"If you make bombs at home, particles leak into the air and you might flush things down the toilet, so we are simply trying to find these chemicals and then trace their origin, " research head Henric Östmark at the Swedish Defence Research Agency (Totalförsvarets forskningsinstitut – FOI) told The Local on Thursday.
The upcoming technology will not be put to use randomly, but rather help the police and security services home in on suspects. Such a sniffer could have helped neighbouring Norway, for example, to gather forensic evidence against terrorist Anders Behring Breivik before his murder spree in 2011.
"If you make a bomb out of fertilizer you have to grind it and it's incredibly messy," Östmark explained. "He wrote in his manifesto how difficult it was. In that case you could have detected particles on door handles and window sills."
A handful of researchers at FOI have worked on the European Commission-funded project alongside British, Dutch and German partners. For the Brits, in particular, an early detection system could have helped the police in their efforts to stop the 2005 London attacks.
"The sniffer would complement intelligence reports into terror activities," Östmark said, explaining that in some cases sensors could be put up to detect relevant chemicals in the air. "Those bombs were made in Leeds. The police knew something was going on, but didn't know how to find them."
The sniffer project has been under way for two years, with a final report and test runs due for September 2014. FOI researchers have also been looking at ways to contaminate dual-use household products to render them useless in the production of explosives.
"We've had some successful results, so we're glad," researcher Malin Kölhed told Sveriges Radio earlier this month, but underlined that attempt to neutralize the products would never be totally foolproof. "We can make it much more difficult, so that's what we're focusing on."
FOI has also looked into how to make sure forensic evidence is collected properly at the scene of an attack.
"It's all part and parcel of making society safer," Östmark told The Local. "We have to tackle the bomb factories, it will just get worse and worse. The Anarchist Cookbook and much worse is out there on the internet."