Global warming is having negativeimpact on wildlife and humans, distorting the ecosystems, triggering natural disasters, and causing damaged food supply and health problems.Pollution resulting from aviation industry plays a major role in climate change as a result of atmospheric pollution.As countries develop to attain modern status, air traffic is also increasing at an alarming rate. Consequently, this is raising concerns about air pollution and its severe health effects on the population neighbouring the big airports. However, the greatest risk is actually the occupational exposure due to closeness. Current studies and research are neither plentiful enough nor convincing enough to ascertain the kind of danger posed by increased emissions from the airlines. Yet, the number of people working in the airports keeps increasing and new airports being created. This makes occupational exposure to aviation pollutions a fact. A research at the Massachusetts Institute of Technology established that air pollution leads to 13,000 premature deaths in Britain annually (Pope et al, 2009). These aviation carbon emissions are harmful to the atmosphere, and in large extent they contribute to global warming.
Air pollution, as defined by Pope et al (2009), is contamination of the interior or outdoor environment by any physical or biological agent, or chemical in gaseous form that modifies the natural features of the atmosphere p.376.It normally occurs when any harmful substances in form of gases, dust, or smoke are released into the atmosphere making it difficult for plants, animals and humans to live as the air gets contaminated.Common sources of air pollution include; household combustion devices, motor vehicles emissions, airline emissions, industrial effluents and forest fires. Pollutants that pose great threat to public health include particulate matter, carbon monoxide gas, ozone, sulfur dioxide and nitrogen dioxide (Jacobson et al, 2013).
Airline and the Air Pollution
Different researchers’ teams have focused their attention on the general characterisation of air pollution in the main airport regions and their surroundings. The accumulation of particulate pollutants appears to be inversely proportional to the distance from the airport, the longer the distance from the airport, the lower the concentration of pollutants. It has been established that heavy airplane traffic cause air pollute for a significantly broader area than previously established and in quantities that are corresponds to that produced by several hundreds of kilometres of freeway traffic (Westerdahl et al, 2008).
While pollution from most source areas are decreasing due to strict implementation of various federal, state, and local regulatory programs, the rapid development in air travel and the lack of appropriate technology for controlling and monitoring airline emissions is resulting in increased pollution from aviation.For a period of a century and half, human activities have increased carbon dioxide into the atmosphere to such high levels than they have been for hundreds of thousands of years before (Westerdahl et al, 2008).The United States Environmental Protection Agency (USEA) has established that airlines’ greenhouse gas emissions pose a great threat to human health (Jacobson et al, 2013). This crucial finding allows the USEA to develop a policy to limit harmful emissions from airlines as it has done with motor vehicles and power generators. Researchers have found some of the worrying particle levels, 6 to 8 times beyond normal levels within a few kilometres of the some of the busy airports(Graham, Hall & Morales, 2014).. Some findings of almost 10 times above ordinary were measured in pockets closest to Los Angeles International Airport. Levels measuring up to double the normal level were identified at a distance of 10 miles from the airport.
The European Union acknowledged the seriousness of aviation pollution and passed a regulation requiring all airlines flying in and out of Europe to reduce their pollution to a particular level. This pollution directive is the only program in the world established to reduce and check aviation pollution. All airlines, either landing or taking off from European Union airports expected to adhere to the set regulation failure to which might amount to big fines.. In addition to significantly reducing carbon emissions, this law generates a larger debate about pollution caused by aviation industry. Abiding by the regulation is comparatively low-cost for airlines and encourages the development of better fuel efficiency technologies and use of green energy sources to replace petroleum fuel.
Airline jet engines, like numerous other transportation sources, produce carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOx), sulfur oxides (SOx), unburned or partially combusted hydrocarbons (also referred to as volatile organic compounds, or shortly VOCs, including polycyclic aromatic hydrocarbons (PAHs)), particulate matter, and other trace compounds (Graham, Hall & Morales, 2014). All these pollutants are released at varying rates during different phases of airline operation, such as landing, idling, taxing, take-off, and climbing. Normally, NOx emissions increase during high power operations such as aircraft take-off when combustor temperatures are considered high. On the other hand, carbon monoxide emissions are considered high during low power operations such as taxiing when combustor temperatures are low and the engine is less efficient (Graham, Hall & Morales, 2014). Although the aircraft engine is often idling during the events of taxi-out, the per minute carbon monoxide and nitrogen oxide emissions factors are normally higher than at any other period of a flight (Jacobson et al, 2013). Merging this with the extended duration of taxi-out times especially during peak periods of the day, the total taxiing over the span of a day can equate to a substantial amount.
Clean air Regulators have long been conscious of the pollution generated by motor vehicles. Consequently, there have been numerous legislative guidelines designed to restrain harmful releases from these sources (Jacobson et al, 2013). However, aircraft and aviation emissions have only lately become the focus of regulatory investigation, although little has been accomplished to reduce and manage emissions produced by aviation industry. While there has been some concerns to curb the substantial carbon dioxide emissions generated by airlines, there has been comparatively little effort to regulate or restrict some of the more harmful air pollutants produced by jet engines. This insufficiency in regulating air pollution from airlines can be traced back to the manner in which air pollution is controlled in the United States through the Clean Air Act. The existing Federal law pre-empts all federal, state, and local authorities except the Federal Aviation Administration from developing measures to reduce harmful emissions from airlines due to possible interstate and global commerce conflicts that might come from other decentralized guidelines.
The United States Clean Air Act (CAA) lays vital guidelines that require the Environmental Protection Agency (EPA) to develop and impose the regulations to guard the general public from unwarranted exposure to airborne pollutants that are known to be harmful to and hazardous to human health (Caiazzo et al, 2013).Not only are airlines some of the biggest polluters of environmental air pollution in the United States, but they also have comprehensively rich data resulting from daily recording of operations, describing for each flight the span of time spent taxiing to and from the entrance before take-off and even after landing.
Effects of Air pollution
Numerous studies have associated air pollution with a number of problems. These include:
Respiratory and heart problems: The pollutants in the atmosphere are known to create numerous respiratory and heart conditions along with other diseases such as cancer,chronic obstructive pulmonary disease (COPD), and other threats to the human body. These harmful particles can get embedded deep inside the lungs and then even enter the bloodstream causing health complications. Children living in areas exposed to intensive air pollution, such as airports are said to commonly show characteristics of respiratory diseases such as pneumonia and asthma. A new Massachusetts research has shown that children living in areas adjacent to Logan International Airport in Boston were up to four times more probable to show signs of asthma than those living in areas further away, even after considering socioeconomic features and other factors (Graham, Hall & Morales, 2014). In addition, adults living in areas near the airport were almost twice more likely to have COPD than their peer living in communities farther away from the airport (Graham, Hall & Morales, 2014).
Global warming: Another catastrophic effect of air pollution is global warming. Emissions of carbon dioxide from a burning jet fuel causes greenhouse effect causing increased global temperatures. Though carbon dioxide is produced by living things as they breathe, emissions of carbon dioxide from airlines is thought to distort the natural balance, causing havoc in the atmosphere. The sustainment of ecosystem and all things living is as a result of combination of gases that collectively constitute the air in the atmosphere; the imbalance resulting from increase or decrease of the proportions of these gases can be destructive to the atmospheric conditions.Carbon dioxide is mainly considered to be a pollutant when associated with motor vehicle, airlines, diesel power plants, and other human activities that result to burning of fossil oils such as gasoline and natural gas (Stohl et al, 2003). Carbon dioxide is denser than air, and therefore excessive production of carbon dioxide will cause increased percentage of carbon dioxide in the atmosphere trapping heat within the earth surface. With increased temperatures globally, rise in sea levels and increased melting of icebergs and snow from polar regions, dislocation and loss of habitat have already signalled an imminent disaster if appropriate actions for protection and stabilization are not undertaken soon. Global warming, a direct consequence of the augmented imbalance of gases in the atmosphere has come to be known as the main threat and challenge that the modern world has to counter in the bid for survival.
Acid Rain: Another harmful effect of air pollution is acid rain. When harmful chemicals and gases such as nitrogen oxides (NOx) and sulfur oxides (SOx) are released into the atmosphere when fossil fuel burns, they increase acidity in the atmosphere (Jacobson et al, 2013). The atmospheric precipitation and the water droplets from rainfall combines with air pollutants in the atmosphere becoming acidic rainfall that falls on the ground causing acidification of the soils and altering with the soil pH. Acid rainfall causes corrosionof iron sheets and alters agricultural production.
Eutrophication: Eutrophication is a condition which results to increased growth of sea algae. This occurs when huge amount of nitrogen available in some air pollutants develops on sea’s surface and causes increased growth of algae that harmfully affect fish, sea plants and animal species. Normally, the green colored algae found on lakes and ponds are due to occurrence of this chemical. The increases growth of algae alters the oxygen balance in the water leading to death of sea animals and plants.
Effect on Wildlife and Plants: Just as humans, wildlife and plants also faces some distressing effects of air pollution. Harmful chemicals present in the air contaminants can force wildlife species to relocate to new habitats. Accumulation of particulate matter on the leaves surface interferes with photosynthesis process and may lead to death of plants. The harmful pollutants deposit over the water surface can alter the diffusion of air in water leading to water animals and plants.
Depletion of Ozone layer: Ozone exists is a vital covering found in the earth’s stratosphere and is usually responsible for absorbing harmful ultraviolet (UV) rays and protecting the earth’s surface from these harmful rays. The presence of chlorofluorocarbons and hydro chlorofluorocarbons emanating from air pollution depletes the Earth’s ozone layer. Scientists have established that increased exposure to harmful ultraviolet rays causes skin and eye related diseases. Ultraviolet rays also have the devastating effect on crops. The Ozone layer is considered a vital covering for the survival of the ecosystems on the Earth surface.
Ways of Reducing Aviation Pollution
As more people seek airline transport, global aviation sectors is expanding and its carbon emissions are expected to triple by the year 2050. Already, airplanes account for 2% t of all human-induced carbon emissions and 12% from the entire transportation industry (Caiazzo et al, 2013). The airlines also discharge pollutants that cause smog and soot cloaking many towns and cities. This calls for abrupt measures to check the growing levels of emissions in airline industry.
Several recent changes in the aviation industry have significantly improved the system efficiency and lowered environmental impact (Ponater et al, 2006). In the past few decades, reliable meteorological information accessible in the cockpit in real time has enabled optimization of flight planning with smaller routing. Yield management equipment has enabled airlines to increase their load factors, which move more travellers on every flight. The hub and spoke system, blended with the increase of low cost point-to-point carriers and a substantial increase in the number and spread of regional airlines, has significantly improved the efficiency of the entire aviation system.
Currently, there are a number of programs and initiatives in progress that is expected to achieve substantial emissions reductions both at airports and within the global aviation system in the subsequent years. First, there are proactiveapproaches underway at the airports meant to lower emissions from ground support machineries and other airport vehicles. Federal Aviation Administration (FAA) established a pilot program, with US Environmental Protection Agency (EPA) and Department of Energy (DOE), to exhibit air quality enhancements with better fuel ground support equipment (Graham, Hall & Morales, 2014). The initiative program is referred to as Inherently Low-Emissions Airport Vehicle (ILEAV) Pilot Program. The new Voluntary Airport Low Emission program extends eligibility for airport low discharge projects under the support of Airport Improvement Program (AIP) along with Passenger Facility Charges (PFC) program.
To reduce discharges from these airport vehicles, airline companies have engaged in voluntary emission reduction initiatives (Graham, Hall & Morales, 2014). For instance, California and Texas have agreements with the main airlines to lower emissions from their ground support machineries. The new arrangementsare expected to reduce harmful emissions by using solar powered and electric equipment andinstead of gasoline and diesel equipment.Generally, the aviation sector is working hard to lower the level of pollutants released, through mechanical improvements to aircraft and jet engine design, working procedures and fuels.
Additionally, many airports have strategically taken initiatives to cut emissions from cars, buses, vans, taxicabs, and other ground support vehicles that operate in and about the airport (Graham, Hall & Morales, 2014). Currently, there are airports using hybrid-electric vehicles to transport aviation staffs and travellers around the airport. In some major airports, police departments within the airports are using compressed natural gas vehicles and aircraft maintenance departments are making use of alternative fuel trucks to move around the airport. Precisely, airport shuttle buses have been improved to make use of compressed natural gas instead of gasoline.Heavy maintenance department are making use of new clean diesel trucks which do produce carbon emissions.
NASA is also making substantial progress toward addressing the menace of air pollution through sophisticated technology. Solar-powered Solar Impulse 2 and battery-powered plane are some of technologies being developed, and they are likely to lower emissions from commercial airlines in the near future. Other technologies such as biofuels, lighter engines modifications, efficient aerodynamic designs, bug-proof coatings, and 3D printing of aircraft parts could significantly boost fuel efficiency, which in turn will reduce air pollution (Graham et al, 2014).
Some vital aspect that should be considered when tackling the issues of airline pollution is operation procedures. Operating procedures have been considered to have both direct and indirect impact on aircraft emissions (Caiazzo et al, 2013). Big airlinesnormally employ standard measures for operating their aircraftsin order to meet the corporation’s goals for safety, devotion to flight timetables, fuel conservation guidelines, labor agreements and regulations, and other factors associated with aviation industry. Normally, standard measures vary depending on aircraft type, airport-specific restrictions, and weather. The application of best practices and alternative procedures offers some vital prospect for cutting emissions.
Some aircraft procedures have impact on the engine-operating regime, which is thought to directly influence the proportions of emissions. Nitrogen dioxide emissions are normally higher during high power operations sessions such as takeoff when combustor temperatures are normally high (Jacobson et al, 2013). Additionally, Hydrocarbon and carbon monoxide emissions are highest during low power operations sessions such as taxiing period when combustor temperatures are low and the aircraft engine is less efficient. Therefore, lowering engine power for a given session like take-off or climb out basically increases the rate of hydrocarbon and carbon monoxide emissions, and lowers the rate of nitrogen oxide emissions, and has little or no impact on carbon dioxide emissions.
Other operating processes have a more elementary effect on engine usage and can significantly reduce all emissions simultaneously. For example, United Airlines developed a new programrecently to lower the average application of its auxiliary power units through the use of ground power whenever possible.
Air pollution from airlines cannot be overlooked. There are severe impacts caused by the airline emission to the aviation staffs, people neighbouring the major airports and to the entire ecosystem as a result of supporting global warming. Current researchers have found some of the worrying particle levelsin areas around the airport. Therefore invoking vitals measures to control and reduce emissions from airlines is paramount. New technologies to better air traffic management will significantly help reduce harmful emissions in and around airports. This should include improved technology in communication, navigation, and surveillance will significantly improve air traffic management efficiency in the terminal zone air space, reduce overcrowding, and accordingly reduce aircraft fuel wastage.They will guarantee more efficient approach routes to accurately keep aircraft on good track. They will also increase the capability of airstrips, reducing arrival layout and making ground operations better.
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