Saturday, July 15, 2017

Even Diesel Burns Cleaner than Gasoline #Science #Environment

The information in this one isn't so sexy but it's a champion surprise since I never would have guessed diesel fuel can be burned cleanly.

If you ever make the mistake in using the wrong nozzle with diesel, it will be such a screaming hassle to get it pumped back out again you won't likely err that way again - One Who Knows

Modern diesel cars emit less pollution generally than cars that run on gasoline, says a new six-nation study published today in Scientific Reports whose groundwork was laid in part by an American chemist now working at Université de Montréal.

And since diesel is so much cleaner than before, environmental regulators should increasingly shift their focus to dirtier gasoline-powered cars and other sources of air pollution, says the UdeM scientist, Patrick Hayes.

"Diesel has a bad reputation because you can see the pollution, but it's actually the invisible pollution that comes from gasoline in cars that's worse," said Hayes, 36, an assistant professor at UdeM.

"The next step should be to focus on gasoline or removing old diesel vehicles from the road. Modern diesel vehicles have adopted new standards and are now very clean, so attention needs to now turn to regulating on-road and off-road gasoline engines more. That's really the next target."  Diesel is now better than gas, study says

You're probably not too keen on the idea of gasoline as a target, Mustang Sally, but that does appear to be the situation and you see part of the case for it above.

The study, led by researchers in Switzerland and Norway with help from Hayes and colleagues in Italy, France and the U.S., looked at carbonaceous particulate matter (PM) emitted from the tailpipes of cars.

Carbonaceous PM is made up of black carbon, primary organic aerosol (POA) and, especially, secondary organic aerosol (SOA), which is known to contain harmful reactive oxygen species and can damage lung tissue. 

In recent years, newer diesel cars in Europe and North America have been required to be equipped with diesel particle filters (DPFs), which significantly cut down on the pollution they emit.

In the lab (at the Paul Scherrer Institute, near Zurich in Switzerland), "gasoline cars emitted on average 10 times more carbonaceous PM at 22°C and 62 times more at -7°C compared to diesel cars," the researchers noted in their study.

"The increase in emissions at lower temperatures is related to a more pronounced cold-start effect," when a gasoline engine is less efficient because it's not yet warned up and its catalytic converter is not yet on, the study noted.

- PO

There you have the numbers and burning gasoline isn't just worse, it's much worse.

It added: "These results challenge the existing paradigm that diesel cars are associated, in general, with far higher PM emission rates, reflecting the effectiveness" of engine add-ons like DPFs to stem pollution.

That said, it is true that older diesel cars do pollute more than gasoline cars, because they don't have DPFs, and diesel cars in general emit far more nitrogen oxides, which cause smog and acid rain, the study also noted.

- PO

I take the last to mean diesels need to go too but they want to go gunning for gasoline first.

Look at the bright side since America can one day make smog tours a tourist attraction because the U.S. will cling to internal combustion until its bony fingers lose their strength and long after everywhere else has walked away from it.

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