Looks like the reporter is confusing the BLU-82 with a fuel-air explosive.
The BLU-82 does contain a semi-liquid explosive, but it is *not* "mixed with air" and it does *not* involve "igniting a mist" like the fuel-air bomb does.
The explosive is simply detonated in the bomb casing like almost any other conventional bomb -- albeit a VERY LARGE one.