OZONE

Stratospheric layer of gas — invigorating sea air (5)

Solution has appeared in 4 crosswords (3 across and 1 down):

• Quick crossword No 16,259 — 2022-06-16 23:00:06
  20A: <span>Colourless gas, O</span>₃ (5)
• Quick crossword No 15,612 — 2020-05-20 23:00:39
  23A: Atmospheric gas shielding us from ultraviolet radiation (5)
• Quick crossword No 15,471 — 2019-12-07 00:00:01
  2D: <span>Colourless gas, O</span>₃ (5)
• Quick crossword No 15,233 — 2019-03-05 00:00:34
  11A: Stratospheric layer of gas — invigorating sea air (5)