This goes beyond VW - we need to wean ourselves off killer diesel
Governments must now use the tax system to reverse the drift from petrol to noxious diesel, writes Colm McCarthy
The resignation on Wednesday of Volkswagen chief executive Martin Winterkorn followed revelations that the company had been fiddling emission tests on diesel cars in the United States, provoking the threat of large fines by US regulators and a collapse in the share price. Volkswagen is, with Japan's Toyota and General Motors of the US, one of the world's big three automakers, with annual sales that exceed Ireland's GDP.
Diesel engines give better mileage than petrol, hence causing lower emissions of greenhouse gases into the atmosphere per kilometre travelled. But they produce higher emissions of local pollutants, including particulates and nitrogen oxide, and these are known to have adverse effects on human health, especially in built-up areas.
Governments in Europe and elsewhere have been encouraging a switch from petrol to diesel for the last two decades in pursuit of a reduction in greenhouse gas emissions. Conscious of the side-effects in terms of particulates and nitrogen oxide, they have sought to limit these damaging low-level emissions through regulation and testing, while favouring diesel through the tax system.