In the future, vehicles which routinely drive round residential areas may be used to detect the manufacture of homemade bombs. Sensors fitted to police and postal delivery vehicles may become part of everyday life.

It began as a discussion between FOI and the company Portendo. The problem was the detection of explosives. Portendo was mostly concerned with the detection of actual explosives while FOI wished to go one step further and detect the substances used to make them. These thoughts have now developed into an EU project, Lotus, in which there are eight participants with Sara Wallin from FOI as project manager.

The background to this lies in the unpalatable fact that it is easy to make bombs using everyday chemicals. The substances concerned can be “cooked  up” at home in the kitchen. But even though it may be easy to make bombs, it is more difficult to conceal the traces of bomb-making.

“ The London bombs were made in Leeds. Our interest was awakened when we heard that the bomb factory’s neighbours had complained about the smell. Flowers and foliage wilted and are said to have recovered only this year. The leaves faded, and that comes as no surprise since it was bleach that was being ‘cooked’.”

The idea is now that it should be possible to monitor the air in urban areas for harmless substances as a matter of routine. Or more precisely, to check for deviations from the normal pattern. If in the street there is suddenly the smell of acetone, this could perhaps be a wake-up call.

“Within the project three different types of sensor are being developed. Portendo’s sensor is designed to be able to take all substances so as to give a chemical “fingerprint” of what the surrounding air contains. Then it is a question of whether that fingerprint is in the “library”. The other sensors are developments based on proven technology. The sensors can be located in vehicles that routinely move around the area. These could be police cars, postal delivery vehicles or, as in England, milk floats. The sensor data is transmitted via a network to a central point where the data is analysed. If there is a pattern of alerts from a particular area, it may be time for the next step.”

The project is due to start early next year and will conclude with trials in a major European city.

“And of course we do not yet know whether this idea will hold up in practice. It may be that the city environment is so complex that it will not work. We do not know how substances spread in a city environment. FOI and our Netherlands counterpart, TNO, will be studying these phenomena and developing computer models.”

Among those following the project with interest are the Swedish and German police.