Smog Over New York . ... Credit Copyright: STS-92 Crew , NASA Explanation: What is not pretty about the above picture ? In a word: smog . ... Between the clouds at the top and ground at the bottom, however, is a trapped layer of smog. ... As opposed to " good smog " in the upper atmosphere, "bad smog" near the ground is created mostly by humans. In the upper atmosphere, ozone reflects back harmful ultraviolet radiation , but when it occurs near the ground, it can be inhaled. ...