Possible Clues:

• About 78 percent of our atmosphere
• Constituent of four fifths of earth's atmosphere
• A gas ringtone
• Ringtone's maddening -- it dominates the atmosphere
• Explosion of neon right after leakage of hydrogen gas
• New ringtone that creates much atmosphere
• The atmosphere, mostly
• It's a gas, the strange ringtone
• Commonest atmospheric gas
• Gas, neon has grit mixed with it