Buying fresh air?

Water used to be free but now we pay for it.  Our tap water is so clean that a doctor recently told me it could be safely used to wash wounds without risk of infection.

Might we be buying clean air in the future?  After all the recent smog was not confined to Paris but slowly crept across central and eastern areas of Britain.  Those with health problems were advised to avoid excess exercise.

Cycling doesn't cause smog so surely cyclists have a right to travel in clean air.