Saw truck spraying fog/Aerosols into air

Last night at almost 1am I saw a truck spraying fog/aeresol in my neighborhood.

I opened my front door to enjoy the cold air and I watched a white truck with writing on it drive past fairly quickly. It had a large canister on the back that was dispensing a fog or aerosol. I could see the "steam" or whatever it was vaporizing up into the air.

I wasn't able to catch any words on the pickup truck but it did have a few lights on the back of the cab flashing orange.

Is this for mosquitos? Or something else? 👀

Area: nearish i-17 and bell rd exit/entrance. In the neighborhood at 12:53am.

Tried to post on r/phoenix but mods removed my post