Germicidal ultraviolet (GUV) lighting is gaining attention as a method to improve indoor air quality, with recent research shaping standards like ASHRAE 241. A March 2025 article in Facilities Dive highlights a Pacific Northwest National Laboratory (PNNL) study, which demonstrates GUV’s ability to provide equivalent clean airflow, offering an energy-efficient alternative to traditional ventilation for pathogen control in buildings.
The article focuses heavily on 222 nm far-UV light, touted for its potential to disinfect occupied spaces by inactivating pathogens like SARS-CoV-2 at low doses. However, this approach faces significant challenges. Far-UV’s effectiveness in disrupting viral RNA and DNA raises concerns about similar damage to human DNA/RNA, posing risks to vulnerable groups like cancer patients and young children. Additional drawbacks include underpowered performance requiring multiple devices per room, driving up costs, and the use of hazardous krypton-chlorine gas in excimer lamps. Wavelengths below 240 nm, including 222 nm, can also produce ozone, which may react with indoor volatile organic compounds to create harmful byproducts, further complicating its safety profile.
In contrast, the article largely overlooks in-duct UV systems, which use ultraviolet light within HVAC ducts to disinfect air without exposing occupants. This method avoids the safety issues of in-room far-UV but is underexplored in the study, possibly due to reliance on irradiance tables based on traditional mercury lamps. Advances in LED technology, operating at wavelengths above 240 nm, offer a promising alternative. These systems can deliver higher doses of UV-C light, enhancing pathogen inactivation while minimizing ozone production and eliminating the need for hazardous gases.
Organizations exploring UV solutions are beginning to recognize the potential of in-duct systems with LED technology, which prioritize safety and efficiency for air purification in settings like healthcare facilities and schools. This approach addresses the limitations of in-room far-UV, offering a sustainable path to cleaner indoor environments.
Learn more about UV applications at uv-clear.com.
Citation:
- Facilities Dive. (2025, March 6). Germicidal ultraviolet lighting disinfection indoor air quality ASHRAE 241 research PNNL. https://www.facilitiesdive.com/news/germicidal-ultraviolet-lighting-disinfection-indoor-air-quality-ashrae-241-research-PNNL/721909/
