Tobacco smoke more toxic than car fumes - report

Fresh impetus has been added to the Minister for Health's smoking ban with the publication of research indicating environmental tobacco smoke (ETS) is 40 times more toxic than vehicle exhaust fumes.

Two University College Dublin academics decided to carry out the research following a pre-smoking ban complaint on RTÉ by an angry publican that vehicle pollution was far more dangerous than tobacco smoke.

Well, is it? According to Dr David Timoney, senior lecturer and Director of the Energy Conversion Research Centre at UCD and Mr Shane O'Sullivan, an air pollution researcher at UCD, the opposite is the case.

Dr Timoney says initially it seemed improbable the 188 tonnes of pollution produced by 7 billion cigarettes smoked in the State annually could pose a greater health risk than the 3,449 million tonnes of pollution from the 1.85 million vehicles on Irish roads.

However, the key is the concentrations of pollutants and whether they are indoors or outside an enclosed environment.

To measure the percentage of ETS in the air of a pub the researchers drew up an equation estimating that 30 per cent of 80 patrons in an average pub smoke two cigarettes per hour.

To determine how often the air in the pub changes, the researchers then referred to a study of 14 Galway bars in 2001 which suggested the ventilation rate in these pubs was 2.5 times per hour. Dr Timoney said higher ventilation rates existed and, indeed were recommended, but that for this study they were interested in an average.

According to Dr Timoney, this rate of ventilation gives an ETS pollution concentration of 1,482 microgrammes of ETS per metre cubed.

The researchers then took data from an air pollution measuring site at College Green on Dublin, run by the Corporation. This site consistently has the highest pollution levels of carbon monoxide, nitrogen oxide and hydrocarbons in the State.

"What we found is that although there is a specific level of background pollution for someone on the street, the peaks, like when a bus passes you, only last for a few breaths because the air changes very quickly," said Dr Timoney.

This monitoring station gave a pollution concentration of 37 microgrammes of ETS per metre cubed, with a maximum of 127 microgrammes of ETS per metre cubed.

The Vintners' Federation of Ireland said the estimation of 2.5 air changes per hour is out of date.

· A more detailed explanation of Dr Timoney and Mr O'Sullivan's research is available in this month's Engineers Journal.