Tube air 'better than outdoors'

Underground dust is too low to pose a health risk, say researchers

The Underground has much lower levels of pollution than the air around London's busy roads, say researchers.

A study found the Tube has far lower levels of more dangerous ultra-fine particles, thought to be damaging to health, than are found on busy roads.

The Tube has larger dust particles that are made of iron, rather than carbon.

The team, writing in Occupational and Environmental Medicine, found any harmful minerals were well below levels allowed in the workplace.

The number and size of dust particles was measured at various Tube stations and in drivers' cabs and then tested for toxicity levels.

'Serious disease'

Compared with outdoor air, the researchers found that dust levels were high in mass on the Underground, but low in terms of particles.

The researchers said that weight-for-weight the risks from Underground dust were much more comparable to iron oxide welding fumes than to particles in the air outdoors.

But they said that the exposure was much lower than would be needed to cause lung disease.

"We concluded that risks of serious disease of the lungs or heart from exposure underground would be very low, and probably difficult to detect," the researchers, from the Institute of Occupational Medicine in Edinburgh, said.

"Above ground you will breathe traffic fumes, below ground less of that but some iron oxide."

They said Tube commuters at risk from dust inhalation should not be seriously concerned, but that efforts to reduce dust concentrations should continue.