NASCAR, leaded gas, and the true cost of dirty air
New research suggests the social cost of a single gram of lead in fuel is more than $1,100. The real cost of dirty air is likely far more than the cost to clean it.
What’s the real cost of dirty air?
Race cars and leaded gas can help provide an answer.
There’s some interesting new research that involves race cars, a clever natural experiment, and the health and economic costs of environmental lead. If you want to just skip to that, scroll away! If you’d like to learn more about lead as a material and why it’s so harmful to humans, then just keep reading.
As always, if you like what you are reading please share this piece with friends, family, lead-skeptics, European monarchs, minor celebrities, or anyone else who comes to mind.
Lead, as a material, is versatile and useful.
To understand how lead became so pervasive in society, you need first to understand its properties. Lead is in many ways an amazingly unique material, and human societies have been using lead in the built environment for several thousand years. Unlike many other metals, it’s soft and easy to smelt and work with at only modest temperatures, and as such it was accessible to cultures with very limited technology.
Its first use goes back to 6,400 BCE, to a neolithic settlement in Turkey. Lead was among the first metals used by the Chinese, the Egyptians, the Babylonians, the Assyrians, the Greeks, and the Romans. Though it was not suitable to use in most melee or early projectile weaponry, it does not corrode or rust, so it endures despite exposure to the weather.
Lead’s combination of malleability and durability has made it extremely useful to virtually every known society.
The Romans famously made wine in lead-lined kettles, because lead imparted a sweetness to the wine that other metals did not. They also used lead for piping water, because lead pipes held up over time. Lead’s atomic symbol, Pb, is from the latin plumbum, and the root of the English word plumbing.
Lead was used for coins throughout the world, for cheap pots, pans, condiments, and kitchen vessels, and even, as the EPA points out, for chastity belts. Later lead was used to make stained glass windows, as solder, and for moveable type for printing presses. We take for granted the ability to produce durable goods from any material we like, but throughout human history, people were constantly exposed to lead because it was the best material for the job. It was lead or something far inferior or more expensive.
So people used lead. A lot of it.
But lead is unequivocally poison.
The old adage that the “dose makes the poison” isn’t true for lead. Lead is unsafe at any level. High exposures of lead lead to obvious symptoms - even the ancients noticed this - but every bit of lead in your body harms you. It causes harm less, as it turns out, from what lead does, and more from what it does not do.
The big problem with lead is that the body treats it like it’s calcium. Calcium is essential almost everywhere in your body. You need calcium, as you probably know, for strong bones and teeth (where 99% of calcium resides), but your muscles use calcium to move you, your heart uses calcium for signaling, and perhaps most importantly, calcium is critical to how your brain carries and stores information. Calcium is everywhere, and you can’t live without it. So when we say the body thinks lead is calcium, you can begin understand the problem:
Lead isn’t calcium.
Lead doesn’t do what calcium does, but the body doesn’t know it.
When lead gets into your bloodstream and central nervous system, your brain lets it in. It thinks, “hey there’s my friend calcium, come on in, I have a job for you,” but the lead just comes in and sits there.
Lead can also cross the placental barrier, so women who are pregnant can inadvertently harm their kids in utero.
The body just doesn’t recognize that lead is poison.
Rather, it assumes that lead will do the job calcium does. And because calcium is so critically involved in so many bodily processes, the consequences are both frustratingly subtle and dangerously sweeping.
The effects on developing brains is particularly bad because calcium is so critical to neural signalling.
This Conversation piece summarizes the issue well.
Lead is a dangerous toxin for people of all ages. But it is especially dangerous for young children. In young developing brains it alters brain development and changes the architecture, ultimately causing learning problems and lower IQs. In the brain lead interferes with with the release of signaling molecules called neurotransmitters, it inhibits function of a receptor (N-methyl-D-aspartate-type glutamate receptor) vital for memory and forming new neural connections, and raises the levels of a messenger molecule called protein kinase C. Taken together, these effects diminish the the number of synaptic connections during a critical early period of postnatal development.
Lead disrupts bodily functions almost everywhere, especially for the young and the frail.
There is no safe level of lead exposure for this reason, and that is what makes environmental lead so hazardous.
For this reason it was particularly unfortunate that lead ended up being so good at making early automobiles run better. Early cars suffered a lot of irregular combustion, what’s known as “engine knock.” Octane levels (e.g. 87,89, 91, etc) are a measure of your fuel’s resistance to knock, which is why higher octane fuels are used for many premium cars with performance engines - the better engines with more compression need better fuel.
100 years ago this month, a GM engineer named Thomas Midgley Jr discovered that tetraethyl lead (four small organic molecules attached to an ion of Pb) raised fuel octane when added. This was such a helpful discovery that it was a big economic opportunity for GM. As described here,
While ethyl alcohol could do the same trick, GM could patent tetraethyl lead, and formed the Ethyl corporation to market its invention around the world.
Lead was added to almost all automotive fuel in the US for 40 years, in addition to being added to paint for decades. While lead paint is a problem, it’s harder for this lead get into the bloodstream, since most people aren’t breathing aerosolized paint or eating flakes of lead paint. So it was the lead in gas that was the real problem. Once lead started being removed from gas, kids’ blood lead levels fell dramatically, almost perfectly in line with the reduction of lead.
Inhaled lead gets into blood with near terrible efficiency, and it stays in the body, primarily leaching into the bones and teeth. Because of this, we know that a lot of people alive today, especially in urban environments with more exposure to exhaust and lead pollution, suffered greatly in their youth. A Case Western Reserve University looked at teeth, for example.
Extrapolation from lead analyses of teeth from 124 residents of urban Cleveland neighborhoods show that "at the peak of leaded gasoline usage, in the 1960's and early 70's, the levels of lead in the bloodstream were likely to be toxic,"
There is compelling data that the drop in blood levels played a significant, if not primary role in the drop in violent crime. That research is summarized well by Kevin Drum here, but this is the chart that sort of makes the argument.
Thankfully lead was removed from gas, but there were a few exceptions.
The NASCAR Exception
NASCAR, the American race car sanctioning body and race operator, is exempt from the 1970 Clean Air Act, and consequently was able to operate using leaded gasoline for decades. Not until January of 2006 did NASCAR announce a move to switch away from leaded gasoline, and even then, they did not complete the transition until 2007-2008. They just couldn’t find an additive that worked as well as lead until then.
Were NASCAR vehicles just a few old cars petering about town this wouldn’t be a big deal, but a NASCAR race involves dozens of huge vehicles burning vast volumes of fuel at extremely high speeds for several hours, all in one place.
So even though races typically just once a year in a given location, there was reason for Alex Hollingsworth and his fellow researchers to think that they could detect the local health effects of the increased lead exposure.
The NASCAR Lead Natural Experiment Results:
The researchers looked at the effects of races on two things: kids’ blood lead levels and elderly mortality and given that racing isn’t always happening, they are astonishing.
Children's blood lead levels appear to be nearly 20% lower in race counties after the switch to unleaded fuel.
That is, activity at race tracks elevated average blood levels among all children in the counties where races took place, and did so in counties bordering race counties as well, though the effects were not as great. It’s very easy to see in this plot.
BLL in kids since this time has been near zero. Hollingsworth suggests that while lead from past races could be contributing, the large drop after the change suggests that it was the airborne lead from individual races driving the effect on kids.
Other research from Hollingsworth showed a large reduction in lifetime lead exposure for kids.
But the effects of lead were not limited to kids. The races were also observable in the elderly, and again, the effects were pretty dramatic.
All cause elderly mortality in race counties dropped by 91/100,000 after races dropped lead.
Again, this is all-cause mortality in people over 65 for an entire year, for races that occur just once a year.
It’s really pretty remarkable. People lived for decades near race tracks, and they had no idea that they were exposed to toxic levels of lead.
The Social Cost of Lead
The problem here is that while identified lead exposure can be treated, airborne exposure like this is not broadly recognized, and some effects on developing brains are irreversible. And of course death is a permanent outcome. Even with this in mind, the social cost in dollars is enormous.
The cost to kids is the largest component. There is no way that the below text can be improved except by emphasizing it.
We estimate that the reduction in annual lead emissions from deleading NASCAR and ARCA races yielded social benefits of $1,800 per child in counties with racetracks, and $600 per child in bordering counties through avoided IQ reductions. The benefits from avoided premature elderly mortality in racetrack and bordering counties are over $15 million per race, totaling $2.2 billion per year.
These annual benefits are more than the estimated value of all NASCAR teams combined
$1800 per year per child. The authors add:
The mortality effects alone put a lower bound on the social cost of a gram of lead in gasoline at $1,100. These magnitudes, while large, are consistent with prior observational findings on the relationship between adult mortality and lead exposure
Lead is super dense, so a gram is a tiny amount. In terms of volume, lead is more than 100x more dense than a gram of sugar, so imagine something more than 100 times smaller than a sugar cube, made out of lead, would weigh the same.
During a race, around 10 kilograms of lead are released within three hours. As a consequence,
“A single three- hour race emits…as much lead as the average airport in an entire year.”
Airports are a story for another day, but much aviation fuel still contains lead, so communities near airports, or workers at airports, likely have more exposure (e.g. any) than is healthy. And because like the NASCAR fuel, it’s being aerosolized, that lead is likely making its way into brains and affecting mortality.
Cleaning the air will yield huge benefits.
We spend almost all of our time indoors. This is kind of sad, because we evolved spending virtually all of our time outdoors, but the plus side of being an indoor species is that it is much easier to clean indoor air than outdoor air.
We should be cleaning all our indoor air.
We could, with a little effort and surprisingly little cost, clean all of our indoor air. Cleaning and ventilating filtered air would dramatically reduce respiratory infection (this study suggests good ventilation is as effective as 50% vaccination for flu), but it would also make us healthier and smarter.
The benefits of cleaner air are likely in the thousands of dollars per person per year, and the costs in common areas like classrooms, are around $10 / person / year. It is a no brainer.
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This was amazing to read! So one race has social costs of ~$10M just from the emitted lead? Pretty shocking.
I have one question about the last part. When you say we should filter indoor air, the benefits are for OTHER things like PM2.5, right? I'm guessing that aerosolized lead from combustion is too small for HEPA filters, right? But they could catch lead in other sources like dust.