I had been wondering if the town did any arial mosquitoes control. Indeed, it does.
"Bti is virtually non-toxic to humans, plants, and animals. The Bti is impregnated on coarsely ground corncob granules. In the larger wetlands which are inaccessible from roads, these applications will be done by helicopters flying at tree top level. The granules, when applied, fall straight into the wetland and do not drift beyond the targeted area."
"Bti (Bacillus thuringiensis israelensis), a naturally occurring soil bacterium that kills mosquito larvae before they become adult mosquitoes."