Two years ago, the health implications of fumes pumped out by diesel cars exploded into the public consciousness with the revelation that Volkswagen was cheating emissions tests. Now it seems that duping regulators with defeat devices software designed to lower exhaust readings during tests is just the tip of the iceberg. Recently we learnt that diesel vehicles including cars, lorries, trucks and buses in much of the world emitted 50 per cent more nitrous oxide (NOx) than they should have in 2015. That equates to 4.6 million more tons of the gas than official certification suggests. Those figures come from research published in Nature that compared real-world emissions to those under test conditions in parts of the world that account for 80 per cent of diesel vehicle sales. For those in the know, this will be no surprise. Almost all diesel vehicles exceed certified emissions on the road, even though they have passed regulatory tests. In no small part, thats because the tests are outmoded and inadequate. Health burden The astounding thing about this regulatory gaffe is the public health burden. At least 38,000 premature deaths resulted from that extra NOx in 2015 alone, says the study. This toll stems from the gas reacting with other chemicals in the atmosphere to produce nasty by-products harmful to health. For example, it boosts ground-level ozone which worsens respiratory conditions such as asthma and bronchitis and ultra-fine particles, which can trigger heart disease and stroke. By modelling the likely future growth of all vehicle NOx emissions, the scientists project that unchecked the annual public health burden will balloon to 183,600 early deaths by 2040. Significant as that figure is, it may well actually underplay the seriousness of the situation. Other recent research shows that oxides of nitrogen may also have direct effects on human health greater than the indirect ones. The death toll from the excess emissions is, perhaps surprisingly, greatest in the European Union, as a result of an upsurge in diesel car use. Thats followed closely by China and India, where trucks and buses are the main culprits. Yet these deaths are avoidable with proper oversight. Car manufacturers can meet the regulations; they just dont always do it. Not held to account The failure of governments to hold to account one of the worlds most polluting industries is perhaps the real scandal. Strong governmental oversight is now needed. The US and the EU, which together certify most new diesel vehicles, must up their game to ensure reliable results from regulatory testing. The good news is that both will introduce fresh policies to that end this year. In Europe, this means a real-driving emissions test to better gauge actual pollution. Done properly, this will help to reinstate public trust in governmental oversight of the auto industry something that has surely been lost. And countries that have yet to adopt strict diesel NOx standards such as Australia, Brazil, China, Mexico and Russia must do so without delay. Global enforcement of even tougher standards would be better still, and it is predicted that this could avoid 174,000 unnecessary deaths in 2040 alone. The problem remains, however, that vehicles will still be able to pollute the air to certified limits, without full knowledge of the consequences for public health. Solving that will be a much greater challenge, but one that we must ultimately aspire to.
New Scientist, 18 May 2017 ;http://www.newscientist.com/ ;