Mosquito magnet
The CO2 emitting gadget is known as the mosquito magnet, which
... runs on liquid propane which is converted, through a catalytic reaction, into carbon dioxide and warm water vapor in similar proportions to that of human breath.
Mosquitoes don't like much wind or sun - they are flimsy little $#!ts - so avoidance of calm, cool, shadowy areas is a key to keeping the little pests at bay.
S