Landing And Take-off Cycle Research Articles

Recent Advances and Implications for Aviation Emission Inventory Compilation Methods

With the rapid development of industrialization and urbanization in China, civil aviation plays an increasingly important role in the transportation industry. However, pollutants and greenhouse gas (GHG) emissions from civil aviation are becoming an increasingly concerning environmental problem. In order to mitigate the resulting environmental pollution, such as air quality deterioration, regional and global climate warming, and declining human health, more and more efforts have been devoted to reducing both pollutants and GHG emissions. Among these efforts, emissions inventories from civil aviation provide a basis for quantifying pollutants and GHG emissions, establishing evaluation standards of environmental impact, and formulating management policies for both air quality improvement and climate change mitigation. In this paper, we reviewed both compilation approaches and data collection methods for civil aviation emissions inventories, introduced several typical calculation methods for aviation emissions inventories, and analyzed specific cases of actual application based on typical methods of inventory compilation. We also described in detail the activity level and emission index calculation methods of several pollutants and greenhouse gases. Furthermore, based on the above research methods, four typical application cases were investigated, including a specific airport, the landing and takeoff (LTO) cycle of a nation, the entire period with the LTO cycle and the climb–cruise–descent (CCD) phase of a country, and global emissions inventories from civil aviation. The results suggest that, in addition to quantifying the emissions of both pollutants and GHG produced by civil aviation, the selection of inventory compilation methods is likely to be important for improving aviation emission inventory accuracy and for further reducing the environmental, economic, and health impacts resulting from aviation emissions. Moreover, this paper can also provide a reference and theoretical basis for the development of aviation emission inventory compilation methods in the future.

Comprehensive assessment of air pollutant and noise emissions at airports across different altitudes

<p>We utilized the International Civil Aviation Organization (ICAO) standard emission model, refined with adjustments for fuel flow, LTO cycle work mode time, and emission indices, to investigate the environmental footprint of airports at different altitudes. Airports categorized as high (above 5000 $ \mathrm{f}\mathrm{t} $), medium (1500–5000 $ \mathrm{f}\mathrm{t} $), and low (below 1500 $ \mathrm{f}\mathrm{t} $) altitudes were selected to provide a comprehensive representation of the altitude spectrum. The analysis was anchored over the period spanning 2016 to 2017. Emission inventories for air pollutants and noise were computed for these airports, focusing on the LTO (Landing and Take-Off) cycle. Our findings indicated that high altitude airports exhibit the highest $ {\mathrm{N}\mathrm{O}}_{\mathrm{x}} $ emissions, reaching 406.4 $ \mathrm{t} $, whereas low altitude airports record the highest noise levels at 73.1 $ \mathrm{d}\mathrm{B} $. Significant disparities in emission profiles were observed across different phases of the LTO cycle at airports of varying altitudes. Notably, during the climb phase, the types and proportion of $ {\mathrm{N}\mathrm{O}}_{\mathrm{x}} $ emissions at high altitude airports were as high as 71.8%, contrasting with the 45.6% at low altitude airports. Additionally, emissions of gaseous pollutants from major aircrafts, exemplified by the A320 model, escalated with altitude. Specifically, $ {\mathrm{N}\mathrm{O}}_{\mathrm{x}} $ emissions increased from 10.55 $ \mathrm{k}\mathrm{g}/\mathrm{c}\mathrm{y}\mathrm{c}\mathrm{l}\mathrm{e} $ at low altitude to 20.48 $ \mathrm{k}\mathrm{g}/\mathrm{c}\mathrm{y}\mathrm{c}\mathrm{l}\mathrm{e} $ at high altitude, and $ \mathrm{C}\mathrm{O} $ emissions from 10.88 $ \mathrm{k}\mathrm{g}/\mathrm{c}\mathrm{y}\mathrm{c}\mathrm{l}\mathrm{e} $ to 22.89 $ \mathrm{k}\mathrm{g}/\mathrm{c}\mathrm{y}\mathrm{c}\mathrm{l}\mathrm{e} $. A robust correlation between $ {\mathrm{N}\mathrm{O}}_{\mathrm{x}} $ emissions and $ {L}_{den} $ was identified among airports at different altitudes, with correlation coefficients of 0.96 for low altitude, 0.97 for medium altitude, and 0.93 for high altitude airports. This study delineates the distinct characteristics of air pollutant and noise emissions from airports across altitudes, offering novel insights for the environmental assessment of airport operations.</p>

Ispersion model and impact assessment of Landing and Take-Off (LTO) activity at New Yogyakarta International Airport using aermod

Pollutant dispersion modeling in around Yogyakarta International Airport wasconducted using AERMOD software. There is a strong positive correlation between the number of aircraft and land transportation and the number of pollutants considered. The ambient air quality at the study site for all pollutants originating from the landing and take-off (LTO) cycle is still below quality standards, but for those sourced from the combination of the LTO cycle and land transport traffic for NO2 pollutants exceed the quality standard, while for CO and hydrocarbon pollutants it is still below quality standards.

Impact of the COVID-19 pandemic on air pollution from jet engines at airports in central eastern China.

Aircraft engine emissions (AEEs) generated during landing and takeoff (LTO) cycles are important air pollutant sources that directly impact the air quality at airports. Although the COVID-19 pandemic triggered an unprecedented collapse in the civil aviation industry, it also relieved some environmental pressure on airports. To quantify the impact of COVID-19 on AEEs, the amounts of three typical air pollutants (i.e., HC, CO, and NOx) from LTO cycles at airports in central eastern China were estimated before and after the pandemic. The study also explored the temporal variation and the spatial autocorrelation of both the emission quantity and the emission intensity, as well as their spatial associations with other socioeconomic factors. The results illustrated that the spatiotemporal distribution pattern of AEEs was significantly influenced by the policies implemented and the severity of COVID-19. The variations of AEEs at airports with similar characteristics and functional positions generally followed similar patterns. The results also showed that the studied air pollutants present positive spatial autocorrelation, and a positive spatial dependence was found between the AEEs and other external socioeconomic factors. Based on the findings, some possible policy directions for building a more sustainable and environment-friendly airport group in the post-pandemic era were proposed. This study provides practical guidance on continuous monitoring of the AEEs from LTO cycles and studying the impact of COVID-19 on the airport environment for other regions or countries.

Environmental and enviroeconomic impacts of COVID-19 pandemic on commercial flights

PurposeThe purpose of this study is to determine and compare the total and per passenger HC, CO, NOx and CO2 emissions from aircraft landing and takeoff (LTO) cycle before and during the COVID-19 pandemic. In addition, it is aimed to determine the global warming potential (GWP), environmental impacts (EIs) and enviroeconomic cost (eco-cost) of these emissions in total and per passenger.Design/methodology/approachAnalyses were carried out with the help of the International Civil Aviation Organization’s Engine Emission Databank, using real flight data recorded by the airport authority.FindingsDuring the COVID-19 pandemic, total pollutant emissions (HC, CO, NOx and CO2) decreased between 23.7% and 30.8% compared with the pre-pandemic period. In addition, per passenger pollutant emissions increased during the pandemic. Compared with the pre-pandemic period, GWP, EI and eco-cost values decreased by 24.1%, 23.89% and 23.93%, respectively, in the pandemic. However, the per passenger GWP, EI and eco-cost values increased by about 10% compared with the pre-pandemic period.Practical implicationsThis study reveals the effects of COVID-19 in terms of EIs and environmental costs caused by aircraft in the LTO cycle.Originality/valueThe originality of this study is to calculate the pollutant emissions caused by aircraft in the LTO cycle with real flight data and to reveal the effects of the COVID-19 pandemic. The novelty of this study is the determination and comparison of total and per passenger pollutant emissions, GWP, EI and eco-cost before and during the pandemic.

Assessment of predicted aircraft engine non-volatile particulate matter emissions at Hangzhou Xiaoshan International Airport using an integrated method

ABSTRACT Assessing the aircraft engine nonvolatile particulate matter (nvPM) emissions during landing and take-off (LTO) cycles is significant for airport air quality management. However, presently few prior studies have examined aircraft engine nvPM emissions on a daily basis for optimizing flight operations at airports. Therefore, based on the latest first-order approximation method of engine nvPM emissions, we introduce the engine emission data and aircraft flight data to establish an integrated method for estimating daily aircraft engine nvPM emissions at airports. This method can be applied to obtain different engine nvPM mass and number emissions in each phase of the LTO cycle, and therefore the total nvPM mass and number emissions in different time periods can be estimated for the analysis of the sources and trends of daily aircraft engine nvPM emissions during LTO cycles at Hangzhou Xiaoshan International Airport. Results show that the highest aircraft engine nvPM mass and number emissions are generally predicted to occur in the climb and taxi/ground idle phase, respectively. The proportion of total engine nvPM mass and number emissions in each phase of the LTO cycle could also be estimated, specifically the take-off phase (21% & 6%), climb phase (52% &15%), approach phase (8% & 27%), and taxi/ground idle phase (19% & 52%). In addition, the trends of hourly engine nvPM mass and number emissions during LTO cycles within a day are similar, but the predicted highest total hourly engine nvPM mass and number emissions occur in different time periods (7:00–8:00 a.m. & 11:00–12:00 a.m.) at the airport, and the total hourly engine nvPM mass and number emissions at 6:00 a.m. to 17:00 p.m. are generally higher than those of the rest periods. These results are valuable for optimizing flight operations for mitigating the environmental impact of aircraft engine nvPM emissions. Implications: The integrated method for estimating engine nvPM mass and number emissions in the LTO cycle based on FOA4.0 method reported in this study is effective to assess the sources and trends of daily aircraft engine nvPM emissions during LTO cycles at airports, which is valuable for optimizing flight operations considering the environmental impact of aircraft engine nvPM emissions. When the relevant aircraft flights, engine parameters, and engine nvPM emission databases embedded in the integrated method for any airport are established, the method is feasible to assess the sources and trends of aircraft engine nvPM emissions during LTO cycles at any time period in the airport.

Determination of Environmental Impacts Of Commercial Flights During the Landing and Take-off Cycle

The aim of this study is to determine the hydrocarbon (HC), carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxide (NOx) emissions caused by commercial flights and the global warming potential of these emissions. Environmental effects were calculated for the landing and take-off (LTO) cycles of aircraft and their effects on global warming potential were determined. The environmental impacts of 22 different models of aircraft in the LTO cycle and their impact on global warming potential were calculated. Fuel consumption, HC and CO emissions reached the highest value in the taxi phase. It was determined that NOx emissions reached the highest value in the climb-out phase. It is concluded that HC and CO emissions can be reduced approximately 7% by shortening the taxi time by 2 minutes. It has been calculated that the effect of the climb-out phase on the global warming potential in the LTO cycle is the highest with 40%.

Environmental and enviroeconomic analyses of two different turbofan engine families considering landing and take-off (LTO) cycle and global warming potential (GWP) approach

In this study, environmental and enviroeconomic analyses regarding two different turbofan engine families that are commonly used in commercial aircrafts are carried out at Landing and Take-Off (LTO) cycle involving take-off, climb-out, approach and idle phases. For this aim, HC, CO, NOX and CO2 emissions of family 1 (F1) and family 2 (F2) engines are taken into consideration over the course of LTO cycle based on International Civil Aviation Organization (ICAO) emission database. The average thrust values of these engines are 115.12 kN for F1 engines and 123.77 kN for F2 engines. Global Warming Potential (GWP) and enviroeconomic cost factor (ECF) for the each engine are calculated. Also, to predict GWP and ECF parameters, these metrics are modelled based on by-pass ratio and overall pressure ratio. According to the results of the study, the average GWP value of F1 and F2 engines are obtained as 2256.17 kg_CO2/day_cycle and 1779.02 kg_CO2/day_cycle, respectively. On the other hand, the average enviroeconomic cost factor (ECF) of F1 and F2 engines are computed as 261.71 Euro/day_cycle and 206.36 Euro/day_cycle, respectively. Finally, accuracy of GWP model is achieved with R2 = 0.9956 for F1 engines and R2 = 0.9664 for F2 engines. The relatively low R2 of the model for F2 engines could be attributed to effects of different types of the combustor. It is seemed that the present analysis allows to predict the average environmental effect and economic cost of the aircraft engines in service.

Spatial-Temporal Patterns of Air Pollutant Emissions From Landing and Take-Off Cycles in the Yangtze River Delta of China During the COVID-19 Outbreak.

The global aviation industry has been experiencing catastrophic disruption since the beginning of 2020 due to the unprecedented impact of the COVID-19 pandemic on air traffic. Although the decline in regular commercial air travel has caused tremendous economic loss to aviation stakeholders, it has also led to the reduction in the amount of recorded air pollutants. Most of the aircraft emissions are released during the cruise phase of flight, however they have relatively small impact on humans due to the fact that those emissions are released directly into the upper troposphere and lower stratosphere. Therefore, the scope of this study is to investigate the ground-level aircraft emissions from landing and take-off (LTO) cycles, as they have a greater influence on the ambient environment of the airports in a specific region. In this paper, we study the variation of typical air pollutant concentrations (i.e., HC, CO, and NOx) from the LTO cycles during the outbreak of COVID-19 pandemic in both temporal and spatial scales. These ground-level emissions are estimated for the 22 airports in the Yangtze River Delta, China. The results indicate that the variation pattern of the three air pollutants were significantly influenced by the dramatic onset of the COVID-19 pandemic, as well as the pertinent policies to suppress the spread of the virus. The results also reveal non-uniform distribution of the emission quantified at different airports. It is noticeable that the emission quantity generally declined from the east coast to the central and western part of the research region. Furthermore, discrepancies in the target markets also create disparities in the variation pattern of the emissions at different airports under the context of COVID-19.

METHODICAL ASPECTS OF THE LTO CYCLE USE FOR ENVIRONMENTAL IMPACT ASSESSMENT OF AIR OPERATIONS BASED ON THE WARSAW CHOPIN AIRPORT

The aviation engines homologation process takes place in LTO (Landing and Take-Off) test cycle. Mentioned procedure is good for the approval applications because the test conditions are repeatable and obtained results could be compared between different engines. The authors compared in this article the exhaust emission results obtained in LTO test cycle during selected engine homologation with values obtained in estimations. Two Allied Signal TFE731-2-2B engines with a thrust of 15.6 kN were taken into considerations. The engines are used to propel the popular VLJ (Very Light Jet) aircraft: Dassault Falcon 100. Adopted methodology of emission estimation is very similar to the LTO, because the authors use the emission factors obtained in LTO cycle, specified for selected engines. Also, the duration of take-off, climb-out and approach LTO phases were adopted to the estimations. In the analyzed case, 16 scenarios of taxi phase were selected on the basis of the Warsaw Chopin Airport available runways. Duration of taxi phase in these cases vary between 3.1 to 11.0 minutes which is at least 58% less than in LTO test. Assuming the real taxi times change the exhaust emission results comparing to normal LTO cycle up to about 64%. The proposed methodology could be used for assessing environmental impact of air operations, which can be used to create the reports with more accurate data than with typical LTO times.

Calculation of Aircraft Emissions During Landing and Take-Off (LTO) Cycles at Batumi International Airport, Georgia

In this paper, aircraft emissions (nitrogen oxides, carbon monoxide, and hydrocarbons) were estimated during landing and take-off (LTO) cycles for the year 2018 at Batumi International Airport in Georgia. The calculation model is based on flight data recorded by TAV Airports Holding Corporations in Georgia, including type and number of aircraft, engine type, number of passengers, and emission factors from the International Civil Aviation Organization Engine Exhaust Emission Databank were used for estimating the emissions. The total aircraft emissions during the LTO cycle were assessed as 68.96 t/y (39.78 t/y for NOx, 25.92 t/y for CO, and 3.26 t/y for HC) at Batumi international airport. Domestic flights were accountable for 68% of the total LTO emissions in 2018. The findings displayed that NOx was mainly released during the take-off and climb-out modes, accounting for 27% and 37% of the total emissions. CO and HC emissions were released mostly in taxi mode and responsible for 77% and 70% of total emissions. The assessment demonstrates that a 2-minute reduction in taxi mode results in an approximate 6% reduction in LTO emissions. To predict future emissions, it was evaluated that a 50% increase in LTO cycles would result in an increase of approximately 55-60% in emissions.

Estimation of aircraft emissions at Georgian international airport

Abstract This study is the first which focuses on the estimation of air pollutants including nitrogen oxides, carbon monoxide, and hydrocarbons from aircraft during landing and take-off (LTO) cycles for the year 2018 at Tbilisi International Airport in Georgia. The estimation model is based on flight data recorded by TAV Airports Holding Corporations in Georgia, including type and number of aircraft, engine type, number of passengers, and emission factors from the International Civil Aviation Organization Engine Exhaust Emission Databank were used for calculating the emissions. The total aircraft emissions during the LTO cycle were estimated as 428.78 t/y (247.33 t/y for NOx, 161.21 t/y for CO, and 20.24 t/y for HC) at Tbilisi international airport. International flights were responsible for 99% of the total LTO emissions from all flights in 2018. The results showed that NOx was mainly emitted during the take-off and climb-out modes, accounting for 27% and 37% of the total emissions. CO and HC were mostly produced during the taxi mode, accounting for 77% and 70% of the total emissions. The estimation presents that a decrease of 2 min in taxiing time will result in a decrease of approximately 5% in LTO emissions. To forecast future emissions, it was assessed that an increase of 50% in LTO cycles might cause a rise of between 55 and 60% in emissions. This study will help to create aircraft emission inventory in the Caucasus region.

Evaluation of CO2 Emission at Airports from Aircraft Operations within the Landing and Take-Off Cycle

The importance of airport emission inventory is more specific in the local context as it directly affects the local air quality. The specific gap addressed by this research is evaluating the CO2 emission from aircrafts within the landing and take-off (LTO) cycle. Using currently available methodologies for assessing emission within the LTO cycle in the Sri Lankan context has significant limitations, such as unavailability of relevant operational data and the International Civil Aviation Organization (ICAO)-specified “time-in-mode”(TIM) (e.g., take-off, climb-out, idle, and approach) estimates at different phases of the LTO cycle being inconsistent with local conditions. Such industry-wide standards have been found to over or underestimate actual volumes specific to local conditions. In this research, data collected from online flight-tracking services and daily aircraft movement record (DAMR) data maintained by the local air traffic service provider were used to estimate TIM values according to site-specific conditions. Existing literature to some extent addresses the assessment of CO2 emission levels under different phases of flight separately. In this research, a methodology was developed with available data sources to estimate CO2 emission levels under different phases of flight separately within the LTO cycle. The methodology was applied to Bandaranaike International Airport, Sri Lanka. This approach can be applied to similar scenarios in which operational data limitations exist as elaborated in the study.

Dispersion modeling of gaseous and particulate matter emissions from aircraft activity at Chania Airport, Greece

Aircraft emissions from Landing and Take-Off (LTO) cycles at Chania airport (Crete), Greece were estimated for the year 2016 adopting the International Civil Aviation Organization (ICAO) methodology and using daily data from air traffic. The AERMOD Gaussian dispersion model was elaborated to determine the ground-level concentrations of air pollutants emitted from the aircraft engines. Emissions of CO, NOx as NO2, SO2, CO2, PM2.5 mass, and particle number from aircraft engines were evaluated and ground-level concentrations of these pollutants were determined. The aircraft emissions were mainly derived from the ground-level parts of the LTO cycle. The AERMOD model referring to the 1-h average concentrations has revealed that there were 20 exceedances of NO2 concentrations above the value of 200 μg/m3; two more than the regulated threshold described in the European Union Directive 2008/50/EC.. The exceedances were calculated mostly during the summer period which coincides with the touristic period. High number concentrations of particles were also simulated close to the airport with yearly average values close to 10,000 particles per cm3 at the airport area. Contrary, the contribution from aircraft LTO cycles to the ground-level concentration of CO, SO2, and PM2.5 mass was below the air quality threshold values.

Improved estimation of air pollutant emissions from landing and takeoff cycles of civil aircraft in China

Civil aircraft emissions during landing and takeoff (LTO) are important air pollutant sources, but have been given insufficient attention in China. Accurate estimation of these emissions is limited by a lack of important parameters, such as detailed flight information and the dynamic time in climb and approach modes during LTO that are dependent on mixing layer height (MLH). We developed a flight-time/flight-height relationship using real-time height information in Aircraft Meteorological Data Relay data, and then calculated the actual time for each flight in those two modes based on the actual MLH from meteorological observation. Hourly emissions of civil aircraft were then estimated based on the database of each flight. Total emissions of NOx, CO, SO2, HC and PM from LTO cycles of domestic flights in China during 2015 were 37.78 Gg, 30.25 Gg, 12.00 Gg, 2.38 Gg and 0.75 Gg, respectively. Substantial monthly, daily and hourly variations of emissions due to the flight schedule as well as MLH were calculated. Large differences were found between the new estimation and emissions calculated based on traditional method. Compared with the emissions estimated based on default parameter obtained from International Civil Aviation Organization, the average difference of annual emission among airports with new estimation for various pollutants was approximately 30.3% in climb mode and 81.4% in approach mode; compared with the emissions estimated based on the method proposed by China National Guide, the average difference of annual emission among airports were 37.4% (NOx), 8.4% (CO), 73.1% (HC) and 58.1% (PM) during LTO process. The monthly airport-specific emissions per LTO were also proposed. These can provide necessary and meaningful support for the revision of the values in National Guide.

Estimation and dispersion modeling of landing and take-off (LTO) cycle emissions from Atatürk International Airport

Ataturk International Airport (AIA) hosts the most crowded air traffic in Turkey. It is located to the south of the city in an urban area. A new airport is under construction in the north of Istanbul, which is a rural site. All commercial operations of AIA are going to be moved to the new airport after the completion of the construction. Aircraft emissions have adverse impact on ambient air quality, especially at urban sites. In this study, aircraft emissions from LTO cycles were estimated in AIA. NOx, CO, and HC emissions were 4249, 2153, and 181 t year−1, respectively. Taxi phase was responsible for the vast majority of CO and HC emissions. The majority of NOx emissions occurred from climb phase. Valuation of the emissions was estimated according to their unit damage price. The total damage value was 9,420,848 € year−1. NOx contributed more than 99% of the total amount. Dispersion of the pollutants was modeled with EPA’s AERMOD. The calculated NOx and CO concentrations at the closest air quality monitoring station to the airport were compared with the observed results. The contribution of aircraft emissions to NOx and CO concentrations at the station was 5.1 and 2.4%, respectively. The annual limit value of NOx was exceeded in most of the airport area and the residential area to the west of the airport. The highest concentration was 566 μg m−3, which was estimated at the parking/gate area. The maximum daily 8-h mean concentration of CO exceeded the limit value only at the gates and parking area.

The estimation of GHG emission costs in road and air transport sector: case study of Serbia

The paper gives special attention on long distance passenger transport and specific emissions related to different transport modes, particularly road and air transport sector. The goal of this research is creation and selection of appropriate methodology for modelling the cost estimation of GHG emissions in road and air transport sector for Republic of Serbia as well as the application of the methodology regarding to detailed calculation by transport mode and sub modes. Input data for road transport sector refer to the 2013 and include road and traffic conditions on the road network. Input data for air transport sector are related to the 2014 and international airport ‘Nikola Tesla’ Belgrade as the main hub point with the highest recorded number of aircraft operations in the Western Balkan countries. The obtained results reveal that, due to realized transport volume, diesel cars have the largest share of the costs of GreenHouse Gas (GHG) emissions within the passenger long distance road transport. Cost estimates of CO2 emissions in the air transport sector shows that A319 aircraft type have the major share in total costs. The reasons are twofold: first, a high level of Landing and Take-Off (LTO) emission factor for CO2 and second, largest number of LTO cycles.

Air quality impact of a middle size airport within an urban context through EDMS simulation

The air quality impact of an airport due to both ground sources and air traffic emissions within the troposphere boundary layer is a relevant topic at a local scale, especially where the airport is surrounded by urbanized areas. The work analyses the emissions from the Amerigo Vespucci airport in Florence, Italy. The comparison between the present and the future layout of the airport, which is under project, is addressed, providing a possible tool to guide local air pollution prevention strategies within the framework of the strategic transport infrastructures development.The emission scenarios of the present and future airport layouts were estimated with EDMS 5.1.3, the software package issued by FAA (Federal Aviation Administration) which is an US-EPA (Environmental Protection Agency) preferred model for airport emissions evaluation. The total yearly emissions of NOX,CO,SOX,VOCs and PM10 have been assessed, divided into the main phases of the LTO (landing and takeoff) cycle, provided for each aircraft. The results show that the takeoff phase is mainly responsible for NOX,SOX and PM10 contributions.The AERMOD dispersion model was run over one year to evaluate the concentrations of those pollutants, modelled as chemically inert. The maximum concentrations occur close to the gate and the ground movement areas. However, the air quality standards ruled by Directive 50/2008/EU are never reached except for NOX, which shows an overall maximum of the annual average of about 40μg/m3, close to the standard for the vegetation health (50μg/m3).

Experimental and numerical studies of a lean-burn internally-staged combustor

A lean-burn internally-staged combustor for low emissions that can be used in civil aviation gas turbines is introduced in this paper. The main stage is designed and optimized in terms of fuel evaporation ratio, fuel/air pre-mixture uniformity, and particle residence time using commercial computational fluid dynamics (CFD) software. A single-module rectangular combustor is adopted in performance tests including lean ignition, lean blowout, combustion efficiency, emissions, and combustion oscillation using aviation kerosene. Furthermore, nitrogen oxides (NOx) emission is also predicted using CFD simulation to compare with test results. Under normal inlet temperature, this combustor can be ignited easily with normal and negative inlet pressures. The lean blowout fuel/air ratio (LBO FAR) at the idle condition is 0.0049. The fuel split proportions between the pilot and main stages are determined through balancing emissions, combustion efficiency, and combustion oscillation. Within the landing and take-off (LTO) cycle, this combustor enables 42% NOx reduction of the standard set by the 6th Committee on Aviation Environmental Protection (CAEP/6) with high combustion efficiency. The maximum board-band pressure oscillations of inlet air and fuel are below 1% of total pressure during steady-state operations at the LTO cycle specific conditions.

Statistical Approaches for Identifying Air Pollutant Mixtures Associated with Aircraft Departures at Los Angeles International Airport

Aircraft departures emit multiple pollutants common to other near-airport sources, making it challenging to determine relative source contributions. While there may not be unique tracers of aircraft emissions, examination of multipollutant concentration patterns in combination with flight activity can facilitate source attribution. In this study, we examine concentrations of continuously monitored air pollutants measured in 2008 near a departure runway at Los Angeles International Airport (LAX), considering single-pollutant associations with landing and takeoff (LTO) of the aircraft (LTO activity, weighted by LTO cycle fuel burn), as well as multipollutant predictors of binary LTO activity. In the single-pollutant analyses, one-minute average concentrations of carbon monoxide, carbon dioxide, nitrogen oxides, and sulfur dioxide are positively associated with fuel burn-weighted departures on the runway proximate to the monitor, whereas ozone is negatively associated with fuel burn-weighted departures. In analyses in which the flight departure is predicted by pollutant concentrations, carbon dioxide and nitrogen oxides are the best individual predictors, but including all five pollutants greatly increases the power of prediction compared to single-pollutant models. Our results demonstrate that air pollution impacts from aircraft departures can be isolated using time-resolved monitoring data, and that combinations of simultaneously measured pollutants can best identify contributions from flight activity.