RE: So, does ozone have an odor or not?

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Original poster: "Ian McLean" <ianmm-at-optusnet-dot-com.au> 

Hi all,

I majored in chemistry.  I may be able to shed some light here.

 > It seems to me that it is the ozone that we're smelling, not the NO.
 > BTW, does NO have the same detrimental effects to health at such low
 > concentrations as does ozone? Like I said, doctors and dentists often
 > deliberately make us breath nitorus oxide (some call it laughing gas)
 > to put us out so they can operate on us w/out us feeling the pain.
 > This form of NO must not be very toxic at all or it certainly couldn't
 > be used so freely as an anesthetic. Maybe some of the
 > resident chemistry
 > majors could comment further on this subject?

The ionisation effects of HV produce O3 from recombined ionized oxygen
atoms.  Nitrogen ionizes at a much higher voltage, but will combine
molecularly (i.e. oxidize, or burn), at about the same power levels in a
plasma arc with available oxygen to create various oxides of nitrogen,
predominantly NO and NO2.

So, from any chemistry text on gases, you will find that:

O3, ozone, has a sweet garlic-like odor.  Blue in color.  Toxic.
Second strongest oxidizing agent in the world (next to oxygen of course !)
Relatively large quantities produced by high voltage arcs (much larger than
recommended safe levels anyway).

Note, O2 is mostly colorless, although I have read somewhere that it does
have a very slight blue tinge, as does pure water !  Some one did an
experiment on this I believe.  By putting pure water into a very long tube
and putting lenses on both ends and pointing one end at a light source, the
slight blue tinge can in fact be seen.

NO, nitrous oxide is colorless and odorless (dental gas, cream whipping
gas).  Gives you a nice high ;)  Originally thought to be non-toxic, I
believe some now say it may have some carcinogenic effects.  Produced in
smallish quantities.

NO2, nitrogen dioxide, is a brown-red coloured gas, smells similar to
chlorine or bromium.  Highly toxic and caustic.  Produced in reasonable
quantities, more at higher power levels.

NO3, nitrogen trioxide, is a red coloured gas, smells similar to NO2 only
stronger, is very, very highly toxic and caustic.  Condensed into a liquid,
this forms pure nitric acid, and is one of the basic ingredients in the
manufacture of RDX based high explosives such as C4.  Trace quantities maybe
produced at high power levels.

Hope all this helps.

Rgs
Ian