Technical Update: Reports on the Impact of Lead Emissions from Piston-Engine Aircraft on Air Quality Near U.S. Airports

Technical Update: Reports on the
Impact of Lead Emissions from
Piston-Engine Aircraft on Air Quality
Near U.S. Airports
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Lead Emissions from Piston-Engine Aircraft and Air Quality
EPA's modeling and monitoring data indicate that lead concentrations at and near airports are
typically well below the National Ambient Air Quality Standard for lead (lead NAAQS).2
Among the more active airports in the United States, there are a few where lead concentrations
may be above the lead NAAQS, in very close proximity to where aircraft conduct pre-flight
engine checks. For the vast majority of airports, these small areas with lead concentrations
potentially above the air standard are within the fence line of the airport and not accessible to
the public, in all but a few instances. Lead levels dissipate quickly with distance from piston-
engine aircraft exhaust. Thus, within 50 meters of the high concentration area, lead levels were
uniformly below the lead air standard.
EPA is concerned about all potential sources of lead exposure, including these low concentra-
tions in air from piston-engine aircraft, and there are actions that can and are being taken to
reduce lead from this source. These actions include making unleaded fuel available and taking
steps to mitigate the potential for elevated lead levels beyond airport property. The Federal
Aviation Administration (FAA) shares EPA's concerns about lead emissions from piston-engine
aircraft, and FAA has a program underway to identify unleaded alternatives for the fleet of
piston-engine aircraft.3 EPA recognizes the need for continued effort to further reduce lead
exposure, especially for children, due to the potential impact of multiple sources of lead.
The two reports summarized below add to the literature available to characterize the impact of
leaded aviation gasoline on air quality at and around airports in the U.S.
Key Points about the Technical Reports
• The two reports are based on the best available, recent data, and use sound analytical
methods, but they do not draw definitive conclusions about actual lead levels or risk and
should not be used to evaluate attainment of the lead NAAQS.
• The reports describe screening analyses, which are routinely used by the Agency as
initial assessments of potential health and environmental issues. The reports add to the
literature available to characterize the impact of leaded aviation gasoline on air quality
at and around airports in the United States.
• The reports will be used by the National Academy of Sciences as part of its requirement
to provide a report to Congress that assesses the air quality impact of lead emitted by
piston-engine aircraft.
2 www.epa.gov/regulations-emissions-veliicles-and-engines/airport-lead-monitoring-and-modeling
3 www.faa. gov/about/initiatives/avgas/
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Summary: Model-extrapolated Estimates of Airborne Lead
Concentrations at U.S. Airports
The report titled, "Model-extrapolated Estimates of Airborne Lead Concentrations at U.S.
Airports" was developed to provide estimated ranges of lead concentrations that may occur
at and near airports where leaded aviation gas is used. The study extrapolated modeling
results to estimate air lead concentrations at the "maximum impact area" for over 13,000 U.S.
airports. The "maximum impact area" is the assigned area at the end of the runway where
pilots are required to conduct safety checks with engines running just prior to takeoff. This
area is expected to have the highest concentration of lead in air, and in fact air monitoring has
reported concentrations of lead above the lead NAAQS near this location at some airports. The
model-extrapolated lead estimates in this study indicate that some additional U.S. airports may
have air lead concentrations above the NAAQS at this area of maximum impact. The report
also shows that estimated lead concentrations decrease to below the standard within 50 meters
from the area of highest concentration. Estimated lead concentrations from this study should
not be used to directly evaluate attainment of the lead NAAQS.
Summary: National Analysis of the Populations Residing Near or
Attending School Near U.S. Airports
The second report, titled "National Analysis of the Populations Residing Near or Attending
School Near U.S. Airports," was designed to provide an initial, national-scale understanding
of the number of people who live or attend school within 500 meters (one half kilometer)
of airport runways. This report found that approximately 5 million people live, and 163,000
children attend schools, within 500 meters of an airport runway. This report does not assess the
risk or characterize air lead concentrations for this population.
Lead and Health
• Lead exposure to children can result from multiple sources and can cause irreversible and
life-long health effects. No safe blood lead level in children has been identified. Even
low levels of lead in blood have been shown to affect IQ, ability to pay attention and
academic achievement.
• In adults, health effects from lead exposure can include cardiovascular effects,
increased blood pressure and incidence of hypertension, decreased kidney function, and
reproductive issues (in both women and men).
• EPA is concerned about aggregate exposures from all sources of lead, especially given the
persistence of lead in the environment. The information about aircraft lead provided by
these reports can help guide efforts to reduce potential exposure to this source.
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Next Steps
• EPA will provide opportunities for follow-up with State, local and tribal governments;
community organizations; and other stakeholders, as needed.
• EPA will continue to conduct outreach to help individual airports and the communities
near them understand what this information means at the local level.
• There are steps that can be and have been taken at airports to minimize the potential for
exposure to lead emissions.
• EPA will be working with airports and local air agencies, as requested, to evaluate on
a case by case basis whether further assessment of exposure and risk is needed, and if
appropriate, mitigation measures that could be considered.
• The Federal Aviation Administration (FAA) is actively working to identify unleaded
fuels for use in piston-engine aircraft. The reduction or removal of lead from this fuel is
under FAA's authority.
For More Information
The reports summarized in this fact sheet may be found here:
www.epa.gov/regulations-emissions-vehicles-and-engines/airport-lead-monitoring-and-modeling
Information on the Federal lead action plan may be found here:
www.epa.gov/lead/federal-action-plan-reduce-childhood-lead-exposure
Information about the health effects of lead may be found here:
www.epa.gov/isa/integrated-science-assessment-isa-lead
Information on the Federal Aviation Administration's Piston Aviation Fuels Initiative may be
found here:
www.faa.gov/about/initiatives/avgas/
For further information about these reports please contact Marion Hoyer, U.S. EPA, Office of
Transportation and Air Quality, at:
hoyer.marion@epa.gov
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