Public Health: pollution causes smaller babies

School of Public Health at the University of Medicine and Dentistry of New Jersey has built upon previous research that shows that high levels of pollution cause under-development and malformation in the foetus, as well as premature birth.

Research in the UK has previously shown that traffic fumes are particularly dangerous with those living next to busy roads having the highest incidence of underweight and malformed babies. The UK has a particularly bad record in this regard - more than seven percent of babies are born as clinically underweight - less than 2.5kg.

The New Jersey research says that the reasons why pollution affects the unborn child is not clear: but they identified a correlation with tiny particles - called "particulate matter" that is present in traffic fumes. The most dangerous of these is nitrogen dioxide, say the researchers. The particulate matter is so fine that it can pass through the lungs into the bloodstream, and then to the foetus.

Nitrogen dioxide is produced by both petrol and diesel engined vehicles - but it is that from diesels that is most worrying - it particulates more easily and into small particles - than that from petrol, said researchers from Nagasaki University in Japan - in 1996.

Although in recent years there has been the development of particulate sensors and filters, it remains a significant problem, especially in older commercial vehicles and those that are poorly maintained.

But the problem is not just restricted to motor vehicles: Massoud Mahmoudi, a Californian allegery specialist, published a paper in a book called "Allergy and Asthma - Practical Diagnosis and Management" in 2007 highlighting that Nitrogen Dioxide is produced by the burning of any fossil fuel - and that includes coal-fired petrol stations. He also drew attention to its risks as an allergen.