Spontaneous chemiluminescence of human breath. Spectrum, lifetime, temporal distribution, and correlation with peroxide.

Human breath spontaneously emits photons at a rate of approximately 7,000/liter-s. The emission has a peak in the red part of the spectrum and an ultraviolet contribution. The emission count rate correlates with peroxide concentration in a saturating manner under normal breathing conditions. When trapped in a balloon, the breath luminescence count rate has a half-decay time of approximately 20 min and exhibits more than one mode of decay. The photomultiplier pulses generated by breath luminescence arrive in bursts. The chemiluminescence process appears by these criteria to include chain reactions, long-lived emitters, or both.