In 2008 there were 167,000 small planes. The discounted present cost of future lost productivity due to the lead in their gas in any given year is $1.63 billion. That's about $9760 of lost productivity per year you choose to fly that plane.
Some models put the cost of lost productivity due to lowered IQ much higher, for about $11.3 billion. That's about $67,700 per plane per year of damage caused to others (mostly poor and often minorities).
Do you think this qualifies as "blood on his hands"?
People will differ in their opinions on that. Certainly if he was breaking into poor people's houses and trashing them, everyone will condemn him. But he clearly had no intention to do harm, and probably had no idea of the full extent of the harm that he has been doing. There is also room for people to argue with the assumptions in the scientific model.
But the range of defensible opinions ABSOLUTELY includes his having the blood of poor people on his hands.
There are other issues. For example, they say that for children, the main exposure is through ingestion. How exactly are they ingesting the lead particulates? Unclear. They do say it's difficult to determine and they try to account for that (they spend several paragraphs discussing this).
They also say that the contributions from planes in flight (as opposed to takeoff/landing) may be indistinguishable from background concentrations or lower than monitor resolution detection limits(!!!). So more modelling is used.
> Research suggests that forest fires and lead re-emissions from soil are increasingly important sources of lead to the atmosphere.58,59 These sources, like aviation, were an insignificant source of airborne lead during the peak of leaded gasoline, but now may be a principal source of emissions in certain regions. Further, leaded paint and paint dust is expected to be the largest contributor to childhood lead exposure, with exposure risk being spatially and demographically heterogeneous.
Lead paint is STILL the largest contributor.
We need to get rid of lead as much as we can, true. But to go so far as say "blood of poor people" it's a step too much. Specially based on a single paper full of "models" (aka educated guesses).
But IF the model is correct, the impacts are severe. Doubly so if the upper range is correct. And so we have the ethical question of how we should progress in the event of uncertainty.
On this question some hold the perfectly defensible position is that, when faced with such uncertainty, we should assume the worst until we have more information. That a person who is aware of the potential for harm and fails to act merely because they are not certain of it deserves the full blame for the harm that they are aware might have happened.
For someone who takes this position, "blood of poor people" is definitely not a step too far.
Note: I am very carefully not saying that this is a correct or universally accepted position. I'm merely saying that this is a position that some hold for reasonable reasons, and can be defended.
Number of cars on the road in US: 284,000,000 [1]
[0] https://www.faa.gov/newsroom/general-aviation-safety
[1] https://www.statista.com/statistics/859950/vehicles-in-opera...
The CO2 impact of GA doesn't even rise to the level of "in the noise" compared to that of cars. This doesn't make it good, but it does make the problem low priority.