Euro 4 comlaint

can this be sold in the us which has higher emisson standards ?

Just how did .05g/m NOx for light-duty diesel become the law of the land? So weve succeded in eliminating a viable fuel conserving engine option from the continent, while off-highway and marine diesels are allowed to burn high sulphur fuel, neutralizing any gains made.

Why can't we get these cars in the US again?

Here in America there's a myopic view of tailpipe emissions. Everything but CO2 is demonized when it's arguably the CO2 that's most threatening to the biosphere.

People are always going to be more concerned about their lungs than about a distant, slowly-evolving problem which may not even affect them directly. NOx matters because people care about smog - for good reason.

What I don't understand are people who dismiss that as being important.

NOx matters because people care about smog - for good reason.

If smog is the concern, then reducing NOx is not the answer. Reductions in ambient NOx levels has the potential to increase ambient ozone levels (smog) in urban locations.

Right - let's put as much NOx in the air as possible -- then it will eventually be pure!

I hope you see the logical problem with "weekend effect" way of thinking.

Actually, the logical problem is yours.

The implications of the Weekend Effect are that NOx reductions beyond a certain point will do more harm than good in terms of air quality, ergo the money that would otherwise be spent on that particular pollutant would best go elsewhere (VOCs, or even CO2, if you like).

Point of Diminishing Returns, see?

Actually, the logical problem is yours.

Great retort there. "I know you are..."

The implications of the Weekend Effect are that NOx reductions beyond a certain point will do more harm than good in terms of air quality, ergo the money that would otherwise be spent on that particular pollutant would best go elsewhere (VOCs, or even CO2, if you like).

Uh huh. Where exactly is that "certain point"? Spell it out in detail. What's the precise level?

Point of Diminishing Returns, see?

No, I see you latching onto unproven science, yet don't apply the same standard to your position on climate change. To claim "diminishing returns", you'd need to have a detailed cost/benefit analysis, plus projections in increased emissions due to population and VMT increases. That's all assuming that one can accept that human life has a dollar value.

Have concurrent reductions of VOCs and NOX been effective only on weekdays?

No. Concurrent reductions of VOCs and NOX have been effective at reducing ozone levels on all days of the week, including weekends. Figure 1 shows trends for weekdays and for weekends at three locations in the SoCAB. Both weekdays and weekends show substantial improvements at all three locations. On average however, ozone concentrations have declined slightly more slowly on weekends than on weekdays. The trends for other sites in the SoCAB show similar results.

Are NOX emission reductions only relevant to ozone?

No. Secondary products of NOX emissions contribute to ambient levels of several pollutants in addition to ozone. Some of these pollutants, such as fine particulate matter (PM10 and PM2.5), nitrogen dioxide (NO2), nitric acid, peroxyacetylnitrates (PANs), and some mutagenic nitro-polycyclic aromatic hydrocarbons are known to be detrimental to human beings, to the environment, or to both.

For some of these compounds, data are scarce and specific changes attributable to reductions in NOX emissions are difficult to identify. However, routine measurements of NO2 show that annual maximum concentrations at 15 sites in the SoCAB were reduced by 32% to 64% from 1980 to 1998. The Basin did not attain the federal annual average air quality standard for NO2 until the mid-1990s. In addition to NO2, particulate nitrate, nitric acid, PAN, and other secondary products of NOX emissions have declined in the last 20 years in the SoCAB.

Because multiple pollutants are affected by NOX reductions, they must be considered as part of an overall strategy for attaining all air quality standards and reducing air toxics exposures. Nevertheless, the remainder of this summary primarily considers the ozone weekend effect and its relevance to NOX reductions as an ozone control measure.

more here:
http://www.arb.ca.gov/aqd/weekendeffect/arb-final/web-executive-summary.pdf

Pizmo:

I don't have exact numbers, no. But the Weekend Effect was acknowledged at the DEER 2005 Conference. (PDF file, see Implications and Questions) This presentation includes future emissions projections. A Google search for DEER 2005 Weekend Effect will bring up some other relevant sites. And there's this article as well.

If this study is correct further NOx reductions won't actually do any good, unless the other smog precursors (like VOCs) can be reduced also.

And my position on climate change angers people on both sides of the political aisle. I'm used to that by now.

Guess I don’t.

Well, then I can't help you. You take your approach to its logical end, then you must keep increasing pollution to get cleaner air, and progressively decreasing pollution makes the air dirtier. That makes no sense whatsoever.

I’m not advocating increasing NOx emissions, so you’re putting words in my mouth. The logical solution is to reduce VOC and CO emissions relatively much more than NOx, exactly inverse of what the current regs do.

If it's so logical, why do CARB and the EPA disagree with you?

You take your approach to its logical end, then you must keep increasing pollution to get cleaner air, and progressively decreasing pollution makes the air dirtier. That makes no sense whatsoever.

I'll try again. Based on these studies, you need to REDUCE VOCs and CO relatively more than you REDUCE NOx. In other words, you can't go willy-nilly reducing these ozone precursor emissions. CARB/EPA apparently lumps all "ozone precursors" into one and expects that arbitrary reductions will equate to less "smog". The mechanisms of ozone formation of VOCs and NOx are COMPLETELY different.

If it's so logical, why do CARB and the EPA disagree with you?

I've been in the environmental field long enough (over 20 years) to know that CARB/EPA frequently come out with illogical regulations.

Never heard of him.

So?

Gosh! I get to comment amidst a flame war, so no one will read my acerbic comment except the combatants.

It would seem that GM actually is implementing a 1950s plan that got reworked with the 1970s oil crisis.

Meanwhile, the X Prize remain up for grabs and the plug on the BioSaab is still glued shut. Look at it as a metaphor.

Their regulations are "willy nilly"? Is that even remotely accurate?

You be the judge - the CARB LEV II and EPA Tier 2 regs mandate nearly an order-of-magnitude reduction in NOx emissions and essentially ZERO reductions in CO emissions (http://www.dieselnet.com/standards/us/light.html), yet there are still areas of the U.S. that are in "serious" non-attainment with the CO NAAQS (http://www.epa.gov/oar/oaqps/greenbk/mapco.html).

Does that sound like an effective regulation to you?

The question comes down to why you and they disagree. What's the reason?

Well, besides the weekend effect implications, what I learned in grad school.

Here's a quote from a textbook used in one of my grad courses:

"…The atomic oxygen produced by the photolysis of NO2 is very reactive and readily combines with O2 in the air to form O3. In the presence of NO, however, the O3 will immediately decompose, regenerating the nitrogen dioxide. This nitrogen dioxide photolytic cycle is summarized in the following three reactions.

NO2 + hv --> NO + O

O + O2 --> O3

O3 + NO --> NO2 + O2

Hence, while the presence of NO2 is required to form O3, the nitrogen dioxide photolytic cycle by itself does not generate net ozone, and cannot explain ozone accumulation….

...ROG [VOC] reductions (with constant NOx) always lead to a slowing of the ozone production process and lower peak ozone concentrations. NOx reductions (with constant ROG) can lead to a speeding up of the ozone process, and can increase or decrease peak ozone values depending on the ROG-to-NOx ratio.

Thus, whereas ROG control is never detrimental, NOx control can be detrimental, particularly in the central cores of urban areas...."

Source: Air Pollution Control, A Design Approach; Cooper, D. C.; Alley, F. C.; Third Edition, pages 595 and 600

I actually have a great deal of respect for EPA scientists, but the regs aren't written by them - they're written by regulation writers. It's my concern that a lot of politics gets involved at that point and "dilutes" the science.