Diesel vs. Gasoline (polution related)

A recent news clip showed that the city of Paris (fr) banned 1/2 the cars to get smog under control. Good thing it worked.

Here is the link: http://www.theguardian.com/world/2014/mar/17/paris-stops-car-ban-one-day

Two short clips from it is:

I am also under the strong assumption that diesel is the preferred motor fuel over there while in the US Gasoline is.

If Paris had cars that used gasoline primarily, how would this be different?

I know in the US where you are required for emission inspection, usually, if not always diesels get off easy, and sometimes have no requirements. I also know that there is this comparatively new line of ‘clean diesels’ - which I know very little about. I also know that so much has been done to reduce emissions from gasoline cars, including the catelitic converter, oxygenated fuel ect.

So would a city environment, such as Paris, fair better with a primary fuel of gasoline? Expanding that is gasoline a better motor fuel for congested mega cities with air pollution issues?

Of course, they have reversed the ban already:

Burning diesel produces significant amounts of particulate carbon, as evidenced by the black smoke you might see on an accelerating diesel truck. On the other hand, burning gasoline produces a larger number of nasty gases. Reformulated gasoline produces a byproduct that not only reduces fuel economy, but poisons groundwater.

There is a preference for diesels in much of Europe, due to better fuel economy and lower cost (diesel requires less refining than gasoline) per liter.

I find it odd that a city that has as many smokers as Paris would be so concerned about particulate matter.

As to the specific question-- would Paris fair better with primarily gasoline? Not necessarily-- You might reduce the number of asthma related illnesses, but would likely see increased rates of other diseases.

Not noticeably - and gasoline is a much worse motor fuel in terms of overall environmental impact.

Counterpoint, I believe you are talking about MBTE (I think that is what it is called), it has been banned in many places and replaced usually by ethanol which does not that the groundwater issue - actually people are known to add ethanol intentionally to their wwater for drinking purposes :wink:

Close-- Methyl Tertiary Butyl Ether (MTBE)-- but you are apparently correct in that it has largely lost favor.

Diesel and gasoline result in different kinds of pollution. Traditional diesel is bad as far as particulate and oxides of nitrogen (NOx, which leads to smog). In the US, newer diesel vehicles are much better than diesel even 10 years ago, in part due to the reduced sulfur content in diesel fuel allowing better control technology, but I believe that it’s still worse than gas for PM and NOx.
Gasoline results in VOCs, which also result in smog.

Gasoline and diesel both pollute groundwater from leaking tanks. MTBE (or related oxygenates) is merely a constituent of gasoline people were particularly alarmed about. It’s potentially carcinogenic, so it’s a health concern. The bigger issue is that it’s highly mobile in groundwater. If a gasoline tank with MTBE leaks, the MTBE will race out in front of the gasoline plume (with all it’s carcinogenic benzene goodness). So you have people encountering MTBE faster than they would encounter gasoline. And yes, it’s largely out of the supply chain now and replaced with ethanol.

It’s also not just the diesels. Until the EU-harmonized emissions regulations came into force in the 1990’s, gasoline cars without catalytic converters or other basic pollution controls were still sold in many European countries, I believe France included. Even after that, the EU standards were much lower than the US ones until relatively recently.

I think the bottom line is that the problem has been with Europe’s lax attitudes towards smog, not their greater usage of diesels (although the two are likely related). The emissions standards that have been put in place in recent years should help the problem considerably, both for diesel and gasoline cars, but for now there’s still a lot of older cars on the road. Studies in the US done during the 1990’s showed that the largest contributors to ongoing smog problems were STILL cars built before the Clean Air Act, even 20+ years on. These things take time.

ETA: Also, that’s not even mentioning motorcycles and scooters, which account for a lot more of the traffic in that part of the world and have also been basically unregulated until recently.

Didn’t the air quality in L.A. get cleaner recently, when compared with the 1950s and 1960s? I remember that being in the news a few years back.

Also, is there a place that lists the different cars and the tons of CO2 they emit per year? I’m wondering about how a given car compares between its gas engine vs. ots diesel engine. I searched briefly but couldn’t find that.

The headline was that Cleaner cars have reduced some Los Angeles air pollution levels by 98%, but that’s an oversimplification. “Certain vehicle-related pollutants” is a useless term. Overall, pollution is down significantly in Los Angeles, per South Coast AQMD. (The last two columns are the easiest to understand.) Ozone concentrations on the worst days are down to about a third of what they used to be in the 1970s, so things are much better. LA is a basin that will always have air quality problems. There are too many people in a basin that traps air. The reductions they’ve achieved are impressive.

The EPA Fuel Economy Site is cumbersome, but you can find the tailpipe greenhouse gas emissions. I’m not aware of one that covers other major pollutants. The Emfac model might show what you want, but it comes with a learning curve and won’t show differences by model, only classification (gas, diesel, bus, etc…).

CO2 is not considered a pollutant. I’m not denying that we are learning the basics of how we can terraform a planet through the release of CO2 into the atmosphere for global temperature control, but that is a separate issue then pollution in inner cities.

But what you ask is pretty easy to calculate based in mpg and a correction factor for diesel mpg (which I believe diesel would have a slight penalty because the fuel is more carbon intensive and less hydrogen intensive then gasoline)

In the UK the annual tax on private cars is based on emissions of CO2 per km and all new cars quote this figure.

In answer to Bullitt’s question diesel vehicles generally do much better than petrol engines.