Economical: Wood-fired sources of heating have become increasingly popular to cut heating costs, with 200,000 stoves installed a year

They are in hot demand among Britons hoping to save money on energy bills. But trendy wood-burning stoves are fuelling air pollution, scientists warn.

Research shows levels of a particularly nasty form of pollution surge during winter when stoves and open fires are lit.

Wood-fired sources of heating have become increasingly popular to cut heating costs, with 200,000 stoves installed a year. Estate agents say they can add up to 5 per cent to a house’s value.

They are also seen as environmentally friendly because carbon dioxide released by burning wood is taken up by young trees – making the fuel carbon neutral.

As a result, homeowners can get government subsidies if they install wood-fired boilers.

But wood may not be as green as it seems. Scientists from King’s College London say burning wood generates particulates – minuscule particles that can raise the risk of heart disease, trigger asthma and shorten lives.

Their research shows levels surge during winter evenings – when wood-burning accounts for 13 per cent of particulates in the air in some British cities.

In some hot spots, the pollution is comparable to that from traffic fumes.

Researcher Dr Gary Fuller told the Sunday Times: ‘Although the apparent carbon neutrality of wood may make it appear environmentally friendly, there is growing evidence of adverse health effects from wood smoke.

‘Domestic wood burning takes place where people live and at times when they are at home.

‘Coupled with still night-time conditions even modest wood-burning in urban areas may lead to particulate exposures comparable to those from traffic sources.

‘We need to manage urban emissions to ensure increased wood-burning does not offset schemes to reduce traffic pollution.’

Lethal: Scientists from King’s College London say burning wood generates particulates – minuscule particles that can raise the risk of heart disease, trigger asthma and shorten lives

The Stove Industry Alliance, which represents manufacturers, said that modern stoves are greener than their predecessors.

Hugh Wells, the association’s deputy chairman, said: ‘Wood-fired stoves are a genuinely green and carbon neutral way of heating your home, which can save you money and make you less dependent on the big energy companies.

‘Modern stoves are very efficient and clean, with about 14 milligrams of particulate per cubic metre of air.

‘The compares to 100mg five years ago.’