”This is the first time anyone has counted the particles while also measuring people’s breathing during city commuting. It showed that cyclists can inhale an astonishing number of pollutant particles in one journey.

The research showed that urban concentrations of nanoparticles, which measure just a few millionths of a millimetre, could reach several hundred thousand in a cubic centimetre of air. Because they are exerting themselves, cyclists breathe harder and faster than other road users. The study found that they suck in about 1,000 cubic cm with each breath, meaning they may inhale tens of millions of the particles each time they fill their lungs, and billions during a whole journey. The particles, when inhaled, have been linked to heart disease and respiratory problems. Wearing a mask offers little protection as the particles are so small that they pass straight through any shield.

Toxic cities mock ‘healthy’ cycle riding