Ultrahigh Efficacy Air Purifier for Airborne Pathogens

The COVID-19 pandemic has heightened awareness of airborne pathogens and their role in transmitting infection throughout the population. The threat of airborne pathogens extends beyond SARS-CoV-2. Diseases caused by airborne viruses (Influenza), bacteria (Legionnaires’ disease and Tuberculosis), and fungi (aspergillosis) are also prevalent, with Influenza estimated to cause 200,000–500,000 worldwide deaths annually. Additionally, airborne pathogens such as Bacillus anthracis (anthrax) present a viable bioterrorism threat. Indoor environments increase the risk of airborne disease transmission. HEPA filters are effective at removing airborne pathogens, but they come with a significant cost burden and energy penalty. While several emerging technologies have been introduced in the market, third-party validation of efficacy is either lacking or has demonstrated lower effectiveness levels under real-world test conditions than performance claimed by manufacturers. The opportunity exists to create a sustainable, energy-efficient solution to reduce airborne pathogens in indoor spaces. The Phase I project investigated the feasibility of Sonata’s photocatalytic VOC abatement platform to mitigate airborne pathogens. The project separately evaluated pathogen capture and neutralization functions in indoor environments. Inactivation rates exceeded the Phase I goal, even under the most energy efficient test conditions. When operating within the energy envelope of a typical HEPA filter (including blowers), the technology demonstrated a 3-log10 kill efficiency in 30 minutes for S. epidermidis. A 4-log10 inactivation was achieved for MS2 bacteriophage in 5 minutes. The scaled photoreactor, operating at 10 CFM, was efficient at removing 3-log10 of both S. epidermidis and MS2 bacteriophage in 30 minutes from a 1 m3 chamber. The system has a pressure drop approximately 20% of a new HEPA filter. This performance validation will be extended in Phase II, which will focus on scaling the system to 100 CFM flow rates while optimizing pathogen capture and energy efficiency. The target market is occupied commercial spaces, which includes office buildings, restaurants, hotels, health care facilities, and schools. The envisioned product is suitable for airborne antimicrobial control in existing HVAC systems as well as new equipment. The markets for air purification are large and growing strongly; the world-wide air purification market was $10.7B in 2020 and is projected to grow to $22.8B by 2028.