Related Clues:
- UV ray absorber
- ___ hole
- Triatomic molecule
- Gas that both protects and pollutes
- Swamp gas, essentially
- Firedamp, for the most part
- Depleted layer
- Invigorating seaside air
- Atmospheric layer in some danger
- Invigorating air at seaside
- Invigorating air at the seaside
- Kind of oxygen layer in atmosphere, has hole in it
- Form of oxygen in earth's upper atmosphere - there's a hole in it
- Layer that protects against ultraviolet rays
- Oh, three round the region!