|September 28, 2015|
Deadly diesel pollution has been hiding in plain sight
|The impact of long-chain hydrocarbons found in emissions from diesel engines, largely unobserved and unreported, has been detailed in a new study from the University of York study.|
According to the research, "longer chain hydrocarbons released from diesel vehicles are not considered explicitly as part of air quality strategies and there are few direct measurements of their gaseous abundance in the atmosphere". However, the research team devised a methodology for measuring levels of the hydrocarbons, which are precursors to the formation of ozone and particulate matter, both of which are regarded as pollutants of particular concern.
The impact of long-chain hydrocarbons has been largely ignored by both car manufacturers and official air quality measurements, but that could be about to change.
The lead author of the study, Dr Jacqueline Hamilton, told the BBC that "there's actually a lot of this unburned material from diesel that we haven't seen before. That might be having a bigger impact on ozone and particle formation than petrol cars are, and historically no one has looked at these emissions at all."
Particulate matter is known to have a potentially devastating impact on the health of those exposed to it. The study observed that right now in the UK, exposure to particulate matter is estimated to reduce life expectancy on average by around seven to eight months, with a public cost estimated at up to £20 billion per year.
The study, carried out in London, found that almost 50 percent of ozone production in winter was due to long-chain hydrocarbons from diesel, which also contributed to 25 percent of summer ozone formation.
"I think it is having a large impact on air quality in our cities," said Dr Hamilton. "The number of deaths associated with particle pollution are much higher than those from nitrogen dioxide, this is a route to increase particle pollution so it could have a major impact on human health."
Media attention has turned to diesel pollution following the revelation that Volkswagen falsely reporting its cars' diesel emissions in the USA. It's long been known that diesel contributes heavily to air pollution, but following the signing of the Kyoto protocol climate change agreement in 1997, Europe supported and subsidised the sale of diesel cars due to their lower CO2 emissions.
Professor Paul Monks of the University of Leicester, who chairs the UK government's air quality expert group, told the BBC that the new research "raises yet another question about diesel vehicles. They are implicated heavily in NO2, they are implicated in toxic particulate matter, and this points to another deleterious environmental impact from diesels," he said.
Nitrogen dioxide (NO2) pollution from diesel contributes to the formation of photochemical smog such as that seen across Europe earlier this year.