NOx is what makes the brown crap that floats over our cities.
I've seen the same brown cloud hanging over London and other cities in Europe.
You can whine "yeah but" all you want, but NOx *IS* a serious pollutant. Your TDI exceeds the output for any gasoline powered car or light truck or SUV.
I like my TDI as much as anyone, but I'm realistic about what it does. CO2 is a greenhouse gas and its importance as a pollutant is only now becoming as well understood. NOx is bad stuff. Ain't no two ways about it.
Let's compare two incomparable vehicles, A TDI wagon and a humongous V8 powered Excursion, probably one of the most hated SUV's on this forum. Keep in mind that the Excursion holds more stuff, people and can tow a big boat
Just for comparison from the EPA test data:
2003 Jetta Wagon TDI test NOx = 0.6
2003 Excursion test NOx = 0.24
2003 Jetta Wagon TDI test HC = 0.02
2003 Excursion test HCHO = 0.0016
The CO2 level is directly related to the fuel consumption. It is only related to the mass of fuel consumed per distance driven. A gas powered Corolla automatic gets about the same mileage as a TDI automatic Beetle, so it will get about the same CO2, less NOx, less HC and so on and it is a comparable vehicle.
SUV killers we are not.
Originally posted by nh mike:
Our TDIs emit FAR less CO2, CO, and HC than any SUV (or pretty much any gas car) - especially a biodiesel powered TDI. The EPA considers diesels "dirty" because they focus almost entirely on NOx and PM, which is simply ridiculous.
Europe is focussing on reducing CO2, HCs, and CO, because those emissions are the most important by far. In the US, the EPA almost completely ignores CO2 emissions, and has set very low limits on NOx and PM, with the only possible reason being to simply kill diesel vehicles. The EPA's limits are sat as if NOx and PM are the most important emissions, which they clearly aren't. NOx and PM are only of concern in big cities in which everyone drives their own car rather than using public transportation. That's why Europe isn't particularly concerned about NOx and PM - in their big cities, they have decent public transportation, and people actually use it. In the US, public transportation is almost considered a sin. Take Boston for example - they're spending bazillions on the "Big Dig" to essentially just encourage people to continue not using public transportation. Why not instead spend a fraction of that on extending the T (train) system further out, so people wouldn't have to drive into the city itself to use it?
IMO, the EPA's focus on NOx and PM rather than CO2 is also because of our government being heavily influenced by corporate (especially oil) interests. It's in the interest of the oil companies to eliminate light diesel vehicles from the US market (since they're more fuel efficient, and would therefore consume less oil). Thus, the EPA sets ridiculously low limits on NOx and PM (the emissions of which almost don't matter at all for those of us who don't live in big cities), which just further discourages manufacturers from selling diesels in the US.
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