15/05/2020
What's the difference between "fogging" and "spraying" of disinfectant? 🦠🔫
The quick answer is: With ANY application of disinfectant liquid the overriding factor is 'wet dwell time'. Fog generally does not make surfaces very wet, therefore it needs to be present consistently for significantly longer periods of time in order to disinfect.
You will also encounter terms such as "misting", "aerosol", “vapour” etc. Every disinfectant liquid product has varying killing properties for varying viruses, bacteria and fungi - and how much wet dwell time is required to reach an acceptable level of disinfection. Actual ‘wet dwell time’ typically ranges from 1-10 minutes, on hard surfaces, for typical disinfectant liquids.
What you spray matters as well as how it is sprayed. The type of surface matters too.
Because fog has small micron size particles (the EPA describes "fog" as anywhere between 2 and 70 microns, and "mist" as under 100 microns) it floats longer and can get in and around areas which would otherwise not be reachable. Floating fog can get “pushed” by more oncoming fog. Fogging systems for hospital rooms, for example, typically run for 3-5 [1] hours to reach desired sterilization levels.
Electrostatic type sprayers can take on the “wrap around” effect of fogging as far as getting into hard to reach surfaces. Droplets hold their cationic charge for 2-3 seconds on surfaces - resisting each other to spread evenly, and reducing dripping.
For airborne germs a disinfectant will diminish the germ it contacts midair, however which particles connect with which germs can be affected by the density and presence of the fog (or mist, or aerosol) itself. You need to consider environmental factors such as wind, temperature and humidity which affect how fog lingers.
But again, with ‘fog’ you are looking at hours of time, not minutes, to properly disinfect surfaces.
When it comes to porous materials - such as fabric - unless you soak disinfectant into the materials the disinfectant is only reaching the visible surface. Generally, laundering is considered good hygiene for fabrics. Add disinfectants to the laundering process if a more aggressive level of disinfection is needed.
The CDC is still unconfirmed on the use of high-heat steam to kill germs - not because high heat doesn’t kill germs (it does), but the steam entering the interior of your sofa, for example, may not be very hot once it gets in there. It’s unpredictable.
One anomaly to consider is: “Quat Binding”. Quats (or quaternary ammonium) is a common ingredient found in popular disinfectants. Quats will bind, or lose their potency, when you apply them to fabric - especially microfiber. Another reason it’s a good practice to spray disinfectants directly on surfaces and let them dwell wet.
Keep in mind - quats are toxic to humans, and there are a few non-toxic disinfection alternatives. Low micron particles which linger in the air are more likely to be breathed in. Be sure you are only breathing in body-friendly products.
Generally, you should consider each surface in a space, and even the air itself, for how susceptible it is to gathering or holding germs. Common points touched by hands or shoes that have been worn outside are obvious ones. If air circulation is poor germs will hang out longer. Since germs can be transferred through bodily fluids such as f***s and saliva - or be foodborne - areas such as bathrooms and kitchens need extra attention. All this considered, if someone sneezes they can send droplets quite far which could land on any exposed surface.
Diligence in regular disinfection and a practical approach to what areas are most susceptible will go a long way towards minimizing the transfer or illness.
