Monday, June 19, 2017

Did government encouragement of diesel use lead to more pollution?

See The End of Diesel: The highly efficient fuel was supposed to be the future. Is it now doomed? by Nicholas Clairmont of The Atlantic. Excerpts:
"Once upon a time, diesel fuel was going to be the future. It was seen as more efficient, on a mileage-per-gallon basis, than other fossil fuels, and for that reason was also thought to be less polluting.

About two decades ago, acting on those beliefs, policy makers in Europe—where high energy prices already made mileage a more-pressing issue than in the U.S.—made a number of rules that incentivized the growth of diesel over gasoline for use in passenger cars, moving past its traditional role in trucking and construction.  

These policies were remarkably successful at meeting their goals, and diesel-powered cars soon accounted for half of the cars sold on the continent. Car companies poured resources into developing diesel-related technology. But the result of this success has been not greener, friendlier, cheaper motoring, but the creation of toxic clouds over major European cities. At the end of 2016, Paris was choked by its worst episode of smog in more than a decade, lasting longer than two weeks, according to the city’s pollution-watching agency Airparif, and prompting the city to enact emergency measures that included restricting car use. It was not the first time. During a March 2015 pollution event, Paris was briefly the most polluted city in the world, surpassing famously smoggy Beijing. London shared in the ignominy when it too beat out Beijing for the first time in January of this year.  

Diesels have played the main role in this. Since the 1960s, advances in technology that treats and filters gasoline engines’ exhaust, like the widespread use of catalytic converters, have cut down on the amount of dirty, unhealthy, and smog-producing emissions these engines spew out into the surrounding environment. But while diesels get better mileage and so contribute less to global climate change, the local effects of diesel pollution are much worse than those of gasoline. Diesel is a less refined fuel, and so it contains more of the particulate matter that can have deadly health effects when spewed into the surrounding environment. And burning diesel produces, among other noxious gases, nitrogen dioxide, the main cause of smog.

In many cases the same regulatory bodies that were trying to get citizens into diesels only a few years ago are now working to get the engines off the road entirely, instituting additional, diesel-specific congestion-charging and other disincentives in cities, in recognition of the fact that their green-friendliness was mistaken. During particularly bad bouts of smog, several European cities have temporarily banned driving outright, or instituted restriction schemes where, for example, cars with odd and even number plates are allowed in on alternate days. The mayors of Athens, Mexico City, and Madrid have committed to ridding their cities of diesel cars altogether by 2025, and Paris Mayor Anne Hidalgo said “there will be no diesel vehicles in Paris in 2020.” Other cities around the continent and world are implementing smaller-scale efforts to discourage diesel too."

"Policy makers, particularly in Europe, moved to incentivize diesel in the ‘90s and ‘00s with tax breaks at the pump, and they tightened regulations that focused on mileage per gallon (or the equivalent European measurement unit, liters per 100 kilometers), which inherently favor Rudolph Diesel’s thermodynamically efficient engines over gasoline-powered ones that use more gallons but spew fewer toxins. In some countries, including France and Spain, taxes were lower on diesel cars than gas ones. The market share of diesel cars in Western Europe went from less than 14 percent in 1990 to half today, after touching a high of 56 percent in 2011. As Bloomberg’s Leonid Bershidsky points out, Japan had a similar rate of diesels at the turn of the millennium, but absent similar policies, those in Japan more or less disappeared over the period that diesel sales in Europe tripled, as Japanese manufacturers pushed into hybrids."

"In Europe, meanwhile, the push for diesel has turned out to be a disaster. “They're these relatively powerful and efficient engines that are kind of deadly in terms of their emissions,” said Timothy Lipman, the co-director of the Transportation Sustainability Research Center at the University of California, Berkeley. The “deadly” effects Lipman refers to are extremely serious. Both the nitrogen oxides that come from diesel engines’ high-compression combustion and the fine, sooty particulate matter that can get into human tissue carry serious health effects that cost lives. In addition to lower respiratory diseases like chronically obstructive pulmonary disease and asthma, which they can cause especially in children and worsen among people who are already asthmatic, particulate matter in the engines’ fumes is associated with heart attacks, lung cancer, and strokes, among other things.

“I'm sure the levels of particulate matter and nitrogen oxide as well would be much, much lower in European cities if they didn't have the incentives they had for diesel cars,” said Helotonio Carvalho, a molecular biologist at Brazil’s Federal University of Pernambuco, Recife. He added, “We are going in a direction where diesel cars probably won't have a place.” Carvalho has written in the medical journal The Lancet that 400,000 people died prematurely from all the various sources of air pollution in Europe in 2011. I asked him how many deaths can be attributed specifically to Europe’s elevated rate of diesels, relative to, for example, North America or to his native Brazil, where diesel passenger cars haven’t been allowed as a matter of policy. He told me that the number is in the “hundreds of thousands.”"

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