On a hunch, Google reports this as Non Methane Organic Gas as feed stock with NO(x) for ozone:The very small units are consistent with the risk from the highly reactive ozone.

Bob Wilson

 

It is the concentrations and smog of big cities that is the problem. Cars aren't running equidistant from each other across the world. Canada is a very large and beautiful country, but what some people notice is the sickly green haze hovering over the raised Gardiner Expressway in downtown Toronto during the Summer.

BTW, for the record, Honda Civic Hybrid (2006-) is rated at Tier 2 Bin 2 for emissions (currently the next-best rating to zero emissions). Also important to the low-level ratings is that they must maintain low levels over the lifetime of the vehicle. Poorer graded cars have tolerance for getting sloppy as they age.

 

While NOx and hydrocarbons (HC also called NMHC. HC-NM, NMOG, VOCs, and a host of others) are required to produce ground-level ozone (the primary constituent of "smog"), NOx has the ability to both produce or DESTROY ozone, depending on ambient conditions (i.e., NOx readily reacts with ozone under certain conditions). Anthropogenic VOCs on the other hand, do not react with ozone under any conditions, so they have no ozone-destruction properties.

To put it in as simple of terms as possible, you need both NOx (NO + NO2) and non-methane hydrocarbons (VOC) to make ozone. CO works also. Lot of NOx, little VOC = ozone destruction and nitrate deposition. Lot of VOC, little NOx = peroxide and organic aerosol formation (the "smoke" in the Great Smoky Mountains). Lot of NOx, lot of VOC = lots of ozone, lots of organic aerosol (PM), lots of PANs (peroxyacyl nitrates, the stuff that makes your eyes water). Whether adding NOx makes ("NOx limited regime") or destroys ("VOC limited regime") ozone depends on the amount of VOC you have. Essentially ALL urban and suburban regions in the US are VOC limited. That's why they tell you to fill up in the evening or early in the AM -- those fugitive emissions are basically instant ozone and PM (in the really nasty nano and ultrafine fractions, no less) during the day. You cannot address ozone by addressing only NOx.

As far as emissions from “clean diesels” are concerned:

“...Diesel engines equipped with the latest emission controls emit lower levels of deadly fine particles than gasoline engines, according to various trade groups in the automobile industry.

'Diesel particle filters appear terrific at eliminating virtually all diesel particulate matter emissions,' Clean Air Watch President Frank O'Donnell said Nov. 27.

In the tests by the Association of Emissions Control by Catalyst, diesel engines with emission controls also produced about one-tenth of the carbon monoxide emitted by gasoline engines and less than half of the hydrocarbon emissions...."

http://www.greendieseltechnology.com...p?ID=418&link=, also referenced on slide #36 page “18 of 51” in http://www.beyondcompliance.net/pdf/..._07_Update.pdf

 

I see a lot of words and selected qouting. However I do not follow your post.

I have to believe that the folks at CARB and the EPA are experts in the field of air pollution and elements that cause SMOG. So my question would be how does the elements the EPA test for and the numbers of the vehicles I listed interact in relation to air pollution?

The UK site I linked explains the lements much more clearly than you did, and the EPA tests for lements not listed in the UK site.

I keep hearing that NOx is not bad from the pro diesel crowd, yet I notice the EPA and the EU standard clamping down hard on it. So somehow it just doesn't quite add up for me. Then you talk about elements not listed in the way you discuss it on the EPA tests, so maybe a simple translatin of all the lements the EPA test for in your discussion would be good. Otherwise your explanation is nothing but a bunch of terms I'm not familiar with and unable to correlate which vehicles are bad or not.

Reason I ask is that we want to repalce one of our vehicles in the household in the next couple of years, and I would like to get something that achieves very good fuel mileage, have very good air pollution stats, good performance, larger vehicle (station wagon/crossover/SUV type), luxurious and reliable. So far both diesels and hybrids I have seen have come up very short of my expectations.

 

If you don't believe me, here are many links which address the complex NOx/VOC/ozone issue:


http://www1.eere.energy.gov/vehicles...eer_lawson.pdf

http://www.arb.ca.gov/aqd/weekendeff...r_wspa_com.pdf

http://www.raqc.org/ozone/Workshop/O...g%20Lawson.PDF

http://www.biodieselmagazine.com/art...51&q=&page=all

http://www1.eere.energy.gov/vehicles...eer_lawson.pdf

http://www.aei.org/publications/pubI...pub_detail.asp

http://www.heartland.org/Article.cfm?artId=18973

http://www.greendieseltechnology.com...p?ID=403&link=

http://www.greendieseltechnology.com...EER%202006.pdf


EPA itself acknowledges that reducing NOx in VOC-limited areas (at constant ambient VOC levels) will actually make ozone worse in those areas (and urban areas are where most of the ozone NAAQS nonattainment occurs and where a lot of people live):


…It should be noted, however, that the potential exists for a few localized areas to actually experience slight increases in ozone concentrations as a result of NOx emission reductions....
EPA Final Regulatory Impact Analysis: Control of Emissions of Air Pollution from Highway Heavy-Duty Engines, http://www.epa.gov/otaq/regs/hd-hwy/1997frm/hwy-ria.pdf (page 119)

…When NOx levels are relatively high and VOC levels relatively low, NOx forms inorganic nitrates (i.e., particles) but relatively little ozone. Such conditions are called “VOC-limited.” Under these conditions, VOC reductions are effective in reducing ozone, but NOx reductions can actually increase local ozone under certain circumstances.…
http://www.epa.gov/otaq/regs/nonroad...nepreamble.pdf (page 33)

…Under these conditions, VOC reductions are effective in reducing ozone, but NOx reductions can actually increase local ozone under certain circumstances. Even in VOC-limited urban areas, NOx reductions are not expected to increase ozone levels if the NOx reductions are sufficiently large.…
http://www.epa.gov/otaq/regs/nonroad/420d07001chp2.pdf (page 2-41)


…In urban areas with a high population concentration, ozone is often VOC-limited….
…Due to the complex photochemistry of ozone production, NOx emissions lead to both the formation and destruction of ozone…The terms “NOx disbenefits” or “ozone disbenefits” refer to the ozone increases that can result from NOx emission reductions in these localized areas….
http://www.epa.gov/ttn/ecas/regdata/...iachapter2.pdf (pp 2-1 - 2-2)


More:

…The extremely important implication of this scientific finding (AN11) and findings from other studies is that because of the ozone-destruction effect of NOx under VOC-sensitive conditions and the widespread occurrence of such conditions (e.g., within intensely urbanized areas), air quality managers should view NOx control with caution….
Southern Oxidant Study (SOS), http://www.ncsu.edu/sos/iii.html

Slide #33 of this presentation suggests the current regulations won’t make ozone any better in urban areas.

I’m not suggesting that NOx isn’t a pollutant and shouldn’t be regulated. My point is that the approach taken by the regulators for the current emission regulations (e.g., Tier 2) isn’t supported by the current science.

 

Not a question of not believing, rather not following.

VOC seems to be caused by other elements,?? Yet how do we know what the VOC level is in an area and relate to NOX and ultimately air pollution?? And why is NOX so heavily regulated in the new EU adn EPA specs?

 

Here's another fuel economy comparison including the Jetta TDI and Prius:

AutoWeek, April 2006

It's interesting that the Jeep, Corvette, and Accord Hybrid all got very close to their (pre-2008) EPA highway ratings on the test run, while the Prius got significantly less, and the Jetta got significantly more.

 

That is interesting. Perhaps it was the relatively high speed (75-80 mph) of the test that influenced the results? There seems to be plenty of evidence that a diesel is a great choice for higher (70+) highway speeds.

At 55 mph the smart money is on the Prius.......

 

Their 42 MPG results are consistent with:

Factor in the cold weather, the potential effects of over fill of the engine oil and tires filled to just 32 psi and these results are quite consistent.

In January 2008, I drove from Huntsville AL to Columbia SC and back going from 15F-38F-18F in no wind conditions, across a winter high pressure system. What I found is temperatures below 32F delivered just under 50 MPG at 65 mph and above 50 MPG at higher temperatures. We later checked and mileage fall off was directly proportional to the air density. There are driving profiles that the Prius does not perform well and anything over 65 mph and cold weather, colder than EPA test conditions, are key.

Bob Wilson

 

Bob I'd hafta go back to college to understand your graph. Are you saying diesels do perform well at higher speeds and do perform well in the cold?