Lead is dangerous to human health in water, soil and air. Lead pollution in the air is regulated at industrial facilities and in communities under the Clean Air Act. Many studies have shown that children exposed to lead can develop learning disabilities and behavior problems, and damage to the brain and nervous system. A new study shows a relationship between lead pollution in air and infant deaths. The Allegheny Front’s Kara Holsopple spoke with Karen Clay, professor of economics and public policy at Carnegie Mellon University’s Heinz College, who led the study.
LISTEN to the interview
Kara Holsopple: What are the two main findings of the paper?
Karen Clay: First of all, you might think that these studies have been done, but it turns out that they haven’t. We show causal evidence that higher air-lead concentration causes higher infant mortality. This is true both for the first month of life, right after infants are born, but also in the first year, suggesting that they’re getting exposed both through their mothers when they’re pregnant, but also babies are born and are experiencing lead directly and in some cases dying from it.
Kara Holsopple: And then there’s also a relationship between Sudden Infant Death Syndrome and lead?
Karen Clay: Our second main finding is that the higher lead concentration increases deaths from a variety of causes: low birth weight, Sudden Unexplained Infant Death(SUID), and respiratory and nervous system causes.
We’re particularly excited about this Sudden Unexplained Infant Death. It used to be called SIDS and now includes some additional things. But, the earlier medical literature from when SIDS is originally identified speculated that there might be some relationship between lead and SIDS, at least for some subset of the cases. So we were really excited to see when we went to the cause of death data that there seemed to be some evidence to support those early speculations.
Kara Holsopple: How many infant deaths have or could be prevented from lowering lead air pollution?
Karen Clay: We do two calculations. We look at fugitive lead emissions, which are sort of a subset of the emissions from industrial sources: four to 59 infant deaths. But if you look at those numbers and then expand it to think about the air lead from all industrial sources, it’s about 240 infant deaths per year. The one thing I would say is that there’s other sources, particularly aviation gasoline, that are significant for air lead. And so the 240 is really just for industrial sources, not for all lead sources. We don’t have quite what we would need to try and estimate the full set, but certainly it’s probably two or three times what our estimates are.
Kara Holsopple: Say a little bit about where the data used in the study comes from.
Karen Clay: We use two different data sources. One is something that maybe people would be familiar with. Many people are aware that EPA has monitors that monitor things like particulate air pollution. Some of those monitors also monitor air-lead pollution as well. We use those EPA monitors. But the other thing that we use is data from the U.S. Toxic Release Inventory. This is where industrial firms that have more than just a little bit of emissions basically have to record a whole range of chemicals that they emit. One of the chemicals that they report is lead. They report lead in air and water and land. So it’s a very detailed data set. That data set starts in 1988 and was the result of people becoming very concerned about these issues, among other things, motivated by the Bhopal explosion and environmental catastrophe, and so led Congress to pass legislation for us to keep better track of the kinds of things that were being emitted.
“In a different review paper, we actually encourage testing of all mothers, particularly mothers who live in areas where there’s likely to be reasonably high levels of lead exposure and testing of infants,” said Karen Clay, who led the study.
Kara Holsopple: When you say fugitive lead emissions, can you just say a little bit more about what those are and how they’re different from other lead emissions?
Karen Clay: Basically, there are two kinds of emissions. There are what are called stack emissions. Those are things that literally come out of what you would think of as smoke stacks or vents. And then there are fugitive emissions. Fugitive emissions are things that don’t get captured – so if something spills or if there’s an open door. A lot of the fugitive emissions are also from debris from crushing rocks or crushing metals and various things like that that end up on the ground and then blow around.
We basically use fugitive emissions because it turns out that fugitive emissions are something that people aren’t really aware of. So sometimes if people are aware of pollution, they’ll stay inside. Really what they would be aware of would be the stack emissions – they’d look up and see that something was coming out of a smokestack or they would smell that there was something being produced. The fugitive emissions are much harder to detect and therefore much harder to avoid.
Kara Holsopple: And so you looked at these two types of data, and then you looked at wind speed?
Karen Clay: Yes. And the reason is because these fugitive emissions are typically happening at ground level. And so if there’s really no wind, then they’re just going to settle back on the ground kind of where they are. But if there’s significant wind, then what happens is they blow further away, right. And so they’ll blow a mile or two miles, and impact population in those adjacent areas. And so wind speed turns out to be important in terms of thinking about how many people would be exposed and then what the resulting effects would be.
Kara Holsopple: In the U.S., what are the main sources of lead pollution in air? When you say industry, what types of industry are we talking about?
Karen Clay: So a lot of it is metals processing of different kinds. Some of it is lead processing, but some of it is if you’re a pipe manufacturer or if you’re making various metal objects. Depending on what they are, sometimes they’re using copper, they’re using zinc, and sometimes those things have lead in them as well.
But industrial lead is the second biggest. They’re about 350,000 pounds emitted in 2022. And the first biggest is aviation lead, which is about 500,000 pounds. So lots and lots of emissions, right? Because even just a tiny fraction of a pound is dangerous for people and particularly dangerous for children. The fact that we’re still emitting these really large amounts, they’re not as large as they were back in the days when we had leaded gasoline, but they still remain significant.
- Pennsylvania to receive $43 million in federal funds to remove lead paint from homes
- Report calls for tougher lead testing standards for Pa. school districts
Kara Holsopple: How can this study be used to better understand exposures to lead and to mitigate them?
Karen Clay: In a different review paper, we actually encourage testing of all mothers, particularly mothers who live in areas where there’s likely to be reasonably high levels of lead exposure and testing of infants. And the reason to do that is because we often don’t test kids until age two. And by then, a lot of important development has already happened. And if we know that the child was exposed, either because the mother has high blood lead levels or the infant has high blood levels, then we can start treating and mitigating much sooner. We can try and identify, are they getting air exposure? Are they getting water exposure? What can we then do to mitigate that exposure?
Kara Holsopple: As you mentioned, data for the study came from the Toxic Release Inventory and EPA monitors. The administrator of the EPA recently announced his intention to cut staffing at the agency. How important is accurate data from federal and other agencies when you’re doing health studies like these?
Karen Clay: It’s critical. The EPA has been incredibly important in providing data which has helped identify various kinds of exposures to various kinds of pollution and toxins. These data are foundational. Similarly, federal data on things like infant health and infant mortality is really foundational for research purposes. And so we really hope that data collection will continue.
***
Karen Clay is a professor of economics and public policy at Carnegie Mellon’s Heinz College. She led the study, “The Hidden Toll of Airborne Lead: Infant Mortality Impacts of Industrial Lead Pollution,” with researchers at Boston College and Hunan University. The study is a National Bureau of Economic Research Working Paper.
