Under the Federal Clean Air Act (CAA) (42 U.S.C. § 7401-7671q), the United States Environmental Protection Agency (USEPA) has established National Ambient Air Quality Standards (NAAQS) for six criteria pollutants: carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), particulate matter (PM10 and PM2.5), ozone, and lead. There are no federal standards for aviation-related GHG emissions. Air quality and the emissions associated with aircraft operations, specifically lead, were a comment topic of concern from both the CAC and community.

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Lead is a poison harmful to human health. There is no safe level of lead in the blood. Lead exposure is associated with harm to the nervous, cardiovascular, immune, and reproductive systems. Lead exposure can cause anemia, high blood pressure, an increased risk of cancer, and, at high levels, death. Children are particularly susceptible to harm from low-level lead exposure, which can affect growth and cause behavioral problems and learning deficits. There is evidence that many of lead's adverse effects on children are irreversible. Lead was phased out of automotive fuels in the 1970s but is still used in aviation gasoline primarily to meet higher octane requirements and prevent engine failure in piston-engine aircraft.

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The burning of leaded aviation gasoline accounts for an estimated 70% of airborne lead emissions in the U.S. There are an estimated 170,000 piston-engine aircraft nationwide, operating out of an estimated 13,117 airports. The U.S. Environmental Protection Agency (EPA) estimated in 2020 that roughly 5.2 million people live in a census block intersecting with a 500-meter buffer around an airport runway or a 50-meter buffer around a heliport. Of those people, 363,000 are children aged 5 years and under. In addition, an estimated 573 public and private schools enrolling about 163,000 students in grades K-12 are located near an airport runway or heliport.

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While efforts are underway by the Federal Aviation Administration (FAA) and the aviation and energy industries to transition piston-engine aircraft to unleaded fuel, primarily through the recently formed Eliminate Aviation Gasoline Lead Emissions (EAGLE) initiative, the EPA proposed an endangerment finding on October 7, 2022[1], that, if adopted, would determine that lead emissions from aircraft that operate on leaded fuel cause or contribute to air pollution that may reasonably be anticipated to endanger public health and welfare. This endangerment finding is a fundamental step which will allow the EPA and FAA to regulate and ultimately eliminate the use of leaded aviation gasoline. It is supported by the FAA, aviation industry, and various organizations and public entities.

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On January 10, 2023, the Los Angeles County Board of Supervisor passed a motion protecting the public health by supporting the United States Environmental Protection Agency’s proposed regulation of leaded aviation gasoline.

Greenhouse gases (GHGs) trap heat in the earth’s atmosphere. The main GHGs are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and fluorinated gases (e.g., hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF6), and nitrogen trifluoride (NF3)).

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In 2009, the USEPA found that current and projected concentrations of the six main GHGs – CO2, CH4, N2O, HFCs, PFCs, and SF6[2] – in the atmosphere threaten the public health and welfare of current and future generations, and that combustion of fossil fuels contribute to the increase in CO2 and other GHGs in the atmosphere.[3]

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Common sources of emissions at a general aviation airport include aircraft, support equipment fueled by fossil fuel, diesel or hybrid, trucks, other vehicles, and emergency generators.  According to most international studies, aviation emissions comprise a small but potentially important percentage of human-made greenhouse gases and other emissions that contribute to global warming.  In terms of relative U.S. contribution, the U.S. General Accounting Office (GAO) reports that aviation accounts “for about three percent of total U.S. greenhouse gas emissions from human sources” compared with other industrial sources, including the remainder of the transportation section (29 percent) and industry (22 percent).[4] Using industry standard assumptions, the 2021 operations of Whiteman Airport was modeled and resulted in a total of 2,275 short tons of carbon dioxide (CO2) produced.

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By understanding the sources of emission on the airport (i.e., which aircraft are based there, the number of aircraft operations, fueling, generators, etc.), air quality monitors were placed at three locations within the airport boundaries in order to capture the most accurate readings possible for emissions, as well as to ensure the continuity and security of the monitors themselves. The sampling included passive measurements and time averaged samples which contained particulate matter 10 (PM 10), TO-13A, TO-11A, and volatile organic compounds (VOCs). The PM10 samples were also analyzed and found to contain select metals, including lead, via x-ray spectroscopy.

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In January 2015, the US EPA published a study[5] titled “Airport Lead Monitoring” which provided lead concentration data measured at 17 airports across the United States, including nearby Van Nuys Airport. The lead measured, which was averaged over a year in the study, ranged from 0.01 to 0.33 µg/m3 and Van Nuys Airport reported 0.06 µg/m3. The samples studied from Whiteman Airport range from 0.021 to 0.06 µg/m3 of lead.

It should be noted that the model only considered the airport operations. The air quality monitors were placed to best capture readings from aircraft emissions but do not eliminate emissions from other sources.

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You may read the Air Quality Study summary here​.

[1] Regulations for Lead Emissions from Aircraft | US EPA

[2] Several classes of halogenated substances that contain fluorine, chlorine, or bromine are also greenhouse gases, but they are, for the most part, solely a product of industrial activities.

[3] Endangerment and Cause or Contribute Findings for Greenhouse Gases under the Clean Air Act, 74 Fed Reg. 66495 et seq. (2009)

[4] USEPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks, 1990-2017, April 11, 2019.

[5] USEPA, Airport Lead Monitoring, January 2015, January 18, 2023.