Seatac's Air Pollution: A Dangerous Reality

A study by the University of Washington has found that communities near the Sea-Tac Airport are exposed to a unique mix of air pollution associated with aircraft. Ultrafine particles emitted by jets and vehicles can be mapped to show their geographic footprint around the airport. These particles are less than 0.1 microns in diameter and have been linked to adverse health effects, including breast cancer, heart disease, and lung conditions. While the air quality in SeaTac is generally considered acceptable, sensitive groups may experience symptoms such as difficulty breathing or throat irritation due to high levels of pollution. To improve air quality in the region, the airport has implemented initiatives such as switching to renewable natural gas and offering greener transportation options.

Ultrafine particle pollution from jets

Ultrafine particles, or nanoparticles, are defined as particles with an aerodynamic diameter smaller than 0.1 micrometres. They are currently the most abundant particulate pollutants in urban and industrial areas. Jet engine exhaust is a significant source of ultrafine particles, and aviation-related emissions can negatively impact air quality over large areas surrounding airports.

A University of Washington study, Mobile ObserVations of Ultrafine Particles (MOV-UP), examined the air quality impacts of aircraft traffic on communities within 10 miles of Seattle-Tacoma International Airport (Sea-Tac Airport). The study found that communities underneath and downwind of jets landing at the airport are exposed to a type of ultrafine particle pollution that is distinctly associated with aircraft emissions. Ultrafine particles from jets have unique characteristics, including smaller particle sizes and lower black carbon concentrations compared to roadway air pollution.

The MOV-UP study collected air samples at various locations around Sea-Tac Airport over a year between 2018 and 2019. They developed a method to distinguish between pollution from jet traffic and other sources, such as roadway traffic. The researchers mapped each type of emission mixture to show its geographic footprint, revealing that communities near the airport are exposed to higher proportions of smaller-sized, "ultra-ultrafine" pollution particles. These particles are 700 times thinner than a human hair and can spread over a more extensive area than pollution particles from roadways.

The health effects of ultrafine particles are a growing concern. Ultrafine particles can inhibit phagocytosis, stimulate inflammatory responses, damage epithelial cells, and potentially access the interstitium. Studies near airports have shown an increase in outdoor and indoor ultrafine particle concentrations, indicating a need for further research to characterise these impacts better and develop interventions to reduce human exposure.

Ultrafine particle pollution from vehicles

Ultrafine particles, which are about 700 times thinner than a human hair, are a major concern for air pollution experts. These particles can be spread through wildfire smoke, vehicle exhaust, industrial emissions, and airplane fumes. They can bypass the body's natural defenses, carrying toxins to every organ or burrowing deep into the lungs.

A recent study by the University of Washington found that the highest concentrations of these particles are in areas with a history of redlining, which are neighborhoods that were once considered undesirable for racial minorities and low-income residents. These areas tend to have higher populations of Black residents and lower median household incomes. The study also found that neighborhoods near industrial areas had ultrafine particle concentrations that were 49% above average.

Vehicle exhaust is a significant contributor to ultrafine particle pollution in Seattle. A study by the UW School of Public Health examined the air quality impacts of aircraft traffic on communities located within 10 miles of Sea-Tac Airport. The researchers found that communities under flight paths near the airport are exposed to higher proportions of smaller-sized, 'ultra-ultrafine' pollution particles, affecting a larger number of people.

While roadway air pollution particles tend to disperse over short distances, aircraft emissions consist of relatively smaller ultra-ultrafine particles that can spread over larger areas. The study's findings can inform interventions to reduce human exposure to these harmful pollutants and pursue equitable health outcomes for all Seattle residents.

Health effects of ultrafine particle pollution

Ultrafine particles (PM0.1) are present in the air and pose a significant health risk. These particles are less than 0.1 micrometres in diameter and are classified as nanoparticles. They are a major component of air pollution, particularly in large cities, and can have severe impacts on human health.

Due to their extremely small size, ultrafine particles can easily enter the body through the lungs and translocate to other organs. They have a greater tendency to stay in the lungs for longer periods compared to larger particles, causing more inflammation and cellular toxicity. Ultrafine particles have been linked to respiratory conditions and can trigger asthma and cough. They also cause systemic inflammation, endothelial dysfunction, and coagulation changes, increasing the risk of ischemic cardiovascular disease and hypertension.

The tiny size of ultrafine particles allows them to bypass the body's natural defences, such as the filtering mechanism of the nose, and reach the small airways and alveoli. Deeper breathing can promote the deposition of these particles in the alveolar region, increasing the likelihood of adverse health effects. Animal studies have shown that a small fraction of insoluble ultrafine particles deposited in the lungs can rapidly translocate to other organs, including the liver, spleen, kidneys, heart, and brain.

The health effects of ultrafine particles can vary among individuals, with some studies suggesting that genetic background may play a role in the response to particle pollution exposure. While the immediate effects of fine particles (PM2.5) are more pronounced, ultrafine particles have more delayed effects and a greater influence on mortality. The lack of standardised measuring instruments and international standards makes it challenging to fully understand the long-term health consequences of ultrafine particle exposure.

In summary, ultrafine particle pollution has significant adverse health effects, including respiratory ailments, cardiovascular changes, and potential impacts on multiple organs. The small size of these particles allows them to evade the body's defences and reach vital organs, causing inflammation and toxicity. Further research and standardised measurements are needed to fully comprehend the long-term health implications of ultrafine particle exposure.

Proximity to Sea-Tac Airport

Sea-Tac, short for Seattle-Tacoma International Airport, is the eighth-busiest airport in the United States. In 2018, the airport served nearly 50 million passengers and saw 438,391 takeoffs and landings. A study by the University of Washington found that communities within 10 miles of the airport, particularly those underneath and downwind of jets landing at Sea-Tac, are exposed to a unique mix of air pollution associated with aircraft.

The two-year Mobile ObserVations of Ultrafine Particles or "MOV-UP" study, funded by the Washington State Legislature, examined the air quality impacts of aircraft traffic on communities near Sea-Tac Airport. Researchers from the UW Department of Environmental & Occupational Health Sciences and the Department of Civil & Environmental Engineering collected air samples at various locations around the airport between 2018 and 2019. They developed a new method to distinguish between pollution from jet traffic and pollution from other sources such as roadway traffic.

The study found that communities under the flight paths near the airport are exposed to higher proportions of smaller-sized, 'ultra-ultrafine' pollution particles compared to pollution from roadways. These ultrafine particles are less than 0.1 micron in diameter, or 700 times thinner than the width of a single human hair. Ultrafine particles have been linked to various health issues such as breast cancer, heart disease, prostate cancer, and lung conditions.

While the MOV-UP study did not directly investigate the health effects of pollution exposure, it has provided valuable data for future research. Professor Michael Yost, a co-investigator on the study, emphasized the importance of understanding the specific health impacts of aircraft-related pollution and exploring interventions to reduce human exposure to these pollutants. Yost aims to collaborate with policymakers and affected communities to address these concerns.

Air quality data and monitoring

The air quality data and monitoring in SeaTac, Washington, is an important aspect of ensuring the well-being of its residents. SeaTac's air quality is influenced by various factors, including aircraft emissions and roadway traffic.

Data Sources and Monitoring Methods:

SeaTac's air quality data is obtained from various sources, including:

• Plume Labs: Plume Labs provides raw air quality data and information to platforms like AccuWeather. This data includes current indices, forecasts, and daily and hourly air quality measurements. While AccuWeather aims to provide accurate information, it disclaims legal liability for the accuracy of the data, which is subject to change.
• IQAir: IQAir is another source of air quality data, offering a SeaTac Air Quality Index (AQI) and information on the main pollutant, PM2.5. They also provide a platform for individuals to purchase monitors and contribute air quality data in their cities.
• University of Washington Study: A specific study, "Mobile ObserVations of Ultrafine Particles" (MOV-UP), funded by the Washington State Legislature, focused on the air quality impacts of aircraft traffic on communities within 10 miles of Sea-Tac Airport. This study collected air samples at various locations and developed a method to distinguish between pollution sources.

Air Quality Index (AQI) and Standards:

The Air Quality Index (AQI) is a critical tool for understanding air quality. In SeaTac, the AQI values are calculated by Plume Labs using standards and guidelines from the Environmental Protection Agency (EPA) and the World Health Organization (WHO), as well as their own scientific studies. The AQI provides a quantitative measure of air quality, helping residents and authorities make informed decisions.

Real-time Data and Mapping:

Both AccuWeather and IQAir strive to provide real-time air quality data and mapping. AccuWeather's air quality maps are updated as soon as practical, displaying current indices, forecasts, and hourly data. IQAir also offers a real-time, 3D animated air pollution map through its IQAir Earth platform. These tools enable residents to stay informed about the air quality in their area.

Health Implications:

The air quality in SeaTac can vary, and while it is often acceptable for most individuals, sensitive groups may experience symptoms with long-term exposure. High levels of pollution can cause issues such as difficulty breathing and throat irritation, especially for sensitive individuals. It is recommended that those experiencing symptoms reduce their time spent outdoors during such periods.

Frequently asked questions