All choked up: did Britain's dirty air make me dangerously ill?

This year, environment correspondent John Vidal had heart bypass surgery - a wake-up call that prompted him to investigate the state of the air we breathe. With 29,000 UK deaths a year attributed to pollution, is it time we cleaned up our act?

Three months ago, a surgeon at Liverpool Heart and Chest hospital took a saw, ripped through my sternum, levered open my ribcage, cut into the aorta of my still-beating heart and stitched in a vein from my leg. The long, brutal operation was a great success. But it knocked me out and left me unable to walk more than a few paces.

As I recovered, I got to asking how had I got into this mess. I had always, I thought, kept pretty fit: I could happily walk all day in the hills, chop wood, play cricket and dig deep. I ate good food and loved exercise. So what else was there in my lifestyle that could have led to heart disease, Britain's biggest killer?