Related Clues:

• Thunderstorm product
• Kind of layer
• Environmentalist's concern
• See 11-Down
• See 31-Down
• What CFC's deplete
• See 34-Across
• It's a gas
• Ultraviolet Index factor
• Restaurant freebie
• Bleaching agent
• Earth protector
• Subject of environmentalist study
• See 22-Down
• Composition of an endangered layer