My question is, does grounding work whenever I am walking on concrete/grass/dirt/sand despite what is underneath that substance? When I think of the grass in a park or on my lawn, I feel like beneath all the grass and dirt - there are things which might disrupt the conductivity - like man made things such as pipes, concrete, empty air spaces where wires and pipes go. I wouldn't worry at all about that, the main thing is that you're skin is touching the ground. Any pipes run underground under the grass won't make a bit of difference and the wire has to be in pipe too so that's not a worry. On top of any pipe run underground is dirt/earth ;-) I don't know what might be under sand except earth lol! They say that concrete is conductive too.
Also, I am also worried about getting parasites from walking on grass. On my lawn I don't worry as much. But at a park or other public places I feel like I could be stepping in a place where a dog previously took a dump and exposing myself to diseases. The only time I would be concerned about that is if I had an open wound on my foot, other than that, no worries. You're feet are washable lol.
I live in California - where the weather is sunny right now. Should I be worried about these things? I guess I could just put on a pair of socks but from I understand barefoot is probably better. I wouldn't be worried about any of it, not one little bit! Get those footsies on the earth and you'll get rid of all that static electricity and you'll get the negative electrons that your body so badly needs.