Study Finds Elevated Blood Lead Levels in Children Living Near Airports

Miki Barnes
May 28, 2020

"The Effect of Leaded Aviation Gasoline on Blood Lead in Children" by Sammy Zahran (Colorado State University), Terrence Iverson (Colorado State University), Shawn P. McElmurry (Wayne State University) and Stephen Weiler (Colorado State University) was published on-line on 4/11/2017. The study, which "links time and spatially referenced blood lead level data from over a million children to 448 nearby airports in Michigan," provides compelling evidence of endangerment resulting from the continued use of leaded aviation fuel, also known as avgas, by piston engine aircraft.[1]

As noted in the report, "...for the approximately 16 million people - and 3 million children - who live within a kilometer of airport facilities that service piston-engine aircraft, the continuing flow of lead into the environment remains a potentially serious source of exposure risk."[2]

Piston engine aircraft comprise "about 70% of the U.S. air fleet."[3] These types of helicopters and fixed wing aircraft, often used by flight training companies such as Hillsboro Aero Academy and ATP as well as private pilots, are responsible for close to two-thirds of airborne lead emissions in the U.S. Commercial jets do not use leaded fuel.

Among the 448 airports considered in this report, "the average monthly number of piston engine aircraft operations ranged from 7 to 1,099."[4] By contrast, the Hillsboro Airport (HIO), which ranks 8th in the nation among more than 21,000 airports in lead emissions, logged an average of 17,259 operations on a monthly basis in 2017. According to the FAA terminal area forecast, the total number of HIO operations that year was 205,908.

Health, Developmental, and Social Impacts of Lead

The researchers identify lead as a neurotoxin, "with developmentally harmful effects in children," and further explains,

"Children exposed to lead have diminished life chances. Studies link lead exposure to adverse mental and behavioral outcomes, such as IQ loss, poor academic achievement, attention-deficit disorders, delinquency, and violence and to irreversible health problems such as hypertensive disorders, damage to renal and cardiovascular systems, and tooth decay."[5]

The report also states,

"The consequences of lead exposure in childhood are lasting. Neural-imaging studies find that adults exposed to lead as children have reduced gray matter in regions of the brain known to govern executive judgment, impulsivity and mood regulation...Economists have convincingly linked these intellectual and socio-emotional traits of judgment and impulsivity to long-term life outcomes...persons exposed to lead in early life experience 'an unfolding series of adverse behavioral outcomes: behavior problems as a child, pregnancy and aggression as a teen, and criminal behavior as a young adult.'"[6]

Elevated Blood Lead Levels in Children Living Near Airports

The report provided consistent and clear evidence that avgas is significantly linked to elevated BLL [Blood Lead Levels] in children living near airports.

The findings revealed that blood lead levels in children

• Increased in proximity to airports – The study found that children residing with 1 kilometer of some airports were "25% to 45% more likely to exceed present and past thresholds of concern [set by the CDC] than children at ≥4 km from an airport."[7]
• Declined in the months after 9/11 among children living near airports – The researchers found evidence of a significant reduction in blood lead levels in the months following the terrorist attack. The researchers noted that avgas sales were measurably lower in September, October and November of 2001.[8]
• Increased in the flow of piston-engine aircraft traffic
• Increased significantly in the percentage of downwind days. The report found that the direction of the prevailing winds has a significant impact on where lead is emitted.

Environmental Justice Implications

In addition, the authors identified social justice implications among those more likely to live in proximity to airports. "Studies show that children of low socioeconomic status are at greater risk of presenting with elevated BLLs."[9]

• "In Michigan, populations of lower socioeconomic status are more likely to reside near airports. Compared to more distant neighborhoods (9-10 km), neighborhoods within 2 km of an airport have significantly higher percentage of households receiving public assistance..."[10]
• Those living in close proximity to airports had "lower levels of educational attainment among adults."[11]

Social and Economic Costs

The report also looked at the social cost of avgas exposure by linking blood lead levels to IQ loss and IQ loss to future earnings. They found that reducing piston-engine aircraft traffic in Michigan from the 50th percentile (407 monthly operations) to the 10th percentile (133 monthly operations) would generate a social benefit, measured in terms of the net present value of future earnings, of about $120 million.[12]

"According to the analysis, a hypothetical reduction in PEA [Piston-Engine Aircraft] traffic from the 50th to the 10th percentile would generate a 5-year cohort benefit of $126 million for Michigan and $4.9 billion nationwide."[13]

The authors pointed out that this measurement of economic costs due to leaded aviation fuel focused only on IQ loss, and did not factor in other negative impacts such as "growth stunting, seizures, and lasting damage to various body systems" or the economic costs associated with "lead-linked crime, including victim costs, criminal justice processing, incarceration, as well as lost earning to victims and perpetrators of crime."[14]

Hillsboro Airport

To put this into perspective, the Hillsboro Airport (HIO) often logs 600 operations or more per day. This is far more than many Michigan airports log in an entire month. Many HIO-based student pilots engage in touch-and-go training patterns wherein they repeatedly circle below 2000 ft. within four to five miles of the airport. They also circle and loop repeatedly over rural communities, prime farmland, recreational areas and waterways, all the while depositing lead into the air and the soil. The noise, lead emissions and other pollutants released by these pilots pose a serious health and environmental threat to this community.

For additional information on this topic, see the 2011 Environmental Health Perspectives article entitled A Geospatial Analysis of the Effects of Aviation Gasoline on Childhood Blood Lead Levels by Marie Lynn Miranda, Rebecca Anthopolos, and Douglas Hastings. This study also found elevated blood lead levels in children living in proximity to airports where leaded aviation fuel is used.

Sources

[1] Zahran, Sammy, Iverson, Terrence, McElmurry, and Weiler, Stephan. The Effect of Leaded Aviation Gasoline on Blood Lead in Children. Journal of the Association of Environmental and Resource Economists, JAERE. (04/11/2017). Pg. 575. Last accessed on-line on 5/27//2020.

[2] Ibid. Pg. 579.

[3] Ibid.

[4] Ibid. Pg. 577.

[5] Ibid. Pg. 575-576.

[6] Ibid. 605.

[7] Ibid.

[8] Ibid. Pg. 584.

[9] Ibid. 582.

[10] Ibid. Pg. 577

[11] Ibid.

[12] Ibid. Pg. 578.

[13] Ibid. Pg. 605.

[14] Ibid. Pg. 578. Footnote 6.