Airports And Air Quality: The Pollution Problem

Airports are a major source of air pollution, which has a significant impact on the health of workers, residents, and the environment in the surrounding areas. The aviation industry's emissions, particularly from aircraft and ground vehicles, contribute to elevated levels of ultrafine particulate matter (UFP), black carbon, nitrogen oxides (NOx), and other harmful pollutants. Aircraft taxi time and congestion also play a role in increasing local ambient air pollution. The impact of airport pollution extends beyond the airport vicinity, as studies show higher particle number concentrations within nearby residences. To address these issues, airports are implementing measures such as modernising power plants and vehicles, reducing fuel consumption, and collaborating with aircraft manufacturers to meet efficiency targets and emission standards.

Aircraft emissions

Aircraft emit various gases and particles that impact air quality, including carbon dioxide (CO2), nitrogen oxides (NOx), water vapour, black carbon, and particulate matter. The combustion of jet fuel, such as Jet A1, is a major source of these emissions. Additionally, ground service vehicles, such as those used for baggage handling and refuelling, contribute to diesel emissions.

The impact of aircraft emissions on air quality is influenced by factors such as flight altitude and location. A study by the Massachusetts Institute of Technology (MIT) found that carbon dioxide, nitrogen oxides, and water vapour from condensation trails released at cruising speed have the most significant impact on air quality.

The commercial aviation industry is experiencing rapid growth, with passenger traffic increasing by 4.7% annually, according to the International Civil Aviation Organization (ICAO). This increased demand has led to a rise in aviation emissions over time. Between 1990 and 2019, direct CO2 emissions from fossil fuel combustion in aviation increased, with a slight decrease during the COVID-19 pandemic due to reduced air travel. However, as demand rebounded, emissions also increased, and they are expected to surpass pre-pandemic levels.

To address the environmental impact of aircraft emissions, several measures are being explored and implemented. These include the development of sustainable aviation fuels (SAFs), improvements in engines and airframes, operational optimizations, and the promotion of alternative modes of transport, such as rail. Additionally, the use of electric or hydrogen-powered aircraft is being explored, with successful tests of hydrogen-powered engines conducted by companies like Airbus, Rolls-Royce, and easyJet.

While aviation currently contributes approximately 2.5% of global CO2 emissions, its overall impact on warming is higher due to non-CO2 forcings, such as contrails. Therefore, addressing aviation emissions is crucial in mitigating climate change and improving air quality, particularly in areas surrounding airports.

Ground-based emissions

Airports are among the largest sources of air pollution in the United States. Ground-based emissions from cars, trucks, buses, and other vehicles are major contributors to poor air quality around airports. In fact, studies have shown that up to 95% of local particulate matter comes from these ground vehicles rather than aircraft. Airports are major business sites with a high volume of employees and passengers, and the traffic generated by airports contributes significantly to congestion and pollution in the surrounding areas.

The main emissions affecting air quality at airports come from diesel and Jet A1 fuel used in ground service vehicles and aircraft, respectively. These emissions include ultrafine particulate matter (UFP), which has been found to be highly elevated at and around airports. UFP consists of microscopic solid and liquid substances suspended in the air, and it poses serious health risks to those who work outdoors at airport facilities and those living in the vicinity.

To reduce the impact of ground-based emissions, airports are taking several mitigation measures. Many airports are modernizing their power plants, ground equipment, and vehicle fleets. Diesel and petrol vehicles are being replaced with alternatives such as electric, hydrogen, or compressed natural gas options. Airports are also working with local authorities to reduce road traffic, improve ground traffic flow, and promote greener methods of transport to and from the airport.

Additionally, the International Civil Aviation Organization (ICAO) sets standards for nitrogen oxide emissions and regularly tightens them for each new generation of aircraft. Airports are also collaborating with aircraft and engine manufacturers to further reduce emissions and noise impacts on local communities. These collective efforts are crucial in minimizing the environmental and health impacts of ground-based emissions at and around airports.

Noise pollution

Airports are among the largest sources of air pollution in the United States. Aircraft noise is one of the most detrimental environmental effects of aviation. Aircraft noise pollution refers to the noise produced by aircraft in flight or on the ground, which has been linked to several negative health effects, from sleep disorders to cardiovascular disorders and increased stress.

A study of 2844 children aged 9-10 years from schools around London Heathrow, Amsterdam Schiphol, and Madrid Barajas airports found exposure-response associations between aircraft noise and poorer reading comprehension and recognition memory. A 5 dB increase in aircraft noise exposure was associated with a 2-month delay in reading age in the UK. In addition to the health effects on children, aircraft noise can cause community annoyance, sleep disruption, and an increased risk of cardiovascular disease for people living near airports.

To address these issues, governments have implemented regulations and controls targeting aircraft designers, manufacturers, and operators, resulting in quieter aircraft and improved operating procedures. For example, the US FAA Aircraft Certification program achieved noise reductions with "Stage 3" and "Stage 4" noise certifications, with Stage 4 being the quietest. Some airports, such as San Francisco International Airport and San Jose International Airport in California, have also implemented programs to insulate homes near airports, reducing indoor noise exposure.

Night flying restrictions at Heathrow, Gatwick, Stansted, and Frankfurt airports also help to reduce noise exposure during sleep hours. Additionally, advancements in engine technology, such as modern high-bypass turbofan engines, have led to significant noise reductions. NASA is working towards further noise reduction, aiming for a cumulative 20-30 dB decrease below Stage 4 limits by 2026-2031.

While these measures have helped mitigate noise pollution, it is important to continue implementing strategies to minimize the impact on nearby communities and the environment.

Health risks

Airports are considered to be one of the biggest sources of pollution in the United States. They are major business sites with many employees and passengers, and the emissions from aircraft and ground vehicles contribute to worsening air quality.

The health risks associated with airport air pollution are significant and wide-ranging. Research has linked air pollution from airports to an increased incidence of respiratory illness, cardiovascular issues, and lung cancer. For example, a study of individuals living near SeaTac Airport found lower life expectancy and an increased risk of health problems such as stroke, heart disease, and respiratory issues. Similarly, a study of women living near LAX airport found that those with greater exposure to airport air pollution had a 14% higher risk of preterm births, which can lead to a range of health problems for newborns, including heart, lung, and brain development issues.

Another study by Yim et al. (2015) attributed approximately 16,000 premature deaths per year globally to aviation emissions, with 87% associated with PM2.5 exposure. This study concluded that about a third of these deaths occurred within 20 kilometers of an airport, demonstrating the localized impact of airport pollution. Ultrafine particles from aircraft emissions and airport-related traffic congestion have been identified as major contributors to poor air quality and the associated health risks.

Noise pollution from aircraft is also a health concern for people living near airports and airport employees, as it can cause stress and other health problems.

Mitigation Measures

To address these health risks, airports are working with aircraft and engine manufacturers to reduce emissions and noise impacts. Efficiency targets to reduce fuel consumption and cut greenhouse gas emissions will help lower pollutants such as nitrogen oxide and carbon monoxide. Airports are also implementing their own policies, such as encouraging the use of electric vehicles on-site and setting targets for increasing the use of public transport for passengers. However, these efforts are often limited in scope, and more stringent measures may be needed to ensure effective air quality improvements.

Climate change

Airports and their operations have a significant impact on air quality and, consequently, on climate change. Aircraft emissions contribute to the deterioration of air quality, particularly in areas surrounding airports. These emissions include a range of pollutants such as nitrogen oxides (NOx), particulate matter (PM), carbon monoxide (CO), and volatile organic compounds (VOCs). The combustion of jet fuel, which powers aircraft engines, is the primary source of these pollutants.

Nitrogen oxides are known to have detrimental effects on both human health and the environment. They are responsible for the formation of ground-level ozone, a major component of smog, and fine particulate matter, which can penetrate deep into the respiratory system. Airports often become hotspots for elevated NOx concentrations, affecting nearby communities and ecosystems.

Particulate matter, especially the smaller particles, can pose even more significant health risks. These particles can enter the bloodstream and contribute to cardiovascular and respiratory diseases. Aircraft engines emit ultrafine particles, which have been linked to an increased risk of heart and lung problems. The concentration of these particles is typically higher in areas close to airports, subjecting residents to potential long-term health issues.

Additionally, carbon monoxide and volatile organic compounds play a role in reducing air quality. Carbon monoxide can affect the body's ability to transport oxygen, causing potential health issues, especially for individuals with heart or lung conditions. VOCs, on the other hand, can react with NOx to form ground-level ozone, exacerbating respiratory problems and damaging crops and ecosystems. The cumulative impact of these emissions from airports contributes to local and regional air pollution, with consequences for human health, ecosystems, and climate change.

To mitigate these impacts, airports and the aviation industry are exploring and implementing various measures. These include the adoption of newer, more fuel-efficient aircraft, the development of sustainable aviation fuels, and the optimization of flight routes and procedures. Airports are also investing in electric or low-emission ground support equipment and promoting the use of public transportation to reduce ground emissions. Additionally, carbon offset programs and emissions trading systems are being utilized to address the industry's carbon footprint.

In summary, airports contribute to air pollution and climate change through aircraft emissions and related operations. However, ongoing efforts to reduce these impacts are crucial to ensuring the sustainability of the aviation industry and protecting the environment and public health. A comprehensive approach involving technological advancements, operational efficiencies, and sustainable practices is necessary to minimize the climate change impacts of airports and support a greener future for aviation.

Frequently asked questions