Hi
Could you say, is there a difference between clear air and pure air?
Before I always considered (for no particular reason :)) that clear air refers to visibility aspect, its transparency, whereas pure air - to its freshness and suitability for breathe.
But now I’ve lost my great guiding rule… 
No hunting, shooting or fishing for them, but walking and gardening and breathing in the clear air.
?
Until a couple of minutes ago I’d have said that pure air is synonymous with clear air. But now, the more I think about it, the less sure I am! :?
Sorry for confusing you even more!
Sorry… :lol:
2 cents from me
clear air - visible, transparent
clean air - suitable for breathing, not polluted
pure air - clear air
Hi Tamara
Some rambling comments and thoughts from me: 8)
I’ve been asking myself whether saying “pure air” can/should be used at all since the word pure is so frequently used to indicate that something is made up of 100% of one element without any additional matter: pure gold.
But air doesn’t ever consist of only one single element. I think I’d be more willing to say ‘pure oxygen’ than to say ‘pure air’.
If you did say ‘pure air’ I would probably understand that you were trying to say that the air is not polluted.
But, as is often the case, it would probably also depend on the whole context.
Amy
Thank you, SkiIucK
And what about water, do you have a tuppence more for me? 
Hmm. I remember that once in Scotland, when we were visited Lock Lomond, my What (a) clear water! was corrected (with smiling) by ‘Yes, pure water’. (Or… vise versa?… … my memory is like a sieve… )
Thanks, Amy.
Can I ask you a favour?
BNC contains 12 sentences with pure air. Could you list (just list here their identifiers) those, in which use of the expression is ‘not comfortable’ to you?
Hi Tamara,
I’ll wade in here, if I may. It might help to turn these adjectives into abstract nouns: purity and clarity. Then you could tie these up with ‘language’. You know how some people object to ‘foreign’ intrusions into their own language (mentioning no names) well they would talk about the purity of their language in the sense of unalloyed. Then there’s clarity of language, a different kettle of fish, where you’re talking about the clear way in which something is expressed.
Hope I’ve not muddied the waters with these comments!
A
Hi Alan,
Thank you for drawing the analogy (I adore the ‘language=water’ metaphor, you know )
OK.
…Sometimes I feel I need to take the waters (…at a spa)
Hi Tamara
I’ve had a look at the bnc results for “pure air” and nearly all of them use this expression to talk about air that is free of pollutants.
Amy