HVAC system and increased ventilation rates can help reduce the concentration of UVGI-produced air pollutants more rapidly. This emphasizes the importance of a well-designed ventilation system in indoor spaces.

More Research Needed:
While this study provides valuable insights, there’s still much to learn about the effects of UV-C disinfection on IAQ. Factors such as the intensity and duration of UV-C exposure, ozone concentration, and the presence of volatile organic compounds (VOCs) in the room all play a role in determining the ultimate impact on indoor air.

In conclusion, the use of UVGI devices for disinfection is a powerful tool, especially in healthcare settings. However, this study reminds us that there can be unintended consequences for indoor air quality. As we continue to explore ways to keep indoor spaces safe and clean, it’s crucial to strike a balance between pathogen deactivation and potential IAQ effects. Further research will be essential in understanding the full scope of UV-C disinfection’s impact on the air we breathe.

For those eager to delve deeper into the scientific details and explore the study in its entirety, you can access the complete research paper here: Full Study

Understanding the complexities of UV-C disinfection and its effects on indoor air quality is a critical step toward creating safer and healthier indoor environments for all.

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