There is a pseudoclaim that the oxygen level in the air drops at night and in the early morning (before dawn), and that the change is of sufficient magnitude to influence health.
closed as off-topic by Oddthinking♦ May 16 '15 at 3:01
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "Skeptics Stack Exchange is for challenging unreferenced notable claims, pseudoscience and biased results. This question might not challenge a claim, or the claim identified might not be notable." – Oddthinking