Environmental Issues in 21st Century Aviation: Key Challenges

Introduction and Background

Environmental awareness regarding 21st-century aviation has been growing among the public and politicians since the 1960s. It became extensively documented that human activities were having damaging and large-scale effects on the environment (Suzanne & Fallacaro, 2011). Engineering and scientific research has also played a growing role in both protecting and understanding the environment. Research has established the significance of the environment to human health and well-being, along with the economic, social, and aesthetic harm that can result from poor environmental practices in aviation. Research has suggested that there are many issues, and that there are various methods to curb harmful practices without incurring unnecessarily high costs. For instance, scientific and engineering research has provided cost-effective ways to decrease water and air pollution in the United States; has established the significance of areas such as wetlands, which were once considered of little value to human societies; and has helped to preserve natural ecosystems and the species that inhabit them.

Over the years, aviation has faced numerous environmental issues. In 1983, for example, the International Civil Aviation Organization (ICAO) founded the Committee on Aviation Environmental Protection (CAEP) to evaluate aviation-associated noise and emissions issues. CAEP established three environmental objectives: reduce or limit the number of people impacted by aircraft noise; reduce or limit the impact of aviation emissions on local air quality (LAQ); and reduce or limit the influence of aviation greenhouse gas (GHG) emissions on the global climate.

The crucial aim for the industry will need to be sustainable development, where the environment is not sacrificed for growth and future generations will be able to benefit from air travel. However, the aviation industry has already begun to confront this difficult task, and continued creative effort is required to ensure the industry makes the most of its "environmental capacity."

Like any other form of public mass transport that depends on finite planetary resources, aviation cannot — in its present form — be considered sustainable in the very long term. Because of the finite nature of the resources upon which aviation depends, it is more accurate in the medium term to consider how best to improve the sustainability of air transport rather than to claim that it has attained sustainable development.

Executive Summary

Aviation is widely regarded as a critical part of the national economy, facilitating the movement of goods and people around the world and enabling economic growth. In the last 35 years, there has been approximately a six-fold increase in the mobility provided by the United States air transportation system, accompanied by a 70% improvement in aircraft fuel efficiency and a 97% reduction in the number of individuals impacted by aircraft noise.

In spite of this progress, and despite aviation's comparatively small environmental impact in the United States, there is a compelling need to address the environmental aspects of air transportation. Because of strong growth in demand, emissions of some pollutants from aviation are rising against a background of declining emissions from many other sources. Furthermore, progress on noise reduction has slowed. Millions of people are adversely affected by these side effects of aviation. These factors, combined with the rising value placed on environmental quality, are creating constraints on the nation's mobility, economic vitality, and security. In many places, plans for airport expansion have been delayed or canceled due to concerns over local air quality, water quality, and community noise.

Even military readiness is being challenged by limitations on certain operations. These effects are expected to grow as the economy and demand for air transportation continue to develop (Iani & Wickens, 2007). If this concern is not addressed soon, environmental impacts may well become the fundamental constraint on air transportation growth in the 21st century.

Overview of Airport Environmental Issues

Research shows that in the next 15 years, air travel is expected to grow substantially (Iani & Wickens, 2007). As a result, expansion and airport development projects will likely become increasingly important. A potential challenge to the success of these projects is community concern about airport environmental impacts. Airport operations involve an array of activities that affect the environment, including:

the operation of aircraft; the operation of airport and passenger vehicles and airport ground service equipment (GSE); cleaning and maintenance of aircraft, motor vehicles, and GSE; anti-icing and deicing of aircraft and airfields; fuel storage and fueling of aircraft and vehicles; airport facility maintenance and operations; and construction.

The environmental impacts of these activities could intensify if an airport is undergoing expansion. In many cases, before a local or state agency will permit an airport to proceed with a development project, the airport authority must commit to implementing positive environmental mitigation projects. Community concern about environmental impacts has caused projects to be cancelled or delayed (Iani & Wickens, 2007). All airports, regardless of location or size, are regulated to some degree under state, local, tribal, or federal environmental requirements.

Many of the environmental regulatory requirements applicable to noise, water, and air quality have been in effect for years — airport managers are accustomed to their compliance responsibilities. However, the anticipated growth in air travel has intensified the significance and complexity of some environmental regulatory matters (Pezzullo, 2005). Several new requirements are expected to result in potentially significant changes to airport operations. The most notable issues include ongoing community concern about noise, changes to Environmental Protection Agency (EPA) procedures applicable to aircraft and airfield deicing operations (Maughan & Gillingwater, 2001), and revisions to EPA regulations applicable to oil spill prevention preparedness.

Deicing and Anti-icing Activities

With regard to water quality compliance matters, the management of anti-icing and deicing chemicals has posed the greatest challenge to many airport operators. The deicing and anti-icing of aircraft and airfield surfaces is required by the Federal Aviation Administration (FAA) to ensure passenger safety. However, when performed without discharge controls in place, airport deicing procedures can result in environmental impacts (Suzanne & Fallacaro, 2011). Discharges from deicing operations have the potential to cause algae blooms, fish kills, and contamination of surface and groundwaters. In addition to potential water-life and human health impacts from the toxicity of anti-icing and deicing chemicals, the biodegradation of ethylene glycol or propylene glycol in surface waters can significantly impair water quality, including causing important reductions in dissolved oxygen levels (Woodcock & Roberts, 2007).

Studies have likewise revealed toxicological effects of deicer solutions that cannot be attributed to either ethylene glycol or propylene glycol (Westermark, 2001). This has led to concern that these effects are attributable to unknown, proprietary additives, the environmental impact and fate of which are not yet understood (Suzanne & Fallacaro, 2011). Typically, airlines are responsible for aircraft deicing and anti-icing operations, while airports are accountable for the deicing and anti-icing of airstrip surfaces. The airfield is ultimately responsible for managing the resulting wastewater, and this responsibility is typically absorbed into the airport's stormwater authority (Wayson & Iovinelli, 2009).

As noted above, significant differences exist among airport NPDES permits. A local permitting authority can impose specific requirements — for example, restrictions on where deicing operations may take place, an obligation to use deicing collection units to recover deicing fluid before it enters the stormwater system, or provisions requiring monitoring equipment to ensure permit compliance. Other permits may allow the airport to discharge deicing fluids directly into a neighboring water body (Woodcock & Roberts, 2007).

According to the EPA, the disparity in airport permitting requirements led the agency to consider applying national standards in the form of effluent limitation guidelines (ELGs) for airport deicing and anti-icing operations (Westermark, 2001). Effluent limitation guidelines are national standards for regulating wastewater discharges to surface waters. They are technology-based and industry-specific. ELGs applicable to airport deicing would be intended to deliver consistent guidance for NPDES permit writers across the country, thereby establishing a baseline standard for all airports (Wayson & Iovinelli, 2009). In 2004, the EPA began developing effluent limitation guidelines for airport deicing operations.

Initial estimates from the EPA suggest that treatment technology and pollution-prevention practices could decrease deicing discharges from the current level of 25 million gallons per year to 6 million gallons per year (Suzanne & Fallacaro, 2011). Numerous airports already have strict permit requirements stipulating the management of deicing chemicals, while others have few controls. Those with few controls may be required to make capital investments to comply with new permitting requirements.

Fuel Storage and SPCC Plans

Because airports must store fuel on-site to refuel aircraft and ground equipment, most airports are required to develop a Spill Prevention, Control, and Countermeasure (SPCC) plan (Wayson & Iovinelli, 2009). These requirements are designed to ensure that facilities storing oil have planned for and taken measures to prevent environmental harm from oil spills. An SPCC plan must include operating procedures intended to prevent oil spills (e.g., procedures to inspect tanks and associated piping for leaks) and control measures designed to prevent a spill from reaching navigable waters (e.g., construction of a dike, containment curb, or pit around a tank or tank farm).

One of the primary control measures required under SPCC regulations is the use of a secondary containment system for oil storage containers. Such a system must be large enough to temporarily hold the entire contents of the largest oil tank at the storage location in the event of a breach. For instance, if a tank farm contained four 14,000-gallon tanks, two 7,000-gallon tanks, and ten mobile refueling trucks with 500-gallon tanks, the tank farm would be required to have secondary containment sufficient to hold the contents of the largest single tank — 16,000 gallons (Wayson & Iovinelli, 2009).

When the EPA proposed new SPCC requirements in 2002, airport operators and the EPA disagreed about the secondary containment requirements applicable to mobile airport refueling trucks. In particular, airport operators argued that it was impractical to require mobile refuelers to provide secondary containment equal to the tank size because, during refueling operations, the trucks would need to move to many parts of the airfield that could not be retrofitted with secondary containment systems (Westermark, 2001).

National Pollutant Discharge Elimination System

The Clean Water Act (CWA) prohibits any "point source" — a discrete conveyance such as a drainage ditch, pipe, or outfall — from discharging pollutants into the waters of the United States (Suzanne & Fallacaro, 2011). The primary mechanism for controlling pollutant releases is the National Pollutant Discharge Elimination System (NPDES) permit program, which is administered in most cases by individual states (Peter, 2012). The NPDES permit program regulates discharges of both stormwater and wastewater. Because of the nature of their outdoor operations, and because airports fall under one of the industrial categories covered by the NPDES stormwater permitting program (under the Standard Industrial Classification code "Transportation by Air"), all airports are required to obtain a stormwater permit (Suzanne & Fallacaro, 2011).

Airports that discharge other wastewater — for example, from equipment maintenance and cleaning operations — require an additional NPDES wastewater permit. Stormwater discharges frequently pose the greatest challenge to airport managers because airports may spread across a wide surface area with most operations exposed to the elements. For instance, Dallas Fort Worth International Airport encompasses 20,000 acres and has 72 stormwater outfalls (Woodcock & Roberts, 2007). Monitoring or controlling every outfall is extremely difficult. The primary technique for managing stormwater discharges is the application of best management practices (BMPs) that prevent or reduce the release of pollutants into a water body (e.g., construction of a stormwater retention pond to prevent direct drainage into receiving waters). BMPs appropriate for one airport are not necessarily appropriate for another. Factors that may affect permit requirements include local climate, the size or type of neighboring water bodies, the water quality of those water bodies, and airport size (Suzanne & Fallacaro, 2011).