This is an interesting topic that is seldom discussed. I flew out of Dubai for 14 years and never wore a hat or used sun screen in Dubai.Didn't need to. I did wear a hat and used sun screen if we went to Fujairah, Oman, KSA, RSA, Oz or went off shore fishing. If you are driving on the Emirates highway look towards DXB and see the haze or look at the stars at night and you don't get the sparkle that you get elsewhere in the world. I used to notice that we would enter the top of the pollution around 8,000 feet when over the Gulf coming in for 12L