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"...I wonder about their ability to meet emission standards when VW and many others have failed." It will have to or it won't be certified. Every light-duty diesel vehicle line certified in the U.S. is subject to months of extensive additional testing and has since the NOV was issued to VW in September 2015. The additional testing is conducted to ensure the vehicles' certified emissions are representative in all "driving cycles and conditions that may reasonably be expected to be encountered in normal operation and use."
Those are ambient levels to which all sources of PM2.5 and NO2 contribute.
According to EPA, ambient PM2.5 levels have dropped by an average of 42% and ambient NO2 levels 47% between 2000, shortly before the end of the study period (2004), and 2016. That should mean that air pollution-related cancers should be dropping like a rock, shouldn't it?
@kalendjay, just to be clear, N2O (nitrous oxide) is the powerful greenhouse gas to which you're referring and is not considered "NOx". NOx = NO (nitric oxide) + NO2 (nitrogen dioxide). Neither NO or NO2 are considered greenhouse gases; atmospheric lifetimes are much too short.
I agree this is a highly biased study. Even diesel-hating CARB has lower upstream GHG emissions for ULSD than gasoline (per MJ) in its "Low Carbon Fuel Standard" regulation, and biodiesel/renewable diesel from crop oils has lower upstream GHG emissions than ULSD, even with the controversial indirect land use change included.
In the first place, that study was done in India. Not relevant to U.S./Canada. In the second place, gassers have been shown to have much high PM and PM precursor emissions than diesels. I'll take a little higher NOx emissions over those any day. Thirdly, Tier 3 diesels in the U.S. have been shown to have NOx emissions near SULEV levels in "driving cycles and conditions that may reasonably be expected to be encountered in normal operation and use." This has been confirmed by the ICCT itself: ("USA" - "Tier 3") Fourthly, even in this study, CO emissions from the I20 gasoline are 74 times higher than the CO emissions from the I20 diesel in the "independent" real driving tests. Why are high NOx emissions any worse than high CO emissions?
The study was funded by U.S. National Science Foundation. Grant Number: 0967353 and Norwegian Research Council. Grant Number: 190940, according to the paper.
There was a study conducted in 2013 that analyzed the full life-cycle impacts of electric and diesel transit buses ( In only 8 states were the electric buses superior to the diesel buses, and that was with regular petroleum-based diesel fuel. B20 clearly would be better still. Since OTR trucks cross many states, there are probably no scenario in which electric trucks overall would be superior to diesel trucks running B20 with respect to GHG emissions or damages to public health and the environment.
@mahonj, DEF (urea solution) usage will likely increase in these circumstances. It's also probably at least one reason why manufacturers cut corners in the first place - to allow a tank of DEF to last through a full service interval without placing a huge DEF tank in the vehicle. BMW is using a combination of a LNT (called a "passive NOx adsorber" - "PNA") and SCR for their diesel cars in the U.S. The PNA adsorbs NOx during engine start-up or periods where the SCR isn't sufficiently warm to convert the NOx to N2. The NOx is desorbed from the PNA when the SCR is sufficiently warm. The U.S. BMW diesel cars/SUVs have been shown to have extremely low NOx emissions.
The movement for a blanket "diesel ban" is off-the-chart foolishness. Most likely, diesel will be replaced by gasoline, mostly GDI at that. GDI has been shown to have higher CO, NMVOC, and PM/PN than current Euro 6 diesels, not to mention unregulated air toxics and higher emissions to refine gasoline compared to diesel fuel. Even if GDI generally has lower NOx emissions, there's a trade-off even with that which doesn't seem to be taking into account. Ambient NO2 and PM nitrate (nitrate aerosols) may be reduced, but ozone and organic PM (SOA) may increase in urban locations. According to the European Environmental Agency, ambient NO2 levels have been steadily declining anyway. If Europe is really having as much trouble with ambient NO2 levels as has been reported, it needs to adopt new certification test procedures to include driving cycles and conditions that may reasonably be expected to be encountered in normal operation and use. The RDE test cycle may be a significant step in this direction.
Looking at it another way, regulators should be/should have been focusing on VOC emission reductions more than NOx emission reductions instead of the other way around.
Another aspect that's generally not considered with volatile fuels like gasoline and ethanol is the waste through simple evaporation of the fuel. According to EIA (, 385 million gallons/day of motor gasoline are consumed in the U.S. That's about 140,500,000,000 gallons of gasoline consumed by the U.S. vehicle fleet per year. According to EPA, 49.7 grams of VOCs are produced per million BTU of gasoline (~5.7 g/gal); 7.9 g VOCs are produced per million BTU of diesel (0.95 g/gal) (EPA, "Draft Joint Technical Support Document: Proposed Rulemaking for 2017-2025 Light-Duty Vehicle Greenhouse Gas Emission Standards and Corporate Average Fuel Economy Standards." (Table 4-12, page 4-42 [366 of 479])). 140,500,000,000 gallons X 5.70 g/gal = 882,770 tons of VOC WTP per year from the fuel gasoline. Hypothetically switching the light-duty vehicles in the U.S. to diesel could reduce WTP VOC emissions to (140,500,000,000 gallons X 0.95 g/gal) = 147,129 tons/year. 882,770 tons - 147,129 tons = 735,640 tons/year or almost 237,300,000 gallons/year of gasoline not evaporated as VOC. This does not take into account the demonstrably higher VOC emissions of gasoline vehicles during vehicle refueling, diurnal + hot soak, and running loss. That's almost three supertanker ships full. Not only is this a colossal waste of a valuable resource, VOCs contribute to ground-level ozone production and secondary PM2.5 (secondary organic aerosols).
It would be nice to know what emission rates of other criteria pollutants were. Another recent report extolling the virtues of CNG trucks in Southern California (Johnson et al. "Ultra-Low NOx Natural Gas Vehicle Evaluation ISL G NZ") showed very low emissions of NOx emissions relative to diesel trucks with SCR, but higher emissions of all other tested pollutants (CO, NMHC, PN, NH3). The trade-off of lower NOx emissions for higher emissions of all other pollutants is questionable.
@mahonj, Thank you for your response. I assumed that the EEA report was valid, but it's so inconsistent with what I've been hearing about air quality in urban locations in Europe, something has to be hyped, one way or the other. It almost sounds in some articles like the air is barely breathable in many city, almost as bad as Beijing, China! Again, if those EEA data are representative of the current air quality in Europe, they are actually much cleaner than most U.S. cities, especially with respect to ground-level ozone (an especially perplexing air quality problem in the U.S.) I don't disagree about start/stop systems which are consistent with some degree of hybridization. It should be noted though that petrol engines have high PN emissions at each start-up, cold or hot.
@mahonj, According to European Environmental Agency's air quality assessment report (Air quality in Europe — 2016 report, EEA Report No 28/2016), Ireland has very CLEAN air generally, really the cleanest in Europe based on overall criteria pollutant monitoring data. It appears that there are only two monitors in Ireland in that monitoring system, but one of them appears to be in Dublin. According to that report, ambient levels of all criteria pollutants, including NO2 and PM10/PM2.5 are all far below EU's ambient air quality standards, and even well below WHO air quality guidelines. I can tell you as as air pollution meteorologist that most metropolitan areas in the U.S. would be ecstatic with those air quality data! Is EEA embellishing its accomplishments with respect to air quality there?
Why does the EU seem to be losing its mind over high real-world NOx emissions from diesel vehicles, but seems to be completely unconcerned about high real-world CO and PN emissions from petrol vehicles, especially GDI (well above the Euro 6 regulatory limit)?
It should be noted that life on terrestrial earth would not be possible without particles; they serve as condensation nuclei (CCN). Precipitation would not be possible without CCN.
@Change - yes I know the energy and emissions I posted are WTP. I was trying to show that the energy to produce electricity was far more than producing gasoline or diesel, even if you consider the far higher "mileage" of EV. Have you had a chance to look at the GREET model? It takes all emissions, WTP, PTW, and emissions produced in manufacturing/recycling a vehicle, into account. It also takes tar sand petroleum production into account. Do you dismiss the AEA study (
Regarding the "spewing of cancer particles" comment, the 2017 Cruze diesel is officially certified to have PM emissions of 0.2 mg/mile (0.0002 g/mi - The 2017 Toyota Prius Eco is officially certified to have PM emissions of 0.4 mg/mi (0.0004 g/mi - That tired old myth needs to be buried once and for all.
@SJC - fully agree. I would only add that liquid fuels can be created in many ways also, e.g., renewable diesel which has extremely low upstream emissions ( DME from biomass has negative GHG in some scenarios. @JMartin - you may be right. My concern is that a significant market penetration of EVs in high coal grids like the Midwest will almost ensure that coal generation will remain, even if the marginal generation is non-coal.
You're right, I still don't see how an EV that uses "fuel" (electricity) that takes over 1.2 million BTU to make 1 million BTU of electricity can negate a diesel vehicle which takes less than 250,000 BTU to make 1 million BTU of fuel (diesel), even if the EV gets 3 times better "mileage" than a diesel vehicle. By the way, it takes even more energy to produce electricity in the Midwest grid which is the topic of discussion here. I invite you to download the GREET model (just requires registration (free)), "Fuel-Cycle Model" and "Vehicle-Cycle Model" available at Here are screen captures of WTW emisisons of gasoline (GDI - E10), diesel (ULSD), and electric (current U.S. mix) that I get: (emissions from vehicle manufacturing/recycling) Let's see if you get comparable emission factors.
Here is the upstream (well-to-pump or mine-to-plug) emissions of gasoline/diesel/electricity per million BTU in the current average U.S. mix (which is down to about 30% coal generated per EIA) according to GREET (includes well drilling/infrastructure). Energy is BTU per million BTU of product produced, and emissions are in terms of grams/million BTU of product: Parameter.........Diesel..........E10…………..Electricity Energy………………………….232,343……......306,459……...1,214,154 VOC…..............9.617..........31.483………………18.230 CO...............24.759..........29.172………………79.331 NOx..............35.583..........44.629………..108.283 PM10..............3.067...........4.394…………..27.912 PM2.5.............2.208...........2.745…………..10.910 SOx…………………….………….27.264….………….……..41.699……….252.965 GHG………………..………………21,384………..…………….22,845……….144,427
I've seen that claim, and it's in GHG emissions, not the conventional pollutants. They are FAR higher in 100% coal-generated electricity, at least according to GREET.
I fundamentally disagree that EVs charged in a grid that's over 50% coal-generated electricity has lower environmental damages than gasoline vehicles. It doesn't really matter that an EV can drive 24 miles or whatever on what it takes to make a gallon of gasoline, because electricity in those generation mixes produce much more conventional pollution like NOx, PM2.5, and SOx than emissions produce in the production of gasoline. Again, it's not just about GHG. The paper I linked ("Are There Environmental Benefits from Driving Electric Vehicles? The Importance of Local Factors") essentially updates the same conclusions reached in a 2010 study by the National Academy of Sciences ("Hidden Cost of Energy: Unpriced Consequences of Energy Production and Use"). Based on Argonne National Laboratory's GREET model and published damage factors, an EV charged with electricity generated in the Midwest grid would cause 75% more health/environmental damage than an equivalent gasoline vehicles, and over twice the damage of a (compliant) diesel vehicle, from a full life-cycle perspective. I agree that BEV is beneficial in clean grids like California, but its dubious that there are any health/environmental benefits in the current Midwest grid.
According to the latest data from EIA (Q3 2016), over 50% of electricity generation in the states mentioned was from coal. There's still a long way to go before it becomes clean enough to promote BEV there. It's not just about GHG emissions. There are also VOC, NOx, PM2.5, and SOx emissions, all of which cause damage to public health and the environment, some more than others.