Carpets harbour 'toxic dust'

Children are more susceptible to home pollutants

People should run the vacuum cleaner over their home carpets up to 25 times a week to beat the danger posed by toxic dust, claims an environmental engineer in the United States.

Interviewed in New Scientist magazine, John Roberts said that a typical sample of household carpet dust sent to an environmental lab contained high levels of heavy metals, polycyclic aromatic hydrocarbons (PAHs), pesticides and polychlorinated biphenols (PCBs).

The answer, he said, was to adopt a compulsive vacuuming policy, cleaning the carpet near the main entrance with 25 passes a week using a cleaner with a power vacuum head.

The carpet is the largest reservoir of dust in a house

John Roberts
Environmental engineer

Buying a high-quality doormat, or, better still, leaving shoes at the door was a good idea, too, he said.

Mr Roberts said he had put his ideas into action in one home and reduced carpet lead levels from over 18 times the official safety threshold to 13 times below it in 14 months.

Reservoir of dust

A few weeks of such a strict cleaning regime would reduce deep dust levels and allow vacuuming to be scaled back to as little as four passes once a week, he said.

"The carpet is the largest reservoir of dust in a house, so that a house with bare floors and a few area rugs will have about one-tenth of the dust found in a house with wall-to-wall carpet," he told New Scientist.

The New Scientist article referred to research tracing domestic pollution to sources such as tobacco smoke, cooking fumes, household insecticides and garden pesticides.

Lingering DDT

It quoted Robert Lewis of the United States' Environmental Protection Agency as saying that long-banned pesticides such as DDT are often present in carpet dust because carpets are not subject to outside forces like sun and rain, which would normally break down pollutants.

An EPA study also found that domestic pesticide levels were increased up to 400-fold by contamination trodden in on the feet of people and pets, it said.

The information ties in with research published in 2000 in the journal Nature, which suggested that carpets trapped pollutants from car exhaust.

Carpets are much more common in northern Europe than in southern Europe, and an Italian team found indoor pollution to be worse in Antwerp, Rouen, and Copenhagen than it was in Padua, Murcia, and Athens.

A report published at the University of Southampton, UK, in the same year also blamed carpets for harbouring asthma-promoting allergens from dust mites.