What, you expect your city to sell pesticides at the city hall gift shop? You haven't researched local treatment availability very hard. Big box stores carry a Bayer Advanced tree imidacloprid and clothianidin treatment. Local small-business nurseries also carry products. You can find dozens of products for public sale online that will arrive in a few days. From my knowledge, emamectin is the only popular emerald ash borer pesticide requiring a license.

If I had a beautifully matured 70' ash with the ash borer advancing, I would gladly pay an arborist $500+ to properly treat the tree. They have the license for the good stuff and expertise to successfully protect the tree and my property value. It cost me $1,800 to have a dead 30' silver maple removed and $800 for a 10' replacement, not to mention what I lost in value. I imagine a 70' could run $5K+. When your ash dies because you didn't treat it properly, have fun with the remove/replace bill, all to save you a few hundred dollars.