Do they have the ability to destroy seran gas without spreading it?
That is what they tried to do during the first Gulf War. They bombed all of Saddams facilities. Later on they discovered that bombing the facilities released the elements into the immediate area. In Iraq they were located out in the dessert. In Syria they are located close to residential areas. One of the bombed facilities in Iraq, was damaged so bad that the UN could not even enter the facility. They just sealed it and left it there. After the final war to remove Saddam, the facility was still there and still sealed by the UN. So the claim that WMD was not in Iraq was patently false, as every thing else that ever came out of the Oligarchies mouth. They initially left the facility sealed, then came back and found that the facility had been entered and cleaned out of its WMD. No one knows who got the stuff.
So if the US wants to continue its primary objective in the Middle East and Africa, which appears to be getting WMD into the hands of Islamic terrorists, then they will bomb his facilities by air.