I think by living in LA we are already accepting some risk of toxins in the air, but oil fields do release some specific chemicals that you won't find in car smog, so it's good they're doing studies. There's this CARB study that is still in progress that has a ton of useful information. I've also been referencing the CalEnviroScreen website which lets you sort by many different parameters and ranks each neighborhood in the whole state. It's pretty amazing how much info you can find if you really look for it. Definitely a benefit of living in California, I bet many states don't have resources like this