As difficult, creepy and antagonistic as your neighbor sounds, his complaints of dust are quite likely legit. Arena dust carries a surprisingly long distance, and seeps into everything. There is both visual dust, and fine essentially invisible dust (until it builds up on surfaces). It clings to house windows and siding, settles on lawn furniture, coats your car and irritates your airways. You are not able to open your windows. If the prevailing wind floats dust in his direction it is a problem that you need to address. Gaaahhh, imaginge what he thinks when you drag the area!!! How he chooses to use his property (leaves garage door open) is up to him, and he is not required to change, it is up to you to fix the problem.
I recommend you immediately address his complaint by spreading Mag flakes, Whoa Dust or similar product in generous amounts. Since your ring is near a home, this should have been done as the project was wrapping up. If it was done, it is time to reapply. Inform the neighbor that dust reduction products have been applied. ( Personally, I would make a great visual show of the process when I was sure he was watching. Better still, spread that hour’s work into a few hours done over a couple of days) This action can happen today and will greatly reduce any dust that might travel to his property. Then plant a fast growing barrier such as Miganthus Giganteus to provide rapid reduction in wind carriage, and a much needed privacy barrier. These actions will dramatically reduce dust, are cost effective, easy and FAST.
Long term you can look at a more permanent and pretty privacy/dust screen and installation of a watering system.
Again, I agree, not the neighbor I would want, but also not ok to discount his complaint.