Stand next to a busy road and a typical half litre breath can contain around a million tiny pollution particles, many with diameters smaller than the wavelength of light. Fortunately, most of these are breathed straight back out again but tens of thousands will deposit in our lungs and airways. Humans have evolved to deal with big dust particles but the sheer volume of particles from modern pollution sources might be putting strain on our respiratory and cardiac systems. A small number of studies (including one in London) have linked the number of particles in the air to heart rhythm problems and increases in deaths, ambulance calls and A&E admissions for heart attacks.

There has been little or no improvement in urban air pollution in the last ten years. However the number of particles has changed dramatically. Ultra low sulphur diesel, first sold in the UK in late 2007, decreased the particle number close to roads by around 60% almost overnight. Even away from busy roads, the number of particles outside our homes and schools also showed a large drop. The number of particles coming from the exhausts of new cars should decrease further with new EU regulations. However, if we want to manage particle numbers, we will also have to tackle other large sources including airports, where particle number emissions per kg of fuel burnt are ten times those from traffic. Large numbers of particles can also be found indoors from wood burners, cooking and cigarette smoke.

via Pollutionwatch: Take a deep breath – and worry | Environment | The Guardian.