We as humans naturally exhale carbon dioxide when we breathe and when mosquitoes are around the mosquitoes are attracted to the carbon dioxide that we exhale.
Mosquitoes can also be attracted to chemicals that we sweat out and also be attracted to certain blood types.
You can eat garlic to keep mosquitoes away from you or wear a clove of garlic around your neck to naturally repel mosquitoes.
I also recommend a mosquito trap that runs off of propane to suck of the mosquitoes and kill them.