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> The Guardian calculated that third graders – students aged eight or nine – who have grown up within two miles of Portland International Raceway could experien

> The Guardian calculated that third graders – students aged eight or nine – who have grown up within two miles of Portland International Raceway could experience more than a six percentage point decline in their standardized test scores. How did they calculate this? Leaded gas is only used in specialty or vintage race cars. There are less than a dozen applicable events in a year. They are claiming a larger drop in IQ than the population had when every single car was running leaded gas. I'm not defending the use of leaded gas, but being next to an airfield is probably much, much worse in the amount of lead exposure.

PaulHoule 2y ago
"Standardized test" is pretty vague. I remember reading about drops in IQ scores which are on a scale centered around 100 where anything outside 50-150 is really exceptional (many tests don't go higher than that), whereas the SAT runs from 400-1600 which is a swing about 10x higher, so maybe 6 pts on the SAT is like 0.6 on IQ. The difference between the airfield and the racetrack is that the race car could be switched to some other high octane gas or you could race some other kind of car whereas for general aviation you really don't want an engine to fail when you're in the air and the industry is both essential and moribund at the same time so you it's hard to ask people to get new planes or new engines.
- ahazred8ta 2y ago
  It's about 13 combined SAT points per IQ point. On a single SAT score, the 400-600 range corresponds to an 85-115 IQ range. On the Math+Verbal combined score, the average is 1000 and +/- 200 points is roughly +/- 15 IQ points.
elmerfud 2y ago
So this is not quite true about when leaded gasoline is used. It is generally used in track specific cars. Vintage cars have long been retrofitted to not need let it gasoline. If those vintage cars have not been retrofitted it's fine because they literally don't put enough stress on the engines to need it. But there are street legal cars that have a track mode which changes the tune on the car and bypasses the catalytic converters while in that mode. The optimized tune can require 100+ octane gas. The way this is typically achieved is by taking a 118 octane leaded gas that is sold at the race track and mixing it with a lower octane gas to get the octane rating you need for your tune. Leaded it gas is not actually required to do this. It's just what's used because it's, probably, cheaper than unleaded alternatives. Additionally with unleaded alternative fuels that have very high octanes they generally require a different tune on your car. Because even for racers you can get ethanol blended gas or even pure ethanol which has a high enough octane rating but the tune on your vehicle is different because how it burns in the engine is different. So typically changes like this don't really happen until there is legislation that pushes the conversion to happen. Which it is long past time for leaded gasoline to completely disappear in every aspect. If there is still some exceedingly limited niche then it needs to be sold as an additive which is controlled and you must show you have a need for this. Although I'm really not sure what that need would be at this point. Some small engine airplanes do still use leaded gas. I'm not sure if they still do this but as part of pre-flight checks on those small airplanes they would check the gas to make sure it is the correct gas for the plane and then just dump that out onto the ground after they validated it. There's literally no reason for piston engine aircraft to continue to use leaded gasoline either. Especially considering that aircraft are highly regulated with the number of hours that can be on an engine before it's torn down and rebuild. There is plenty of opportunity to update these to unleaded.
LorenPechtel 2y ago
Yeah, airfield. Some older planes are still allowed to use leaded gas because no alternative has been found that works with their engines. And our regulatory system is all about minimizing risk of any given activity, not in minimizing the overall risk to people.

PaulHoule 2y ago

"Standardized test" is pretty vague. I remember reading about drops in IQ scores which are on a scale centered around 100 where anything outside 50-150 is really exceptional (many tests don't go higher than that), whereas the SAT runs from 400-1600 which is a swing about 10x higher, so maybe 6 pts on the SAT is like 0.6 on IQ. The difference between the airfield and the racetrack is that the race car could be switched to some other high octane gas or you could race some other kind of car whereas for general aviation you really don't want an engine to fail when you're in the air and the industry is both essential and moribund at the same time so you it's hard to ask people to get new planes or new engines.

ahazred8ta 2y ago
It's about 13 combined SAT points per IQ point. On a single SAT score, the 400-600 range corresponds to an 85-115 IQ range. On the Math+Verbal combined score, the average is 1000 and +/- 200 points is roughly +/- 15 IQ points.

elmerfud 2y ago

So this is not quite true about when leaded gasoline is used. It is generally used in track specific cars. Vintage cars have long been retrofitted to not need let it gasoline. If those vintage cars have not been retrofitted it's fine because they literally don't put enough stress on the engines to need it. But there are street legal cars that have a track mode which changes the tune on the car and bypasses the catalytic converters while in that mode. The optimized tune can require 100+ octane gas. The way this is typically achieved is by taking a 118 octane leaded gas that is sold at the race track and mixing it with a lower octane gas to get the octane rating you need for your tune. Leaded it gas is not actually required to do this. It's just what's used because it's, probably, cheaper than unleaded alternatives. Additionally with unleaded alternative fuels that have very high octanes they generally require a different tune on your car. Because even for racers you can get ethanol blended gas or even pure ethanol which has a high enough octane rating but the tune on your vehicle is different because how it burns in the engine is different. So typically changes like this don't really happen until there is legislation that pushes the conversion to happen. Which it is long past time for leaded gasoline to completely disappear in every aspect. If there is still some exceedingly limited niche then it needs to be sold as an additive which is controlled and you must show you have a need for this. Although I'm really not sure what that need would be at this point. Some small engine airplanes do still use leaded gas. I'm not sure if they still do this but as part of pre-flight checks on those small airplanes they would check the gas to make sure it is the correct gas for the plane and then just dump that out onto the ground after they validated it. There's literally no reason for piston engine aircraft to continue to use leaded gasoline either. Especially considering that aircraft are highly regulated with the number of hours that can be on an engine before it's torn down and rebuild. There is plenty of opportunity to update these to unleaded.

LorenPechtel 2y ago

Yeah, airfield. Some older planes are still allowed to use leaded gas because no alternative has been found that works with their engines. And our regulatory system is all about minimizing risk of any given activity, not in minimizing the overall risk to people.