Whatever is in the air settles down on surfaces and creates contact points for hands. This air-surface-hand loop needs to be closed once and for all for effective infection control, writes Dilip Patil, Managing Partner, Trivector Biomed LLP, which uses cold-plasma technology to deliver microbe-free air to indoor spaces.
Conventional cleaning methods like handwashing, surface cleaning, fumigation etc. are aimed more at removing impurities from surfaces, and are point-in-time (temporary) solutions. Traditionally, air cleaning has been given lower priority, but Covid has forced us to look at it in a totally new light.
Air vents and the ‘black fungus’
The higher incidence of mucormycosis, especially during the second wave of the pandemic, was attributed to contaminated oxygen and water besides overuse of steroids, and to patients predisposed by diabetes to develop opportunistic infections. However, a recent study conducted by PGIMER (Dr Arunaloke Chakraborty) has found a high possibility that fungal spores spread through air-conditioning vents of hospitals in India.
The study further found fungal spores in 11% of samples collected from AC vents which could be directly correlated with high numbers of mucormycosis cases in surveyed hospitals. These fungal spores and tiny viruses can escape through HVAC systems and get lodged for longer duration in remote corners or hidden spaces in the room.
Dead zones and deadly germs
Another study conducted by IIT-B (Prof Krishnendu Sinha) with the help of computer simulation concluded that in ‘dead’ zones, air gets trapped, moves in a circular motion and does not get replaced with fresh air as quickly as other parts of the room. Chances of infection are higher in these dead zones, as infectious aerosols can linger up to 10 times longer as compared with other parts of the room.
Existing air-purification methods, though effective, have their own limitations and are not adequate to quickly disinfect the rooms, especially the dead zones. The effectiveness of these technologies can be enhanced by adding new-age solutions which can actively clean the surfaces and air, even in occupied spaces. A few technologies are already being used to quickly and continuously disinfect indoor air and surfaces e.g. portable in-room air-purifiers, UV lights, fumigators. But they cannot be used widely because of their harmful by-products and ill effects on human-health, besides the diminishing returns they normally provide.
Not all UV is good UV
Using handheld UV-C wands and UV-C based gadgets could be another solution for cleaning air, surfaces and dead spaces. However UV-C (at 254+ nm) has to be used carefully, as exposure to UV-C is known to be harmful for skin, eyes and electronic gadgets.
FAR UV-C (at 222 nm) however does not penetrate the outer layer of skin or eyes and these Krypton-Chlorine based excimer lamps (with optical filters) have been widely studied and extensively used to prove their safety and efficacy, including on live SARS-CoV-2. These FAR UV-C lamps promise to be the most sustainable, safe and effective solution for surface and air-disinfection of occupied indoor spaces, especially in the post-pandemic environment.