There are two main reasons a smaller droplet size is desirable during the disinfecting process. First, the smaller the disinfectant droplets are, the better opportunity there is to agglomerate and neutralize / destroy liked sized pathogens on non-porous surfaces and in the air. Airborne pathogens would be repelled by disinfectant droplets that are much larger as shown below while FogClean droplets average 3.7 microns in size which enable them to agglomerate with similar sized pathogen droplets. Second, as droplet size decreases, the amount of surface area being treated increases using the same amount of solution. So a nozzle that creates a smaller droplet or fog will use less solution to cover a given area than a nozzle that sprays disinfectant.