Pollution higher indoors

Pollution inside homes and offices can be up to double the level recorded outdoors, new research has revealed.

Tests carried out for the European Commission show that levels of the chemical benzene are twice as high indoors as outside. The toxin, found in both fitted carpets and cigarette smoke, is a major cause of leukaemia.

It is thought the chemical could be responsible for up to six million cases of the disease across Europe. Despite fears that industrial pollution and fumes produced by heavy traffic pose the biggest environmental threat to health, the study by the Commission found that plastics, furniture, computers, carpets and cigarette smoke are causing an increase in the number of people suffering from allergies. The research suggests a combination of tobacco smoke, asbestos, radon and benzene released in buildings could be causing an increase in cancer rates.

Researchers also measured levels of other toxic chemicals, including xylene - found in paint and varnish - ethylbenzene and toluene in school buildings, and discovered children were exposed to them in classrooms.

Long-term exposure to xylene and toluene has been linked to brain damage. Philippe Busquin, the European Research Commissioner, said more work was desperately needed to discover the impact on health.

"Traffic and smog are, of course, major causes of pollution and we are studying and analysing their impact on human health," he said.

"But unfortunately smoking and chemical substances sometimes follow us even behind closed doors - at home, at the office, in restaurants and bars.

"We can be at risk while sitting on our sofa at home as well as cycling downtown in the rush hour."

The research found that tobacco was particularly hard to remove from the air inside buildings - even with the most sophisticated ventilation systems.

Using a revolutionary new measuring device, called the Indoortron, scientists discovered that tobacco components remained concentrated in the air even after air conditioning had been switched on. Mr Busquin said: "We are therefore upgrading our indoor pollution monitoring and response capabilities, and we encourage policymakers and public authorities across Europe to address these issues, and devise a consistent and effective strategy to solve the problem".

The Commission is drawing up a list of substances which need to be regulated in indoor environments, guidelines on safe levels of exposure, and proposals on how the public can be protected from coming into contact with them.