Small piston-engine airplanes often use leaded fuel. And children who live near where they fly can harbor concerning levels of lead in their blood.
That’s the conclusion of a just-released study led by economics professor Sammy Zahran of Colorado State University that used a California Department of Public Health blood sample database from more than 14,000 young children living near Reid-Hillview Airport in Santa Clara to see whether their proximity to the airport impacted lead levels in their blood. The findings were published in the journal PNAS Nexus.
Lead used to be a common additive in vehicle fuel, paint and other products, but has been largely phased out because of the dangers posed by exposure to lead — particularly for children 5 and younger. Lead levels above a certain level have been shown to harm young brains especially.
In the United States, small aircraft still use leaded fuel and NewScientist reports that “today, these aircraft are responsible for two-thirds of lead pollution in the U.S.”
In August 2021, the Santa Clara County Board of Supervisors announced that leaded aviation fuels would no longer be sold at Reid-Hillview Airport and San Martin Airport, based on findings of a study it commissioned.
But the new study’s findings, while conducted using data from the small airport in California, apply to other airports where small piston-engine aircraft come and go.
What lead does to young brains
The Centers for Disease Control and Prevention said that lead exposure in young children “can seriously harm a child’s health and cause well-documented adverse effects.” Its list of harms include:
- Brain and nervous system damage.
- Developmental and growth delays.
- Learning and behavior challenges.
- Hearing and speech deficits.
As a result, children can have lower IQ, decreased focus and academic challenges, the CDC said. The harm can be long-term.
“Across an ensemble of tests, we find consistent evidence that the blood lead levels of children residing near the airport are pushed upward by the deposition of leaded aviation gasoline. This indicates we should support policy efforts to limit aviation lead emissions to safeguard the welfare of at-risk children,” Zahran said in a written statement.
The airport study
The study said that about 4 million Americans live within a half mile of an airport where small piston-engine aircraft fly. And nationwide, about 600 elementary schools are close to such airports, as well.
Studying children living within 1.5 miles of the airport, the researchers found that the closer the children lived, the more apt they were to have a blood lead level that exceeded California’s safety threshold of 4.5 micrograms per deciliter.
The CDC says anything above 3 micrograms per deciliter is concerning, while UK officials are concerned about 5 micrograms per deciliter.
“Lead levels in children who lived downwind of the airport were more than twice as likely as those living elsewhere to be above the threshold of concern,” per New Scientist.
The study said the young children within a half mile of the airport had the highest blood lead levels. Per U.S. News & World Report, “In this study, the probability that a blood sample would exceed the state’s safety threshold was 21.4% lower for children living a mile or more from the airport than it was for children living within a half mile of the airport.”
Those downwind of the airport were more than twice as likely to have a blood lead level about the threshold for concern, the study said.
And levels went up when the small aircraft traffic was heaviest. Adding backing to the notion that the lead levels were related to the proximity to the small aircraft, the researchers said that when flights were more infrequent due to the pandemic, levels of lead in the blood samples was lower, as well.
The researchers were also able to show that the existence of an old San Jose Raceway southwest of the airfield, where unleaded fuel was used for a long time, did not provide an alternative explanation for their findings, per the study.