Paris, Madrid, Athens, Mexico City Will Ban Diesel Vehicles By 2025 (bbc.com)

The mayors of four major global cities -- Paris, Mexico City, Madrid and Athens -- announced plans to stop the use of all diesel-powered cars and trucks by 2025. The leaders made their commitments in Mexico at a biennial meeting of city leaders. BBC reports: At the C40 meeting of urban leaders in Mexico, the four mayors declared that they would ban all diesel vehicles by 2025 and "commit to doing everything in their power to incentivize the use of electric, hydrogen and hybrid vehicles." "It is no secret that in Mexico City, we grapple with the twin problems of air pollution and traffic," said the city's mayor, Miguel Angel Mancera. "By expanding alternative transportation options like our Bus Rapid Transport and subway systems, while also investing in cycling infrastructure, we are working to ease congestion in our roadways and our lungs." Paris has already taken a series of steps to cut the impact of diesel cars and trucks. Vehicles registered before 1997 have already been banned from entering the city, with restrictions increasing each year until 2020. The use of diesel in transport has come under increasing scrutiny in recent years, as concerns about its impact on air quality have grown. The World Health Organization (WHO) says that around three million deaths every year are linked to exposure to outdoor air pollution. Diesel engines contribute to the problem in two key ways -- through the production of particulate matter (PM) and nitrogen oxides (NOx). Very fine soot PM can penetrate the lungs and can contribute to cardiovascular illness and death. Nitrogen oxides can help form ground level ozone and this can exacerbate breathing difficulties, even for people without a history of respiratory problems. The diesel ban is hugely significant. Carmakers will look at this decision and know it's just a matter of time before other city mayors follow suit.

Comments

Re:I thought diesel ran cleaner

[Solandri]

I've wondered about this too. I've noticed pollutants in emissions are measured in PPM - parts per million air molecules in the exhaust. Not in parts per distance traveled. So transportation efficiency (emissions per distance traveled) gets you nothing (volume of air ingested decreases with higher efficiency), and combustion efficiency (more energy produced per cylinder detonation) actually increases PPM even though in practical terms it would be offset by needing to fire the cylinder fewer times to get the same amount of work done. Meanwhile being able to run a lean mixture makes passing these emissions tests a breeze. Heck, you could rig up a bypass to feed intake air straight into the exhaust stream (probably illegal) and drop your PPM to near-zero.

e.g. My 3.0L V6 diesel truck cruises at 65 MPHat 1550 RPM. My 3.2L V6 gas car cruises at 65 MPH at 1800 RPM. 7% higher engine displacement, 16% higher RPM, so 23.9% more airflow volume at the same speed. So even if the diesel put out 23% more PPM than the gas engine, it would actually be emitting less pollutants per mile traveled. The difference is even more pronounced at higher speeds or loads. The diesel can hit 80 MPH at 1900 RPM, while the gas engine will be up around 2400 RPM. 35% higher airflow.

Re:So much for biodiesel use...

[Anne Thwacks]

They pollute more, even as they consume less.

This is not really true. The type of polution from engines is heavily influenced by politics. And politics determined that minimising CO2 was more important than the consequences for NOx. Diesel engines used to run without making ANY NOx. However, because of the political need to reduce CO2, they were modified to minimise CO2 regardless of the consequences for NOx.

Totally separately, if you don't have a particulate filter, the particulates are pretty bad. The type of filter that has been widely used depends on burning off the particulates. It is quite easy to design other kinds, but, AFAIK, this type is mandated by law. And it has major problems.

Petrol (Gasoline) engines are significantly worse with regard to all types of emissions but the clean-up solutions in use work a bit better.

Banning diesels will not turn out well. Banning older diesels instead of fitting them with an effective particulate filter is what has caused the current problems. But there is no way the world's politicians will admit they caused the disaster when they can blame the auto industry. And no way America will admit gasoline is worse than diesel.

Re:Stop using cars at all.

[PPH]

You must live in a urban rabbit warren.

And he has no idea how his food gets to the corner grocery store. Local freight is a very low margin business. It's easy to say 'just use electric or natural gas trucks'. But these represent a huge investment for the businesses involved. And the bicycle/public transportation crowd are going to scream the loudest when their food costs go up 10, 20 or 30%.

Personally, I don't care. I live out in suburbia. And I don't have to shop at the corner bodega. My grocery store is a warehouse, stocked by larger (and more efficient) trucks. And if some local ordinance increases their price, I just drive a few more miles to the next one outside city limits. In the final analysis, this will be the solution. Cities will place increasing restrictions on the activities of those employed or residing there and people and businesses just move out. Seattle is turning into a bunch of $15/hour hipsters trying to make a living selling each other overpriced coffee.