Fogging (ULV), electrostatic spraying and UV-C are three different ways to disinfect a space, and none of them replaces manual cleaning of visibly soiled surfaces. Fogging suits rapid whole-room coverage after an outbreak; electrostatic spraying gives more even coverage of complex or curved surfaces; UV-C is a technology for terminal decontamination of an unoccupied room, not routine daily disinfection. Choosing between them depends on the risk, the site, and whether the room can be vacated.
What each method actually does
ULV (ultra-low-volume) fogging disperses an approved biocide as a very fine mist that settles across surfaces, including awkward or high areas a cloth cannot easily reach.
Electrostatic spraying gives the disinfectant droplets an electrical charge as they leave the nozzle, so they are drawn to and wrap evenly around surfaces — including the undersides and backs of complex or curved objects — rather than travelling in a straight line.
UV-C uses ultraviolet-C light, typically from a mobile "UV-C robot" or cabinet device, to inactivate microorganisms on surfaces that are directly exposed to the light. It only affects line-of-sight surfaces and needs the room to be empty of people during the cycle.
What the evidence actually says
Public health guidance issued during the COVID-19 pandemic — consistent across the WHO, the US CDC and equivalent UK health-authority advice — was clear that routine disinfectant fogging or spraying of general surfaces is not a substitute for thorough manual cleaning of visibly soiled areas, and should be used as a complement to cleaning with an approved product, not instead of it. That framing still holds for outbreak-response fogging today.
Peer-reviewed testing of electrostatic spraying has found strong disinfection performance where an appropriate disinfectant, dilution and contact time are used — one published study reported electrostatically applied hydrogen peroxide achieving a greater than 6-log reduction across vertical, horizontal and curved surfaces at a validated contact time. Its main advantage over fogging is more even, directed coverage of complex-shaped items rather than a general mist.
For UV-C, NHS England has published guidance and standards specifically for the application of UV-C devices in healthcare spaces (NHS Estates Technical Bulletin NETB 2023/01B), and reviews of clinical studies have reported reductions in surface bioburden and, in a number of studies, in healthcare-associated infection rates. The safety requirement is unavoidable: because UV-C exposure can cause eye and skin damage, devices must be shielded or used only in unoccupied spaces.
Choosing between them
For most commercial premises, thorough manual cleaning plus touch-point disinfection remains the baseline — fogging, electrostatic spraying and UV-C are add-ons for higher-risk situations (an outbreak, a contamination incident, a terminal clean before reopening) rather than a day-to-day replacement for cleaning. Which of the three you add depends on whether the room can be vacated (favours UV-C), whether the site has awkward or high surfaces (favours fogging), or whether you are treating complex-shaped equipment or vehicles (favours electrostatic spraying).
Fogging vs electrostatic spraying vs UV-C — at a glance
| Method | What it does | Best for | Bottom line |
|---|---|---|---|
| ULV Fogging | Disperses an approved biocide as a fine mist for whole-room coverage | Rapid response after an outbreak or contamination incident; awkward/high surfaces | Complements manual cleaning — never a replacement for it |
| Electrostatic Spraying | Charges disinfectant droplets so they wrap evenly around surfaces, including undersides and curves | Complex-shaped equipment, vehicles, irregular surfaces | More even coverage than fogging on awkward shapes, but still needs the correct contact time |
| UV-C | Uses ultraviolet light to inactivate microorganisms on directly exposed surfaces | Terminal clean of an unoccupied room, e.g. after a clinical outbreak or before reopening | Only reaches line-of-sight surfaces; room must be empty and the device shielded/certified |