A chemical weapons expert involved in the apparent discovery of continued chemical weapons attacks in Syria told ITV News earlier this week that chlorine use is "simple to identify".
Hamish De Bretton-Gordon told Diplomatic Correspondent John Ray that Syrians should be armed with information on how to identify such attacks.
He added, however: "It's very, very non-persistent - once it's released it will remain active for, at the most, minutes.
"If there is a strong wind and if it is hot as it is in Syria it will disappear very quickly."
More top news
It has been confirmed that the 2015 world tour of top Gear Live will go ahead, renamed Clarkson, Hammond and May Live.
A new ITV news/ComRes poll in Scotland suggests there is serious trouble ahead for Labour.
Two gangs of warring criminals are behind a string of violent gun, knife and grenade attacks in Greater Manchester, police have revealed.