May 12, 2020

Efficiency of disinfection and droplet size


The droplet size of spraying equipment has a significant effect on the efficiency of virus control. Therefore, we’ve conducted an internal analysis to explain the relationship between the efficiency of disinfection and droplet size.

Why is a smaller droplet size more efficient for disinfection?

It all depends on the method of disinfection to fight airborne viruses or surface-adhering viruses.

Infection route

First of all, we need to understand the difference between the transmission of a floating virus and surface-adhering virus.

  • Floating virus: defined as airborne contamination, it happens when someone is sneezing or coughing without covering its mouth. Therefore, the infection occurs while breathing.
  • Surface-adhering virus: defined as cell-to-cell contact infection. It happens when a contaminated object gets in contact with a human body (a handshake). If the person touches its face, there can be a mucus infection.

Research has shown that fine particles of contaminated particles are still floating in the air up to 20 minutes after a patient has coughed. Therefore, it is recommended to disinfect not only objects but also the surrounding air. This way you can avoid both surface-adhering viruses and floating viruses.



Efficiency of disinfection and droplet size

In order to fully disinfect a room and its objects, and simultaneously fight floating and surface-adhering viruses, we recommend a more intensive and efficient method by spraying what we call “Dry Fog”.

What is Dry Fog?

Dry Fog is a fine fog with an average droplet size of 7.5 μm that doesn’t wet the environment and the objects.

Due to its small size, the droplet evaporates in the air before reaching any surface, therefore, not wetting.

We have several successful installations and proven experience in using Dry Fog for humidification purposes. In several industries from electronics and semiconductor fabrication plants to similar production facilities where strict humidification restrictions exist.

IKEUCHI's classification of droplet size

Creating Dry Fog can be done by using a lot of air to break down the water droplets (high pressure systems), but that way is neither economical nor environmentally friendly.

Our AKIJet series and AKIMist® humidifier are the best atomizing technology that can efficiently generate Dry Fog with as little energy as possible.

droplet size

How efficient is a small droplet for disinfection?

Our patented nozzles AKIJet series and humidifier AKIMist® are characterized by the extremely small and uniform-size spray droplets.

  • Dry Fog droplet size: is on average 10 μm
  • COVID-19 virus: is about 0.1 μm in size and often appears in clusters measuring 5~10 μm
  • If the disinfective droplets are too big and there’s too much disinfectant liquid, then it becomes corrosive for the spraying unit, the environment with equipment and the human body = a droplet size around 5~10 μm is the best

IKEUCHI’s Dry Fog technology can generate about 250,000 fog droplets per second.

This means, that our Dry Fog roughly generates 60,000 times more particles than virus-sized droplets.

For contaminated clusters of about 5 μm: If a large amount of Dry Fog of 0 to 20 μm can be generated, it can be said that the probability of contact with the cluster becomes very high.

disinfection and droplet size

The Dry Fog can saturate a room up to 100% relative humidity (RH) without ventilation. One AKIJet series nozzle (03C type) is suitable for spaces of 100 m3 (without ventilation), covering a distance of 4 m from the nozzle.

For example, to reach 100% RH at 15℃ in a room of 100 m3:

  • From 40% RH to 100% RH: 0.9 L of water is needed to be sprayed.
  • One nozzle of AKIJet series of 03C type (humidifier AE-1(03C)) sprays 2.4 L/hr at 0.3MPa (ca. 3 bar).
  • Therefore, with one AKIJet series nozzle, the relative humidity level will reach 100% in about half an hour.

For an efficient spatial disinfection, please follow the guidelines of fogging time and disinfectant liquid consumption from the chemical liquid provider. 

Advantages of Dry Fog for spatial disinfection

  • Cost effective method as no need for manpower (no wiping needed).
  • Used in critical spaces without the presence of operators thanks to the portable format.
  • Highly efficient spraying unit that rapidly and safely deliver an even fog disinfection.
  • Fog sanitation reduce the numbers or airborne micro-organisms.
  • 100% coverage as whole room disinfection allows thorough disinfection of difficult-to-reach places (where sprays and wipes can’t reach), as well as all exposed room surfaces such as ceilings, walls, floors and equipment.
  • Fast spreading of the fog disinfection in a room without wetting.
  • Fog sanitation is a proven method to fight against micro-organisms infections in the food industry for example (Source: Cleanroom Technology).
  • Prevent the risk of cross-contamination with surface-adhering virus and the risk of re-contamination.
  • Safe to use around sensitive electronic equipment thanks to its non-wetting characteristic.

Our disinfection units

For spatial disinfection and contact infection prevention, we offer different type of atomizing technologies.

Have a look to our line-up

We do not provide the disinfectant liquid. Therefore, please follow the guidelines of the disinfectant company in terms of the concentration quantity to dilute and spray, as well as the fogging time and the exposure time for the inactivation of the viruses.

As each country has its own regulation when it comes to disinfection, please respect them.

IKEUCHI fogging unit recognized as an efficient and safe disinfection unit

A study conducted in 2001 with the Osaka University Medical School concluded that IKEUCHI’s atomizing technology is suitable to disinfect ward rooms, operating theaters, and general-use rooms in hospitals.

Thanks to our experience and knowledge, our fogging disinfection unit sprays an even and uniform-size droplet fog, solving major problems hospitals were facing:

  • No danger of harm for workers through contact or inhalation thanks to the complete automation of the fogging process.
  • No damages on the sensitive medical instruments thanks to the non-wetting characteristics.
  • 100% coverage of disinfection from the ceiling to the floor, as well as walls and narrow gaps.
  • Financial benefits with reduction of labor costs due to the simple operation and shorter disinfection time.

Evaluation of an Automatic Fogging Disinfection Unit

A similar study was conducted in 2012 by the Public Health Agency of Canada which concluded that not only our fogging disinfection unit AKIMist®”E” completely inactivate all microbial agents tested, but it is compatible with electronics device. The AKIMist®”E” was used to decontaminate laboratory spaces.

Evaluation of a Dry Fogging System for Laboratory Decontamination

In Slovakia, our Dry Fog AKIMist®”E” is installed in elderly houses, hospitals, stores, offices, etc., as a mobile disinfection unit with the collaboration of RealTime Technologies to fight the spread of the current pandemic (COVID-19).

For more information about their mobile unit, click here

The Slovakian newsmedia MY Žilina covered the successful installation of the mobile disinfection unit.

Click here to read the article


If you have a question about the right spraying solution for your situation, our team of sales engineers is available to help you choose the right product. Please contact them via email.

Contact us to know more about our products.