Abstract
Aviation is a crucial component of any nation’s economy. It provides transportation and movement of goods and people from all over world, for business, imports, exports, and tourism. However, these economic benefits must be weighed against the local and global environmental impacts of this industry. There has been a remarkable effect on the global carbon emissions, and this trend is feared to multiply as more people travel by air in the modern world. The U.S. transportation system alleges that there has been an increase of up to six-fold in the aircraft mobility for the last 35 years.
Introduction
Air and noise pollution, from airport ground operations and aircraft, cause problems for people who work, live or study around airports. These effects are predicted to grow as global economies and air transport demands grow. If these issues are not addressed, the environmental impacts may as well be the constraints on aviation growth in the era of the 21st century. Plans to expand airports have been seen delaying or canceled as a result of concerns over air and water quality, and noise impacts on the community. Such restrictions have even challenged military operations. As this industry grows, there is a need to develop better environmental management policies. The step will reduce the effects on the environment with the aim of enabling the industry to grow in a sustainable way leading to sustainable aviation (Mayerowitz, 2014).
Aviation industry makes one of the sources of carbon dioxide emissions that present a big threat to international targets of emissions growth. First, it’s because the aviation industry is predicted to have rapid growth both in the past few decades and in future. Secondly, emissions delivered by aircraft at altitude have a greater impact on climate change compared to ground level emissions. Lastly, no practical alternative exists for kerosene jet fuel engines that are currently on the horizon.
The industry has consistently developed and delivered improvements to reduce environmental effects of its operations. More quiet and fuel efficient technologies are incorporated in the current and future aircraft building. Improved airspace design, operational procedures and navigational accuracy present a strong potential to decrease the environmental effects caused by the aviation industry. An immediate and focused action is, therefore, required to address the challenges of aviation air quality, noise and climate quality. Without taking action for responsibility, not only will millions of people be affected, but serious negative environmental impacts will be witnessed. A global social responsibility and strategic plan of action need to be formulated. This paper looks into the environmental issues related to the aviation industry and the social responsibility of the industry concerning the situation. The three important issues that this research has focused on include; air pollution (emissions), noise and environmental health and safety.
Air Pollution (Emissions)
Aircraft engines emit particulates and gasses, which in a broader view, contribute to global warming and climate change. Despite the efforts to reduce emissions from automobiles with less polluting turboprop and turbofan engines characterized by high fuel efficiency, aviation has contributed to more pollution attributed to growth in air travel. By burning increased quantities of fuel, aircraft engines produce carbon dioxide, oxides of nitrogen, sulfates, and particulate matter. All this pollutants amplify the effect of the aviation industry on the environment and are directly emitted into the environment. The combined effect from all these pollutants increases the global warming effect of aviation, making the industry responsible for approximately 5% of global pollution (Rosenthal, 2013).
Aircraft manufacturers are currently striving to design new generation aircraft engines that produce lower emissions, representing an opportunity to lower emissions into the atmosphere. Addition of an electric drive to the aircraft nose wheel has improved fuel efficiency at ground handling, which enables taxiing of an aircraft without the main engine (Steve, 2012). Another opportunity employed by the aviation industry to minimize emissions is through optimizing airline timetables, airspace, flight frequencies and route networks to multiply load factors and reduce the number of empty seats. The international standards for gaseous pollutants and smoke are provided by the International Civil Aviation Organization (ICAO), for production of new, large jet engines. The organization also restricts venting of raw fuels. Reductions in pollutants from aircrafts have been lower in the recent past years compared to other sectors where use of technologies such as exhaust gas recirculation and selective catalytic reduction are being employed (Wolfram et al, 2011).
Emissions of nitrogen oxides, particulate matter, carbon monoxide and unburned hydrocarbons from various airport sources have contributed to air quality deterioration, welfare impacts, and human health impacts. Several technological measures have been taken by the industry to try and minimize their levels of emissions. The many opportunities existing for operational and technological improvements geared towards the reduction of emissions present major engineering, cost and safety challenges that have to be overcome. The late models of aircrafts are more fuel efficient than their predecessors, and, therefore, emit less carbon (IV) oxide and oxides of nitrogen (Rosenthal, 2013). One of the factors that were considered in the design of the new airline, Boeing 737 aircraft, and Airbus A320, was low emission of oxides of nitrogen. GE Aviation Company, the manufacturer of the airlines, was able to produce the double annular combustor (DAC). The DAC introduced is can burn fuel in two stages at lower temperatures, instead of the conventional single stage combustors, radically reducing the level of nitrogen oxides produced. Based on this technology, GE introduced a new combustor of the twin-annular premixing swirl (TAPS).The unique TAPS concept has further reduced emission levels of nitrogen oxides emitted, a package that has improved aircraft performance (Wolfram et al, 2011).
Another available option used by the aviation industry to reduce the environmental impact is through limitation of aircraft flight altitude. Significant decrease in high altitude contrails, thus, a marginal trade-off of multiplied flight time and increase in Carbon (IV) oxide emission. Today, various governments, through balanced programs, are seeking to reduce the environmental risks that arise from aviation. Such actions require international cooperation with the active role encouraging development of innovative solutions (Rosenthal, 2013).
Aircraft Noise
In the history of aircrafts, noise has been the main environmental concern for aviation and remains a top agenda in public debate. The issue is difficult to evaluate because of its openness to subjective reactions. As opposed to the other issues, it has a short lasting impact, though it has significant effects on the population that live near an airport facility. The adverse effects include; communication interference, annoyance responses, performance effects, sleep disturbance, learning acquisition and, psycho-physiological and cardiovascular effects (Steve, 2012).
In order to understand average noise levels, computer programs are usually used to make models that “virtually” simulate an aircraft following the operational procedures of the airport. The widely used international model, the international noise model, produces noise footprints based on the number and type of aircraft to calculate the level of noise around the airport (Steve, 2012). The noises “contours” are then placed on population maps to establish which communities are faced with average noise levels and to what extent. Note that the average conditions rarely exist and, therefore, the noise contours typically indicate the noise impact. The unit for measuring noise levels is decibels (dB), which attempts to reflect the human reaction to noise “loudness”. The effective perceived noise (EPNdB) and perceived noise (PNdB) scales incorporate varied duration and frequencies of noise patterns that result from different modes of aircraft operations and speeds. The international Civil Aviation Organization (ICAO) implements the EPNdB scale to express standards for noise certification. All commercial airlines must meet the noise certification standards that have been provided by the International Civil Aviation Organization's (ICAO's). These standards are applied in aircraft types and designs when they are being approved for use (Wolfram et al, 2011). The standards are progressively being tightened since its adoption in 1971. A 33rd ICAO Assembly came up with Resolution A33/7, which introduced the concept of “balanced approach” to management of noise. The resolution established an approach policy to address aircraft noise. The concept of ‘balanced approach’ in aircraft noise management is comprised of four principal elements. The four elements include; source reduction, land use-planning and management, noise abatement procedures for operation and operation restrictions (Mayerowitz, 2014). These principles demand keen assessment procedures before a move to mitigate aircraft noise. Other measures that are commonly applied in the management of aircraft noise in the aviation industry include:
- Monitoring of individual noise levels and taking necessary measures in case of any breach
- Application of different operational charges that are based on the aircraft level of noise
- Provision of noise insulation for residential areas that are severely affected
- Avoiding flying over sensitive areas such as schools and hospitals
- Depicting the preferred noise routes that avoid resided areas as much as possible
- Ensuring that the optimum routes and runways are far as conditions can allow
- Use of departure noise abatement techniques and continuous descent approaches
- Avoiding unnecessary switching on of auxiliary power units when the aircraft is on-stand.
- Building engine test pens and barriers to deflect and contain noise
- Limiting aircraft operations during night hours
- Using towing aircraft instead of getting engines to taxi.
- Limitation of the number of aircraft operations and extend of critical noise contour.
Unless several aircrafts follow a single route, aircrafts flying at least above 10,000 feet above the ground produce insignificant noise impact. However, due to the subjective nature of noise disturbance and wide variation of many factors, this is a non-obsolete rule. In most cases, aircraft noise is associated with locations with airport facilities, where low flight heights are usually experienced. Thus, noise is the primary constraint on operation and expansion of airports. Many airports tend to put air quality concerns and noise on equal footing. Aircraft noise is generated by the propulsion system (Steve, 2012). GE Airline Company is employing the use of advanced fan designs and parts that can lower the noise produced by aircraft engine. The classic case is the engine design of the Boeing 777. This aircraft model has the largest fan blades in aviation. The fan blades create an unprecedented quantity of air flow through the aircraft engine to improve fuel efficiency. Combined with the greatest pressure ratio compressor, its large fan blades rotate slower, producing very low noise of engines powering the jumbo jets. Furthermore, the exhaust air from the engine moves at a very low speed. Hence, low noise is produced. The plans to introduce a new exhaust nozzle will significantly reduce aircraft noise. Chevron nozzle technology for GE improves the exhaust gas mixing in the engine, leading to reduced levels of noise (Wolfram et al, 2011)
Environmental Health, Passenger and Aviation Personnel Safety
The aviation industry has set various operational codes of practice for flight crew, operators and ground handling agents to minimize the impacts of aircraft operation to ensure their safety and that of the environment. The practice guideline has been compiled by aerospace manufacturers, civil aviation authorities, air traffic control, airports, airlines and environmental research and consultancy groups (Rosenthal, 2013). It provides the appropriate advice on aircraft operations at the ground and departure phases of a flight. It includes Preconditioned Air (PCA), Auxiliary Power Units (APUs), Continuous Climb Operators (CCO) and Airport Collaborative Decision Making (A-CDM). All this technical aspects are meant to ensure that the aircraft personnel, passengers, and environmental health are well taken care of to minimize the social impacts of the aviation industry (Mayerowitz, 2014).
It is recommended that ground handling agents and operators employ the ground power hierarchy where terminal based PCA and FEGP are preferred, followed by mobile ground-based Ground Power Units and air conditioning trucks, then aircraft APUs. The APUs can burn approximately six times more fuel than GPUs; hence, significant savings can be achieved. GPUs emit more emissions compared to terminal based FEGP. The aircraft operating crew have to be made aware of the lack of PCA or FEGP, or both, at the airport earlier before arrival on stand after landing or before departure. It is important that the ground handling agents, aircraft operators and airport authorities work together and ensure that all aviation personnel are properly and safely trained to use terminal-based facilities and ground. All sources of power and air condition should be adequate, fit and well maintained for their purpose. Operation crews should ensure that the APUs and main engines are switched off upon arrival at the final parking position when the ground power is available, and it is safe (Pettersen 2010). APUs is not to be started at departure, until the last moment when there is consistency with safe environmental conditions. The main engine should similarly be delayed, until the moment during the pushback series. The aircraft configuration is set to draw a very low load, e.g. by switching off Environmental Control Systems, In-Flight Entertainment and other unnecessary loads. These must be done in a manner consistent with passenger and personnel safety and welfare. Cabin blinds are shut down during turnarounds to aid reduction of heat builds at hot locations whenever possible. The Standard Operating Procedures should contain information, backed with guidance, regarding the significance of using air supplies and ground-based power. The operators should adapt the inclusion of automatic starts for engines as part of SOPs. Aircraft with four engines should be investigated for the possibility of starting two engines simultaneously, to make sure that all the safety concerns are properly addressed (Mayerowitz, 2014).
Conclusion
As far as the aviation industry is concerned, it remains one of the most economies driving factor globally. But just like an oil refinery and a power plant, it is dirty. As other economic sectors fight to reduce emissions, aviation industry is largely becoming responsible for a greater proportion of global emissions. However, effective and collaborative environmental management systems have to be set up to reduce the effects impacted by this industry to the environment. It is a collective social responsibility of all the stakeholders in the industry to ensure that the effect of these impacts is minimized.
References
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