Cycling to work may seem the healthy
option, but a study has shown that people riding in cities inhale tens of
millions of toxic nanoparticles with every breath, at least five times more than
drivers or pedestrians.
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. The particles, when
inhaled, have been linked to heart disease and respiratory
problems.
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.
"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," said Luc Int Panis of Hasselt University in Belgium, who led the
study.
For the research, Int Panis and his colleagues asked cyclists
to pedal while wearing a mask fitted with instruments that could count the
particulates, as the particles are known.
The researchers found that
in Brussels the cyclists inhaled 5.58 million nanoparticles for every metre
cycled, dropping to 1.1 million when they tried the experiment in Mol, a
smaller town in Belgium. They also found that the cyclists inhaled 4-5 times
more particles than a car passenger driven along the same route.
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