A study of children living near a small airport in California finds that those within 1.5 kilometres have concerning levels of the poisonous metal lead in their blood
10 January 2023
Children living near airports for small aircraft that use leaded fuel may have concerning levels of lead in their blood.
Lead used to be added to vehicle fuel to improve engine performance. By the mid-20th century, it was realised that lead in the environment has harmful effects on human health, including killing brain cells, with young children particularly vulnerable.
As a result, lead was phased out of fuel for most vehicles and removed from household substances, such as paint.
But in most countries, including the UK and US, small aircraft were allowed to continue using leaded fuel. Today, these aircraft are responsible for two-thirds of lead pollution in the US.
To find out if this presents a risk to children living near airports, Sammy Zahran at Colorado State University and his colleagues looked at a database of more than 14,000 blood samples from children under the age of six living within 2.4 kilometres of Reid-Hillview Airport in Santa Clara County, California, between 2011 and 2020. The samples had been taken by the California Department of Public Health.
Zahran and his colleagues found that the closer children lived to the airport, the more likely they were to have a blood lead level of higher than 4.5 micrograms per decilitre, which California has defined as a threshold of concern.
This is similar to the threshold recommended by the US Centers for Disease Control and Prevention, of 3.0 micrograms per decilitre, and to that set by UK public health authorities, of 5.0 micrograms per decilitre.
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.
The county of Santa Clara, which owns the airport, hasn’t responded to a request for comment.
The blood lead levels recorded in the period between February and July 2020, when fewer flights were made because of covid-19 restrictions, were lower. This supports the premise that local children’s high lead levels are a direct result of plane emissions, says Zahran. “You can think of this as a natural experiment,” he says.
While the relationship between distance from the airport and lead levels is complex, he says, “children residing within 0.5 to 1.5 kilometres present with elevated risk”.
The finding is likely to add weight to calls for small aircraft to switch to alternative unleaded fuels, although these aren’t yet widely available.
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