Happy Earth Day! (2-Stroke Dope revisited)

April 22, 2009

A couple days ago, we got some great feedback about our story refuting press reports about scooter emissions, notably Cecil Adams’ syndicatedThe Straight Dope column“Give a Scooter, Pollute Her.” The way Cecil framed the question left us doubting his conclusions, but we admitted there was something to his findings, and wondered about specific emissions figures.

Well, 2SB reader “JSH” tracked down some real numbers, and his comment was so thorough and insightful, we’ll just reprint the whole thing here:

Cecil’s story is quite accurate. As he said, it really depends what your goal is. If you are interested in reducing CO2, energy security, and global warming than scooters are the clear choice. If you are concerned about smog forming emissions regulated by the CARB and the EPA then scooters, even 4-strokes, are gross polluters compared to even SUV’s.

My only issue with Cecil’s story is that he compares emission standards, (the amount of pollution a vehicle is allowed to emit) instead of actual measure emission. Data for actual emission is easily available, all one needs to do is go to CARB’s website and look at the certification data. Here you will find the actual emissions data submitted by manufacturers to CARB in order to certify that the vehicle meets emission regulations. This data is collected by running the vehicle through a uniform test and measuring the emissions.

Some Scooter data:

Vehicle HC CO NOx Total
Aprilia Scarabeo 100 0.200 1.000 ? 1.200
Vespa LX 150 0.100 5.000 ? 5.100
SYM HD 125 0.900 1.000 ? 1.900
Genuine Buddy 150 0.400 7.000 ? 7.400
Genuine Rattler 110 0.900 7.000 ? 7.900
SYM HD 200 0.700 4.000 ? 4.700
CARB Regulation 1.000 12.000 ? 13.000

(Note: All numbers are grams per kilometer, scooters are not tested for NOx)

As you can see actual, scooter emission vary wildly but all are much lower than what CARB allows. One can’t really stereotype 2-stroke vs 4-stroke either. While the Rattler 110 is a 2-stroke and is the most polluting on my list it is only 7% worse that the 4-stroke Buddy.

Car and SUV data:

Vehicle HC CO NOx Total
2010 Toyota Prius 0.031 0.025 0.002 0.058
2009 Suburban 6.0L 4×4 0.026 0.559 0.012 0.597
CARB Regulation 0.056 2.600 0.043 2.699

(Note: All numbers in grams / kilometer (converted from grams / mile)

Again, vehicles vary widely but even the worst cars and SUVs are well below the emission standard. However, even the best scooter emits 20x more pollution than a Prius and 2x more than a 4×4 Suburban.

So again, it depends on what one is more concerned about. If one is more concerned about the air quality of their city than any car is better than a scooter. If one is more concerned about reducing the consumption of gasoline and other natural resources than a scooter is the better choice.

Well done, JSH, if your research and math is correct, we’re convinced, and very disappointed (Our apologies to Cecil Adams, too).

It was always hard to believe scooter manufacturers’ vague ecological hype, but on the other hand, it seemed impossible that modern 4-stroke scooters could be bigger polluters than cars. Even so, they have other benefits, but it’s hard to see past these numbers comparing actual emissions per kilometer.

As far as we’re concerned, these numbers put a pretty serious dent in any argument that scooters are “green” or environmentally-friendly, and lower gas prices temporarily put the fuel economy arguments to rest (which are also overstated in most cases), maybe now we can all get back to riding scooters because they’re fun and practical.


6 Responses to “Happy Earth Day! (2-Stroke Dope revisited)”

  1. BrookeNo Gravatar on April 22nd, 2009 10:07pm

    They do pollute less. It just depends on what you consider pollution. More fuel efficient vehicles pollute less in the way that saves polar bears, keeps coastal cities dry and Detroit has paid good money to keep off the Federal regulation hit list. CO2 is the primary pollutant that’s behind global warming. Notice it on those test charts? Nope. Why? It’d be too hard to sell F250s, Tundras and Escalades. Motorcycles have been kept to a lower standard in terms of pollutants that make smog and deteriorate local air conditions. That’s a shame. Car makers have made some nice modern engines that are so choked down that they produce very little of these compounds at the tailpipe. But in exchange we get giant motors to pull heavy “safe” (for you but not for the poor bastard you hit) bodies that get worse fuel efficiency on average than a car did 20 years ago and thus produce MORE CO2. Earth thanks you for using less gas. But the prick with emphysema in West Hollywood that keeps calling my house to sell me an extended warranty on a car I don’t own may curse you. But his troubles are exacerbated by the tug boats in the harbor burning used crank case oil from those clean 4 stroke engines that don’t belch out any particulate matter so if you are driving a Rattler 110 I guess it may not be all your fault.

  2. Those Darn McCabesNo Gravatar on April 22nd, 2009 10:23pm

    Pretty damn interesting. Someone should keep going with that chart. I’d love to see have the Bajaj and Stella fit in there. Also fuel injected scooters like the GTS250.

    Might not hurt to see some standard-ish motorcycles in the mix too to see how they compare.

    I’m confused how a Prius can have more HC (hydrocarbons) than a Suburban.

  3. chandlermanNo Gravatar on April 23rd, 2009 6:37am

    There’s another factor that gets consistently overlooked here, which is the amount of oil consumed in the manufacturing of a car or light truck. I can’t find the source with a quick google, but I seem to recall that something like 50 barrels of oil are consumed by power generation, plastics manufacture, shipping/supply chain, etc. during the course of manufacturing a vehicle, so that’s a huge environmental impact that’s getting ignored in the course of these discussions.

  4. Columbus JoshNo Gravatar on April 23rd, 2009 9:13am

    I did some thinking & number crunching on this awhile ago. I’m not sure how I feel about it any more, other than environmental issues being murky and overlapping:

  5. illnoiseNo Gravatar on April 23rd, 2009 7:54pm

    chandler, I doubt scooter manufacturing, especially in Taiwan, India, and China, is much greener than car production, and scooters are far more disposable, so I would guess that the actual manufacturing would work out to (at least) a similar amount of environmental impact per mile over the life of the vehicle. Overland and overseas shipping would certainly add to that, too, though that would presumably be a factor for cars, too.

    Josh, I linked to your story a while back, that’s a good addendum about CO2, if you could find the figures for all the vehicles that JSH listed, I’d love to add them to the chart. They do give the scooters a bit of a leg up, so that’s good. I agree, there are just so many different metrics, and so many ways to process the info that you can make any argument you want, but I really see these emissions numbers as a big blow to the pro-ecological scooter argument, especially because they’re so counterintuitive.

    The truth is, the scooter numbers are surely loads better than they used to be, it’s the fact that cars have been regulated beyond recognition.When you think about it, the story here is that maybe cars and SUVs that we think of as terrible polluters are actually pretty darn “green,” all things considered, and 2-wheelers just haven’t caught up with that level of regulation and technology yet.

  6. BrookeNo Gravatar on April 23rd, 2009 8:36pm

    I guess cars are more green if you don’t mind killing baby polar bears and the end of civilization as we know it while being able to have a few less air quality warning days per year.

    Worrying about carbon monoxide other unburned HC and NOx compounds instead of CO2 is like cutting someones arm off and being concerned about dehydration from the tears.

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