Possible Clues:

• Sudden, involuntary and noisy spasm
• Reason to say 'Gesundheit!'
• See that it's likely to be cold with the Zen
• How one knows it's cold, by the sound of it
• It's a blow that it's so cold
• Not the sort of blow to cause 29 across - it may be cold
• You get it on the blower
• Sudden involuntary expiration, associated with a cold
• Nasal eruption from common cold
• One knows where the sound of the blows comes from