Background
Leaded gasoline for on-road vehicles was banned in 1996 through the Clean Air Act. However, small piston-engine planes still use leaded aviation fuel. These small planes are now the largest source of lead in the air. These planes typically accommodate 2-10 passengers. A 2023 EPA determination states that emissions from these planes pose environmental and health risks to communities surrounding airports. Many of these communities have environmental justice concerns.i DOH recommends health care providers test children for lead exposure if they live within a kilometer of an airport.ii
This overlay shows the location of all general aviation airports in the state that cater to small piston-engine planes. We created a 1km radius (“buffer”) around each airport and summarized the populations and schools within these buffers. The overlay will help individuals and families learn if they live or their children attend school within a kilometer of an airport. It also shows which communities are at risk of exposure to aviation fuels and where there might be environmental justice issues.
Data Sources
| Population Characteristics | Source | Year |
|---|---|---|
|
Airports |
WSDOT non-military airports (excluding SeaTac) | 2022 |
| Total population | American Community Survey | 2015-2019 |
| Children 0-5 years old | American Community Survey | 2015-2019 |
| Families living below the federal poverty level | American Community Survey | 2015-2019 |
| People of color | American Community Survey | 2015-2019 |
| Households with primary languages other than English | American Community Survey | 2015-2019 |
| Foreign born | American Community Survey | 2015-2019 |
| Daycares | Department of Children, Youth and Families | 2023 |
| Public schools | OSPI school directory | 2021 |
| Private schools | Washington private schools directory - WFIS | 2022 |
Methods
We used population characteristics at the census block group level to ensure a fine spatial resolution. We chose this geography to minimize errors in population estimation within buffer zones. To calculate population counts within the 1km buffers, we used an area-weighted population apportionment method. The percentage of area of each block group covered by the buffer serves as a proxy for the percentage of the population living in the buffer zone. We arrived at the approximate count of the population within each buffer by adding together the covered proportion of each block group. Here is a visual example of the area-weighted population apportionment for a fictitious airport:
In the above example, 50% of the area of block group 1, 20% of block group 2 and 75% of block group 3 fall within the buffer. The population within the buffer is then estimated as:
0.5 * PopulationBG1 + 0.2 * PopulationBG2 + 0.75 * PopulationBG3 =Population in Buffer
For schools and daycares, we summarized the number within the buffer of each airport. We separated out the number of elementary schools from the total number of schools due to the higher risk of negative health outcomes associated with lead exposure in younger children. Looking at both the total population and vulnerable populations helps identify potential exposure risks in communities surrounding airports hosting small piston-engine planes.
Summary/Findings
The information for each individual airport on the overlay. Here are statewide summary statistics to provide context (see table below).
Population in Buffer Zones: A total of 132,689 individuals live within the 1km buffer zones around airports. This is 1.79% of Washington state residents.
Educational and Childcare Facilities: Within the buffer zones, there are 8 private schools, 44 public schools (including 12 elementary schools), and 29 childcare centers.
|
1km Airport Buffer n (%) |
Washington State n (%) |
|
|---|---|---|
| Total population | 132,689 | 7,404,107 |
| Population 5 and under | 5,867 (4%) | 454,364 (6%) |
| People of color | 47,509 (36%) | 2,330,162 (32%) |
| Foreign born | 26,190 (20%) | 1,056,534 (14%) |
| Total families | 28,528 | 1,841,954 |
| Families living below federal poverty level | 1,508 (5%) | 127,119 (7%) |
| Total households | 64,262 | 2,848,396 |
| Households with primary languages other than English | 2,515 (4%) | 108,151 (4%) |
Contact
If you would like additional information or access to this data set, email Washington Tracking Network.
i United States Environmental Protection Agency. (2023, Oct 18). EPA Determines Lead Emissions from Aircraft Engines Cause or Contribute to Air Pollution. EPA News Releases. https://www.epa.gov/newsreleases/epa-determines-lead-emissions-aircraft-engines-cause-or-contribute-air-pollution
ii Washington State Department of Health. (n.d.). Blood Lead Testing Information for Health Care Providers. https://doh.wa.gov/public-health-healthcare-providers/healthcare-professions-and-facilities/professional-resources/blood-lead-testing