What is Counterfog?

COUNTERFOG is a system designed to provide a rapid response for collapsing all kind of dispersal agents. From chemical agents to Diesel particles. Jose-Luis Perez-Diaz (Ph. D.), the coordinator of this FP7 project, presented this breakthrough security system in the first scientific international conference on CBRN in Rome.

The system was mainly developed for removing CBRN agents from the air in case of a terrorist attack or accidental release. However, it can be also applied to remove contaminating particles responsible for the spread of respiratory diseases in highly polluted cities. Airborne agents smaller than 2.5 µm are particularly dangerous, as they are able to penetrate our respiratory system and even to reach the blood.

COUNTERFOG has proved to be able to wipe off the noxious small particles, spores or bacteria in a few minutes

How does COUNTERFOG work?

COUNTERFOG system uses small liquid droplets just of the right size. Professor Perez-Diaz invited the audience to imagine themselves as particles smaller than 10 µm being drawn by air flow to demonstrate what´s going on and why larger droplets are not efficient enough. “You would be like in a jam or jelly. You couldn’t move because the effect of viscosity of air prevails over any other effect”, pointed out Professor Perez-Diaz. If the liquid droplets are too big, particles will follow the flow of air and they will just flow around the water droplet without being caught. On the other hand, if liquid droplets were too small, they wouldn’t disturb the flow of air and the scattered particles would also escape. Additionally, water droplets of the exact size can also be used to hydrolyze effectively gases on the atmosphere.

This system has been demonstrated in a laboratory with surrogates and simulants through several decontamination tests. The results show a reduction of two to three orders of magnitude. Additionally, other chemical elements such as disinfectants can be added to the water droplets in order to improve the decontamination results.

The installation of this system would consist of displaying a set of nozzles in critical infrastructures, provided with something as simple as water and compressed air line. The pressure needed won´t be as high as other fire protection systems using fog. Besides, it can be also deployed in open fields in order to struggle against diesel contamination in larger areas. The system has been recently assembled on board on a truck and open field tests will take place in a few months. A few patents have been applied and it is ready to be implemented.

The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 312804.