'Indoor air pollution three times higher than in streets'

Researchers from the Sheffield University in the UK found that indoor air pollution in airtight kitchens can be three times more noxious than traffic-choked streets.

And it becomes more worse by draft-free energy efficient homes, air fresheners and strong cleaning products, they said.

For the study, published in the Journal of Indoor and Buil Environment, the researchers compared three homes -- a rural house split into two flats and used electric cookers and two other city centre apartments using gas appliances.

The scientists took air quality samples from outside and inside the homes over a four-week period, and found that only very low traces of highly-toxic carbon monoxide in the kitchen of the rural house, but levels were much higher in the flats where the gas ovens were turned on.

The gas cookers were a significant source of nitrogen dioxide, with concentrations in the city centre flat's kitchen three times higher than those recorded outside the property and well above the limits recommended, they said.

The research focused on pollutants which pose the biggest risks to the elderly and people with cardiovascular problems, including volatile organic compounds and solid particles small enough to penetrate into the lungs.

Professor Vida Sharifi, who led the research, said: "We spend 90 per cent of our time indoors and work hard to make our homes warm, secure and comfortable, but we rarely think about the pollution we might be breathing in.

"Energy is just one source of indoor pollution, but it's a significant one. And as we make our homes more airtight to reduce heating costs, we are likely to be exposed to higher levels of indoor pollution, with potential impacts on health."

"Concerns about air quality tend to focus on what we breathe outdoors, but as we spend most of our time indoors, we need to understand more about air pollution in our homes.

"Although ours was just a small study, it highlights the need for more research to determine the impact of changing housing and lifestyles on our indoor air quality," she added.