I have verrrrrrrrrry fair skin. I sunburn very easily. In Texas growing up, I could be outside about 10 minutes before I would burn in August. With sunblock, it was of course longer.
Now, however, I start burning after 5 minutes and if at 10 I blister. My skin hasn't changed at all.
I also notice when in direct sun with no wind the power of the heat is more than it was earlier. I don't mean it's hotter, but the feeling of the sun power is moreso. It's hard to describe, but I the ozone might not block as many rays naturally as it used to, the angle has changed, etc.