Great news! A good chemical-free way to prevent mosquitoes from bothering you when sitting outside is to just set up a fan nearby and turn it on. Mosquitos are weak flyers and this will keep them away.
The head guy in the fight against mosquitos and West Nile Virus in NYC (Dr. Bajwa, a medical entomologist) turns on a pedestal fan when sitting outside his home. No chemicals needed!
Bottom line: Using a fan can ward off mosquitoes. People differ in the types of fans they like to use (oscillating fan, stationary fan, ceiling fan). By the way, a breezy or windy day is also great in keeping mosquitos away.
From the NY Times: In a Decaying Queens Fortress, It’s One Man Versus 47 Kinds of Mosquito
He has his own method of dealing with mosquitoes. “When I find myself relaxing in my backyard, I always set up a pedestal fan,” he wrote. “Mosquitoes happen to be weak fliers, unable to contend with even a gentle breeze.” When he does get bitten, he added, “I make a conscious effort not to give in to the temptation of scratching.”
The NY Times wrote about this method already back in 2010: The Claim: To Repel Mosquitoes, Use a House Fan ...continue reading "Wind From A Fan Can Keep Mosquitoes Away"