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CO2 Versus NOx and C
2

CO2 Versus NOx and C

CO2 Versus NOx and C

(OP)
In regards to green house gases, how does CO2 compare with NOx?
How does CO2 compare to soot (carbon)?
Many of the EPA mandates to reduce NOx result in higher fuel consumption, which in turn leads to more CO2 emissions.
Is there a net gain or are we looking at a lower percentage of a larger number?
DPF, Diesel Particulate Filters;
How bad is particulate carbon as a green house gas as compared to CO2?
Almost as much fuel is dumped into the exhaust system, one way or another as is used to drive a truck down the road.
This not only almost doubles the CO2 emissions but also converts the particulate carbon into CO2.
I realize that the EPA mandate may not include green house gasses, but in the big picture are we gaining much?

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: CO2 Versus NOx and C

2
NOx and soot are pollutants. CO2 is not.

RE: CO2 Versus NOx and C

NOx and soot have health effects at comparatively low concentrations. Some of the NOx species are water soluble and hence not very environmentally persistent. CO2 in contrast is a greenhouse gas with a long atmospheric persistence, with a natural sequestration half life on the order of 100 years.

RE: CO2 Versus NOx and C

It sounds complicated, but this suggests that NOx is overall bad for the environment:

Wikipedia:
The direct effect of the emission of NOx has positive contribution to the greenhouse effect.[28] Instead of reacting with ozone in Reaction 3, NO can also react with HO2· and organic peroxyradicals (RO2·) and thus increase the concentration of ozone. Once the concentration of NOx exceeds a certain level, atmospheric reactions result in net ozone formation. Since tropospheric ozone can absorb infrared radiation, this indirect effect of NOx is intensifying global warming.

There are also other indirect effects of NOx that can either increase or decrease the greenhouse effect. First of all, through the reaction of NO with HO2 radicals, •OH radicals are recycled, which oxidize methane molecules, meaning NOx emissions can counter the effect of greenhouse gases. For instance, ship traffic emits a great amount of NOx which provides a source of NOx over the ocean. Then, photolysis of NO2 leads to the formation of ozone and the further formation of hydroxyl radicals (·OH) through ozone photolysis. Since the major sink of methane in the atmosphere is by reaction with •OH radicals, the NOx emissions from ship travel may lead to a net global cooling.[29] However, NOx in the atmosphere may undergo dry or wet deposition and return to land in the form of HNO3/NO3-. Through this way, the deposition leads to nitrogen fertilization and the subsequent formation of nitrous oxide (N2O) in soil, which is another greenhouse gas. In conclusion, considering several direct and indirect effects, NOx emissions have a negative contribution to global warming.[30]


I've always 'heard' that NOx is substantially worse than CO2 regarding global warming, however. We would need to read reference 30:

Intergovernmental Panel on Climate Change, ed. (2014), "Technical Summary", Climate Change 2013 - The Physical Science Basis, Cambridge University Press, pp. 31–116, doi:10.1017/cbo9781107415324.005, ISBN 9781107415324, retrieved 2018-11-15

I need to read the IPCC technical summary at some point. Maybe later today, even. It's extra interesting to me because I've been offsetting my airline miles with a NOx capture program located on a fertilizer refinery.

RE: CO2 Versus NOx and C

Frustrating, but for some reason all the links to the IPCC report concerning NOx is giving a 404 error.

RE: CO2 Versus NOx and C

CO2 is the base unit, pretty much every other compound has a higher global warming potential.

NOx depending on how it is included in the compound will be one hundred to ten thousand times worse or more.

Straight up carbon as a solid no problems as a gas. Getting it to stay solid while using it and not bond with O2 harder.

The first stage of site investigation is desktop and it informs the engineer of the anticipated subsurface conditions. By precluding the site investigation the design engineer cannot accept any responsibility for providing a safe and economical design.

RE: CO2 Versus NOx and C

Geo,

Global warming potential means the amount of heat that molecule can trap, but doesn't take into account any other effects? Like the article mentioned above, NOx has the ability to react and leave OH-, which helps break down CH4. After all the costs and benefits are taken into account, is CO2 worse or better than NOx?

RE: CO2 Versus NOx and C

Soot can have a very strong effect on albedo, particularly on snow. Anywhere else it will pretty much be absorbed into soil.

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