Last night on Charlie Rose, some leader in science and/or industry decried the sorry state of the environment with a claim that “The emissions from Henry Ford’s first Model T are still out in the atmosphere.”
Now, I do not doubt that his statement is probably true by the strictest definition. That is, that some molecules from that bygone automobile are still floating around in the air somewhere. But Jesus, probably so are some dinosaur sneeze molecules.
What I want to know is whether the statement is true in the doomsdayish way most layman will interpret it. That is, that once auto emissions are poured into the atmosphere, there is no natural mechanism that will convert or render any of them harmless, even after one hundred years’ time. As sympathetic as I am to the environmental movement, I have a hard time believing this. And, if it is not true, I think Mr. Bigtalker was being very disingenuous to the viewers.
CO[sub]2[/sub] will be removed by photosynthesis. SO[sub]2[/sub] will eventually fall to earth as acid rain. The rest I’m not sure about. In all, however, this looks like one of those statements that sounds impressive, but really says nothing important. Like you said, there are probably some molecules from Neanderthal man’s farts still floating around.
The statement is pretty much bullshit, and someone should have called them on it. It’s only true in the sense that, like you say, there’s a chance that some molecules may be around. I mean, simply because there are so many molecules which are produced by even a breath that there’s always a non-zero chance of some lingering. There’s nothing emitted from car exhaust which should stay in the atmosphere indefinitely - as stated, CO2 can be removed biologically and SO2 will come down as acid rain. NOx will also form acid rain, hydrocarbons will react or combine or break down naturally, heavy metals will precipitate, particulates will fall out or precipitate in rain…really, nothing is going to stay up forever.
If I recall correctly, one figure I’ve read is that molecules from car exhaust can damage ozone molecules for about fifty years before they break down themselves. The first Model T’s were produced in 1908 - if the above figure is accurate the statute of limitations has passed on them.
I think you and FRDE are getting the effects of auto exhaust mixed up with the effects of CFCs. Chlorofluorocarbons can and do rise up to the Ozone layer (50 miles + or so above the earth) The chlorine can and does react with the ozone molecules over and over again. This is why Freon was banned. I have heard the 50 year number used many times when discussing the damage done by CFCs and the ozone layer. I have never heard a claim that NOX causes damage to the ozone layer.
Looking at the Wiki article on the ozone layer it mentions Nitrous oxide as being another chemical that damages the ozone layer. However when discussing automotive exhaust pollutants you must keep in mind that oxides of nitrogen are not produced until the combustion temps reach 2500 F. With its rich mixtures, and low compression ratio (3.7:1 IIRC) I doubt that any model T anywhere ever spat out any oxides of nitrogen.
So forget about NOX from a Model T.
(Nitpick) Well, in fairness some NOx is produced at lower temperatures, it’s just that the reaction rate curve does not skyrocket until you get to the temperature range you suggested.
Agreed, the amount is >0 but not by much. On the charts I use in class the rise is almost digital. From almost nothing to Holy crap in a vertical line. The cross over point is always shown at 14.7:1. Is that correct, or did the guys that wrote my chart take a shortcut or three?
True or not, the idea is used to give the impression that all auto emissions since the Model T are accumulating in the atmosphere, and from that, policy decisions about auto use and emissions standards must keep that in mind. it’s an example of bad science used for political purposes.
Well…I think we’re sort of talking about 3 things here - the temperature dependence factor, the compression ratio (which you mentioned earlier with respect to the Model T) and the stoichiometry. In terms of stoichiometry (which from the 14.7:1 is what I’m guessing we’re talking about) NOx does shoot up as the mixture is leaner - to a point. I mean, at some point combustion becomes so diluted that the temperatures decrease, but then we’re not holding all things equal.
You forgot one from the era of the Model T: Some form of lead oxide, since lead was used as an octane booster for many decades.
Some folks are claiming that carbon released into the atmosphere today is going to stay there, even if one does “carbon off-setting.” (i.e. trying to minimize the damage you’re doing is somewhat pointless)
Many enviromentalists have an irrational hatred for the automobile and are laboring under the mistaken impression that if we totally ban the auto, most of our environmental problems will soon go away. This is simply not the case. Banning the auto would reduce certain pollutants, it’s true, but you’ll be shifting the pollution to another form, with unknown consequences.
