I realise this anecdotal, but as a Londoner living in Zone2, I can actually see and feel the difference in air quality. The skyline is far clearer on average,

I realise this anecdotal, but as a Londoner living in Zone2, I can actually see and feel the difference in air quality. The skyline is far clearer on average, and I definitely notice myself breathing easier, and I do not have asthma or any other respiratory or even allergy issues.