Where’s worst for pollution?

THE AIRPORT TANNOY announcement confirming a delay to our flight mentioned ‘weather conditions’ as the cause. We were in the western Chinese city of Ürümqi, and what looked like fog blanketed the runway. But it wasn’t fog. It was something much denser and more toxic, a cloud of pollution, and it paralysed the airport for hours. Step outside and the smell was unmistakable: acrid
but also slightly sweet.

China has attracted the most headlines for the appalling state of its air. In some cities, readings for key pollutants go far beyond World Health Organization limits and reach the highest point on the scale. But air quality is a problem that afflicts cities around the world: Delhi now has the unenviable
title of being the world’s worst. And while Britain’s air is far cleaner than in the days of the ‘pea soup’ smogs that gripped London until the 1950s, there is still a problem. In one form of pollution, nitrogen dioxide, a dozen British cities have breached EU standards for years.

Since I started reporting on pollution, I’ve become far more sensitive to it. Film beside a major road for more than a few minutes and you can’t miss the odour. Wash your hands afterwards and the dirt in the basin can be shocking. Most shocking of all was visiting a pollution monitoring station in central London and holding a pair of filters: one was new and white, the other had been sampling the air for 24 hours and was dark grey. That grey is in the air we breathe.

Researchers are getting better at working out where this stuff is coming from. Most UK pollution is homegrown, but a lot also blows in from the Continent – a mix of gases and microparticles produced by everything from Parisian traffic to German farmers spraying their fields. The evidence about health effects is mounting up, too. Pollutants can enter the lungs and the bloodstream, and are linked to respiratory and cardiovascular conditions In Britain, pollution causes an estimated 29,000 extra deaths every year, and a forthcoming study may raise that estimate. One piece of advice from pollution scientists: don’t stand beside busy roads any longer than you have to.