Dave Doe wrote:
In article , ,
Skywise says...

Dave Doe wrote in
:

Water is pollution?

I think you either need to get your chemistry right, or define
"hydrogen" - or perhaps, what you are burning. Hydrocarbons?

Burning hydrogen with pure oxygen produces only water vapor.
For example, LH2 and O2 rocket engines such as the Shuttle's.

Burning hydrogen with 'air' also produces other compounds,
including nitrous oxides (smog, harmful to humans). 'Air' is
not pure oxygen.

Check your chemistry.

Oh I have! Hence the question. I'm sure you've heard of Oxyhydrogen
plants (as in Oxyacetalene plants).

Those are not engines and an oxygen/hydrogen flame exposed to air produces
NOx through the temperatures involved.

It is purely an effect of heating air to a temperature sufficient for
the reaction; the heat source is irrelevant.

--
Jim Pennino