Nitric oxide in air constitutes what is called ‘ambient NO’. Most of the inhaled ambient NO enters the pulmonary blood by diffusion and binds to hemoglobin.The residual NO becomes part of the exhaled breath that only appears in the initial wash-out phase of a typical 11-second exhaled breath. Ambient NO is a function of the location, time of day etc. and can vary between 0 ppb and upwards of 200 ppb.

1. Ambient Nitric Oxide: The Real Insight
Ambient Nitric Oxide: The Real Insight
The Insight eNO System does NOT require inhalation of NO free
air
The ATS/ERS recommendations (2005) for standardized measurement of exhaled nitric
oxide states that it is not necessary but only preferred to use NO (nitric oxide) free air for
inhalation. The Insight™ eNO System does not require NO free air to be inhaled prior to
the measurement because ambient NO (nitric oxide in air) does not interfere with the
results.
The findings of the study are detailed below.