Diesel can trigger allergy attack, scientists say
Despite efforts to clean up diesel-burning engines, their emissions significantly increase the risk of allergic and asthmatic reactions, Norwegian researchers reveal.
‘Dependable’ and ‘cost saving’ are two adjectives commonly associated with diesel engines. In recent years, diesel-burning off-road vehicles have also become a fashionable purchase item for city dwellers around the world. For asthmatics and people with allergies this is a regrettable trend. Particles in diesel exhaust can both worsen and trigger allergic reactions, say the Norwegians behind a government-backed study.
|Diesel more than petrol exhaust can be bad news for allergy sufferers|
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Martinus Løvik of the Norwegian Institute of Public Health’s environmental immunology division led a project to study the effects of diesel engines on people prone to these major ailments. He said the increasing numbers of diesel vehicles on the roads – and their continued use in shipping and rail (especially in Norway) – pose a serious health risk.
His team investigated the prevalence and recurrence of allergies in mice exposed to different airborne particles. The research was financed by the Research Council of Norway, which is a centre of expertise in epidemiology, infectious disease control, environmental medicine, forensic toxicology and research on drug abuse.
100 times more
Diesel exhaust contains about 100 times more carbon particles than petrol. The core of the particle is, in turn, surrounded by many different chemicals. This chemical cocktail not only seems to exacerbate the symptoms of those already prone to allergies but also appears to trigger latent allergic reactions, causing human blood cells to create more antibodies. In mice, the particle core itself appears to play a role, inducing increased allergic immune response.
These results are supported by US studies which found that people who were previously not allergic can develop reactions to diesel if they are ‘nasally’ exposed to the exhaust particles together with mugwort pollen. Diesel particles are minute – less than one-thousandth of a millimetre across – and remain airborne for a long time. This fineness also means that up to 30% of the mass we inhale can be deposited into the lungs.
Even flying dust from speeding tyres – in Norway’s case, spiked winter treads add to this – is less of a potential irritant to the lungs than diesel particles, Løvik explain. “We have to consider pollution from diesel exhaust to be a greater risk than pavement dust, which we have focused… on in Norway over the past years,” he said, adding that recent studies also suggest fine particles can also affect acute heart disease.
The team is also involved in a Europe-wide assessment of ‘Respiratory allergy and inflammation due to ambient particles’ (RAIAP), a project which aims to summarise the scientific knowledge on the role of ambient particles on respiratory allergies and the implications of this for regulators, the general public and industry.
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Norwegian Institute for Public HealthRAIAPNew network to help Europeans breathe easy(Headlines, 3 February 2004)