Roberts is known as Dr Dust for his work and his obsession with vacuuming. Children are more at risk than adults, because they have a higher metabolic rate and their organs are still developing. Kilogram for kilogram, for example, Emma and Johnny inhale 23 times as much air as their parents. And even relatively low levels of the poisons in dust could irritate their lungs, damage their developing nervous systems, retard their growth and hearing, or lead to cancer. That's the equivalent of smoking three cigarettes a day.
Carpets are one of the biggest sources of toxic substances, the latest research shows.
Normal vacuuming leaves in more dust than it picks up so that, over time, dust accumulates in carpets. That's bad news for people living in cold climates, where most houses boast fitted carpets. Britain tops the charts with over 90 per cent of homes carpeted, compared with about 65 per cent for Germany and about 60 per cent for the US, according to 1997 figures compiled by the Healthy Flooring Network, a coalition of health and environmental groups based in London. By now, most of the children are playing under the table. Johnny, who has been licking his hand, is rubbing it on the carpet.