So long as you are far enough from a major freeway, major road, major airport, or major port. With those requirements the number of californian daycares or schools that meet that criteria shortens significantly.

It was a big thing in the early 1900s too:

https://en.wikipedia.org/wiki/Open_air_school

And it's good for your eyesight.

Yes. Lots of new results in this topic. Get outside and exercise those eyes.

Unless you don't want to expose your kids to sun screen, eeek /s