The number and size of dust particles was measured at various Tube stations and in drivers' cabs and then tested for toxicity levels.
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."
Well there you go then. Anthony you have no need to wear your dustmask anymore.
The boffins from the Institute of Occupational Medicine in Edinburgh, concluded "risks of serious disease of the lungs or heart from exposure underground would be very low, and probably difficult to detect,"
"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.