Are Non-Exhaust Emissions a Health Hazard?

Air quality underground is worse than the air quality overground in London. Overground you're exposed to particulate matter that's being pumped out of cars. Underground system because everything's electrified so instead more dominated by non-exhaust emissions caused by abrasional processes between wheels and tracks. The particles we were observing using our magnetic methods are a very oxidized form of iron. It puts a whole new spin on where a face mask on London transport doesn't it? Richard Harrison from the University of Cambridge who published that work this week in scientific reports.