Cancer risk from vehicle emissions

It is encouraging that the Church Commission, in its proposals on Budget 2009, has recommended that hefty fines should be introduced for the emission of poisonous fumes by public transport vehicles and other heavy vehicles as a result of abuse in the mixing of fuels for economic reasons.

This now introduces a moral dimension to this source of dangerous pollution which is a threat to our health and that of our children.

The fine soot particles emitted by internal combustion engines are dangerous for at least three reasons.

First of all, the rough surface of these particles (or so-called particulates) become impregnated with toxic substances at the extremely high combustion temperatures inside the engine cylinder.

Second, the finest of these soot particles (which are invisible) remain suspended in the air for a very long time - days or even weeks.

Third, the finest particles reach the innermost part of the lung when inhaled, where they accumulate.

This represents the greatest threat to health by causing an increase in the susceptibility to lung cancer and other lung and heart disorders. Living near roads with heavy traffic further increases the likelihood of developing cancer.

The scientific evidence for this is now irrefutable and very worrying. The World Health Organisation (WHO) states as follows: "Long-term exposure to current ambient particulate concentrations may lead to a marked reduction in life expectancy. The reduction in life expectancy is primarily due to increased cardio-pulmonary and lung cancer mortality. Increases are likely in lower respiratory symptom, reduced lung function in children, and chronic obstructive pulmonary disease and reduced lung function in adults."

Reduction of life span from exposure to diesel fumes may vary from around three months where pollution is low to months or years where pollution is high. The decrease in life expectancy of people living in severely polluted surroundings, as in Malta, relative to those living in cleaner environments, is measured in years rather than months. This sort of statistic means that while the more fortunate among us will probably live our allotted span in spite of the severe pollution in Malta, some will be less fortunate and develop cancer, a heart attack, severe asthma or some other pollution-related illness and die at a relatively young age.

A worrying aspect of this pollution is that growing children are very susceptible to the effects of pollution.

In addition to increased severity of asthma and other adverse health effects, exposure to high ambient traffic pollution has been shown to cause retardation of lung development in children. This means that many, if not all, of today's children will grow up into adults with deficient lung function.

The bottom line is this: Even without buses our traffic pollution problem is already serious; buses are adding immensely to this problem. The public is ill-informed about the extent of the pollution to which they are being exposed so that there is generalised complacency. Buses (and many other diesel vehicles) ply their way leaving swathes of black smoke in often crowded streets and very few people are worried by it.

In the meantime the government periodically boasts that VRT tests will be carried out on buses and radiates a feel-good factor and then allows itself to get stalled by ridiculous technical objections and the matter is forgotten, but we all remain at risk.

Our Health Department did a very good job in banning smoking in public places - it is about time that this other more serious threat to health receives attention.