The BLSG Insect Control District sprays pesticides along town roads to kill adult mosquitoes. The most recent public notice from the District identifies the pesticides as “malathion or synthetic pyrethroid insecticides.” Permethrin is the most commonly used synthetic pyrethroid. It is considered to be much less toxic to humans than malathion, and is sometimes less effective for controlling mosquitoes.
The equipment used by the BLSG to spray permethrin produces tiny droplets so a very small amount of chemical is needed. Nonetheless, permethrin is toxic to organisms other than mosquitoes. A factsheet on permethrin from the group Beyond Pesticides includes human health precautions about cancer, immune system effects, and effects on reproduction. Here is a link to the fact sheet which includes citations of the studies on which it is based: https://beyondpesticides.org/…/pe…/factsheets/permethrin.pdf
