AIR POLLUTION

CLEAR proof that diesel fumes causes breathing problems has finally been found by scientists.

Polluted air contains tiny particles that make nerves in the lungs misfire, triggering coughing and wheezing.

It is clear evidence of the precise way in which diesel fumes spark asthma attacks and leave sufferers in need of medical assistance, if not hospital attention. The particles are also linked to premature births as well as heart and lung disease.

Air pollution, including diesel fumes, has been blamed for up to 40,000 deaths a year.

A research team led by Imperial College London found that the particles were dangerous because they were so small the body did not recognise them as foreign objects.

Professor Maria Belvisi, the study’s lead author, said: ‘We knew that people exposed to traffic were more likely to suffer from asthma attacks, coughing and breathlessness.

‘This is the first direct evidence that diesel is doing it.

‘The symptoms are being caused by activation of the nerves in the airway. It is more of an issue for people with existing breathing problems and asthma, but this is happening to all of us.’

Diesels are so common because drivers were given financial incentives to buy them under the last Labour government.

Their engines were favoured because they emit less carbon dioxide, a greenhouse gas.

Dr Penny Woods, of the British Lung Foundation, said the study confirmed the serious and potentially fatal consequences of diesel fumes.

She added: ‘Diesel emissions have become the major source of pollution in urban areas, where the majority of people live. We are storing up huge unknowns for the future of our nation’s respiratory health.

‘We need the next Government to urgently implement a new clean air act that recognises the modern-day source of traffic emissions and cleans up the air we breathe.’

The Government has published draft plans to offer drivers cash for scrapping their diesels. But campaigners are calling for clean air zones, keeping polluting vehicles out of urban areas altogether. Thirty-Seven cities persistently breach legal limits of air toxins.

Although diesel particles are mainly carbon, the chemicals on their surface – polycyclic aromatic hydrocarbons – are dangerous.

Testing diesel fumes on human lung tissue, animal tissue and guinea pigs, the Imperial College team found these chemicals triggered coughing.

Dr Ian Mudway, of King’s College London, said: ‘This study shines a mechanistic light on how the very small particles emitted from diesel exhaust worsen respiratory symptoms by activating airway nerves and highlights the importance of polycyclic aromatic hydrocarbons.’

The diesel particles are so tiny that the body mistakes them for natural molecules and draws them into the lungs. The study involved the University of British Columbia and is published in the Journal of Allergy and Clinical Immunology. Professor Belvisi added: ‘The main message here is about prevention. A significant number of hospital admissions are for people suffering with exacerbations of respiratory disease.

‘In major cities we are already exceeding the recommended levels for air pollution.’