Q.What type of hedges are best for privacy?
I have a 12000 sq ft backyard,I would like to keep it free from my neighbors dust. They have a property that is all dirt.
I live in the San Gabriel valley area 91770. Please advise. Thanks

There are many possibilities for a privacy hedge in your area.
https://www.google.com/search?q=best+privacy+hedges+for+southern+california&ie=&oe=
Consider Pacific Wax Myrtle, a native plant that is beautiful and low maintenance and drought tolerant.
It's not as fast growing as privet and cherry laurel, but those are less drought tolerant and more maintenance.