Related Clues:

• Earth's ___ layer
• Protective layer makeup
• Thunderstorm byproduct
• Ultraviolet blocker
• Gas in a layer
• Atmospheric concern
• Makeup of a protective layer
• Atmosphere layer
• Layer with a hole
• A layer with a hole
• Gas used as fuel
• Thinning layer
• Fresh air
• Contents of a newsworthy layer
• Kind of hole or layer