How do propane mosquito traps kill the mosquitoes?

Propane mosquito traps use gases Octenol and CO2 to attract the insects. After they are drawn closer, the propane traps suck them dry. They have in-built fans which pull the mosquitoes inside. Once they are inside, they can't escape. After they get dehydrated, either they get too weak to fly or just die there. Because of this effective method of killing, the propane mosquito traps are considered the most efficient mosquito killers.