Hacker News Reader

Comment by Enginerrrd | Hacker News Reader

So, I get the frustration with bureaucracy. I'm an environmental engineer and I deal with analogies to this a lot. But to be honest, this seems like a non-issue to me either way. Like, sure, lead is bad, but one should take into account mass and concentrations before reaching for the ban hammer.

There are so few aircraft running leaded gas I can't imagine that environmental lead concentrations, could ever be at the right order of magnitude to be a problem for anyone(except probably AT airfields near fueling stations and maintenance areas). These aren't typically areas where children get exposed.

View on HN

Two papers for your reading:

* March 2022 - https://www.pnas.org/doi/full/10.1073/pnas.2118631119 - "Half of US population exposed to adverse lead levels in early childhood"

* October 2011 - https://ehp.niehs.nih.gov/doi/10.1289/ehp.1003231 A Geospatial Analysis of the Effects of Aviation Gasoline on Childhood Blood Lead Levels

The two papers (plus others) taken together suggest that the impact is measurable (paper 2), perhaps to the tune of one or two IQ points on average per person exposed (me drawing a line from paper 1).

Granted, the latter point is my extrapolation, but there's enough of a foundation now for policy decisions to be made in advance of explicit research connecting these dots.

On the first paper, roughly half the US population is >40yo, so this could well be talking about things that stopped being a problem in the 80's.

Yes, I haven't read that paper but the abstract even notes that the effect is "disproportionately endured by those born between 1951 and 1980".

The largest result in the avgas paper, for children living within 500m of an airport, put their lead levels at 0.043 micrograms/dl higher than the general population.

From this paper[1], "An increase in blood lead from 10 to 20 micrograms/dl was associated with a decrease of 2.6 IQ points". So while there is an impact on lead levels, it is not nearly large enough to lead to the loss of 1-2 IQ points.

I'm not saying we shouldn't get rid of leaded avgas, but it accounts for about 0.1% of gasoline used in the US so the impact will be much smaller than banning leaded fuel for cars was.

[1] https://pubmed.ncbi.nlm.nih.gov/8162884/

The article isn't directly about banning leaded fuel. It's about expanding approval of unleaded fuel.

You're right that from a environmental/health standpoint, it's not a giant issue. Lead emissions from general aviation are highly localized, and generally within air quality limits - with peaking areas limited to within airport limits themselves (https://www.epa.gov/regulations-emissions-vehicles-and-engin...).

But this rant is more about bureaucracy cockups. The FAA is launching another lead-free fuel initiative while sitting on approvals for an existing lead-free fuel. That's a waste of money, and it's not a sign of the competence/lack of corruption that we should expect from the FAA.

I think you're greatly underestimating the number of GA / Piston aircraft flying.

At my school, we have ~10 aircraft flying every day, 8-12 hours a day depending on the weather. Most of these flights happen over prime, in production farmland, or on the edges of the nearby town which has 8 schools at a minimum.

Now we're one of probably 5 aviation schools within a 50 mile radius, all of whom are operating at similar or greater profiles.

I'm sure the individual impact is small, but for every jumbo jet there's something like 3-5 piston aircraft in operation.

There are 220,000 GA planes in the US. The number of jetliners isn't clear, but it's something like 45k flights in the US a day (some of those are doubled up).

https://www.faa.gov/air_traffic/by_the_numbers/

But the key number is there 25,506,000 GENERAL AVIATION FLIGHT HOURS PER YEAR, which is almost exactly the amount of 100LL used a year (technically some GA flights are jet).

These GA statistics seem to include Aerial Work, so it includes a considerable number of turbine powered aircraft (most helicopters for instance.)

This Excel(!) document breaks GA hours down between types of aircraft: https://www.faa.gov/data_research/aviation_data_statistics/g...

From that document, here are the estimated total hours flown by type of general aviation aircraft:

Fixed wing piston: 12.9 million

Fixed wing turbine (turboprop + turbojet): 5.6 million

Helicopter (turbine): 1.8 million

Helicopter (pison): 0.6 million

Aside, if you compare Chart4 and Chart5 in that document, you can see that although piston aircraft are far more numerous, on average they spend a lot more time on the ground than turbine powered aircraft.

The problem is the standard is that lead in any concentration is bad. So folks swarm pink elephant issues like this because they affect a small group of people and are cheap.

If you want to be angry about government inaction on lead, the “hear no evil, see no evil” respect to lead paint and soil contamination is the thing.

Just for one example, Seattle has a lake right in the middle of town in a bowl with tens of thousands of people working and living right around it, and that lake is used as a seaplane airfield with aircraft landing and taking off every few minutes throughout the day.

A lot of small airports are smack in the middle of residential or other populated areas.

Reply on news.ycombinator.com