4 ms·

Don't involve "belief", just run the numbers and show your work, unlike the Twitter guy! :-)

fauigerzigerk 11y ago
It's probably a terrible idea for me to do this as I am completely unqualified, I don't have all the required numbers, and I don't have much time to double check or even think this through properly, but it seems that on the back of an envolpe, everything goes! The average diesel passenger car emitted about 8kg of NOx in 2008 and a third less in 2015 according to [1] and [2], so on average that's 6.6kg per car per year. If VW emitted 20 times that much since 2009, as alleged, that's 6.6 * 20 * 6 years = 792kg. An average diesel engine would have emitted 40kg, so that's 752kg extra for VW. Multiply by 500,000 cars = 376,000 tons of extra emissions. [2] claims that cutting emissions by 187,000 tons saves 4000 lives. Hence, 376,000 tons should cause about 8000 deaths. That's assuming NOx levels and deaths have a linear relationship, which is highly doubtful. So it appears that my feeling/belief that 500,000 cars could not have caused 100,000 deaths is correct. But if all 11 million VW cars of that type worldwide have that same "defect", then of course the number of premature deaths rises to 176,000. All of this is most likely complete bullshit, but you are right, it makes sense to at least try to run some numbers ;-) [1] http://www3.epa.gov/otaq/consumer/420f08024.pdf http://www3.epa.gov/otaq/consumer/420f08024.pdf [2] http://www.arb.ca.gov/msprog/ordiesel/documents/OFRDDIESELhealthFS.pdf http://www.arb.ca.gov/msprog/ordiesel/documents/OFRDDIESELhe... [Edit] I already found a mistake in my estimate. The NOx numbers in [1] don't seem to be for diesel or not only for diesel engines. But other sources give similar averages for diesel engines (after the catalytic converter does its job of course)
- jddaigle 11y ago
  The cars also used less fuel and emitted less CO2 in real-world conditions than they did in the tests--what does that do to the calculations?
  - ars 11y ago
    > less CO2 .... what does that do to the calculations? Nothing at all. First CO2 does not cause any deaths, unlike pollution. Second the amount of CO2 is very small compared to global emissions, so it's quite irrelevant.
- scott_karana 11y ago
  You rock. This is why I come to Hacker News. :-)

It's probably a terrible idea for me to do this as I am completely unqualified, I don't have all the required numbers, and I don't have much time to double check or even think this through properly, but it seems that on the back of an envolpe, everything goes! The average diesel passenger car emitted about 8kg of NOx in 2008 and a third less in 2015 according to [1] and [2], so on average that's 6.6kg per car per year. If VW emitted 20 times that much since 2009, as alleged, that's 6.6 * 20 * 6 years = 792kg. An average diesel engine would have emitted 40kg, so that's 752kg extra for VW. Multiply by 500,000 cars = 376,000 tons of extra emissions. [2] claims that cutting emissions by 187,000 tons saves 4000 lives. Hence, 376,000 tons should cause about 8000 deaths. That's assuming NOx levels and deaths have a linear relationship, which is highly doubtful. So it appears that my feeling/belief that 500,000 cars could not have caused 100,000 deaths is correct. But if all 11 million VW cars of that type worldwide have that same "defect", then of course the number of premature deaths rises to 176,000. All of this is most likely complete bullshit, but you are right, it makes sense to at least try to run some numbers ;-) [1] http://www3.epa.gov/otaq/consumer/420f08024.pdf http://www3.epa.gov/otaq/consumer/420f08024.pdf [2] http://www.arb.ca.gov/msprog/ordiesel/documents/OFRDDIESELhealthFS.pdf http://www.arb.ca.gov/msprog/ordiesel/documents/OFRDDIESELhe... [Edit] I already found a mistake in my estimate. The NOx numbers in [1] don't seem to be for diesel or not only for diesel engines. But other sources give similar averages for diesel engines (after the catalytic converter does its job of course)

jddaigle 11y ago
The cars also used less fuel and emitted less CO2 in real-world conditions than they did in the tests--what does that do to the calculations?
- ars 11y ago
  > less CO2 .... what does that do to the calculations? Nothing at all. First CO2 does not cause any deaths, unlike pollution. Second the amount of CO2 is very small compared to global emissions, so it's quite irrelevant.
scott_karana 11y ago
You rock. This is why I come to Hacker News. :-)