2011-comparison of methodologies estimating emissions of aircraft pollutants, environmental impact...

8/3/2019 2011-Comparison of Methodologies Estimating Emissions of Aircraft Pollutants, Environmental Impact Assessment A

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Comparison of methodologies estimating emissions of aircraft pollutants,

environmental impact assessment around airports

Jermanto S. Kurniawan, S. Khardi 1

INRETS-LTE, 25, avenue Franois Mitterrand, 69675 Bron cedex, France, Kampus Baru UI Depok - Indonesia

a b s t r a c ta r t i c l e i n f o

Article history:

Received 18 March 2010

Received in revised form 21 September 2010Accepted 23 September 2010

Available online 16 October 2010

Keywords:

Aircraft

Pollutant emissions

Emission factors

Methods

Assessment

Airtransportationgrowth hasincreased continuouslyover theyears. Therise in airtransport activity hasbeen

accompanied by an increase in the amount of energy used to provide air transportation services. It is also

assumed to increase environmental impacts, in particular pollutant emissions. Traditionally, the environ-

mental impacts of atmospheric emissions from aircraft have been addressed in two separate ways; aircraft

pollutant emissions occurring during the landing and take-off (LTO) phase (local pollutant emissions) which

is the focus of this study, and the non-LTO phase (global/regional pollutant emissions). Aircraft pollutant

emissions are an important source of pollution and directly or indirectly harmfully affect human health,

ecosystems and cultural heritage. There are many methods to asses pollutant emissions used by various

countries. However, using different and separate methodology will cause a variation in results, some lack of

information andthe useof certain methods will require justification and reliability that mustbe demonstrated

and proven. In relation to this issue, this paper presents identification, comparison and reviews of some of the

methodologiesof aircraft pollutant assessment fromthe past,present and future expectations of somestudies

and projects focusing on emissions factors, fuel consumption, and uncertainty. This paper also provides

reliable information on the impacts of aircraft pollutant emissions in short term and long term predictions.

2010 Elsevier Inc. All rights reserved.

Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241

2. Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241

3. The literature review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241

3.1. Pollutant emissions source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241

3.2. Identification of various methods of assessments and measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242

4. Discussions and comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248

5. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251

Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251

Environmental Impact Assessment Review 31 (2011) 240252

Abbreviations: ALAQS, Airport Local Air Quality Study; APU,AuxiliaryPower Unit; CAEP, Committee on AviationEnvironmental Protection; CH4, Methane;CO, Carbon monoxide;

CO2, Carbon dioxide; EEA, European Environment Agency; EI, Emission indices; EIS, Emission Indices Sheets; EMEP, European Monitoring and Evaluation Programme; EPA,

Environmental Protection Agency; FAA, Federal Aviation Administration; GIS, Geographic Information System; H2O, Water vapor; HAPs, Hazardous air pollutants; HC, Hydrocarbon;

ICAO, International Civil Aviation Organization; IFR, Instrument Flight Rules; IPCC, International Panel of Climate Change; ISA, International Standard Atmosphere; LAQ, Local air

quality; LTO, Landing and take-off; MEET, Methodologies for Estimating air pollutant Emissions from Transport; NMVOC, Non-Methane Volatile Organic Compounds; NOx, Nitrogen

oxides; OD, Origin and destination; PM, Particulate matter; SOx, Sulphur oxides; TBEC, Thrust Based Emission Calculator; TIM, Time in Modes; VFR, Visual Flight Rules; VOC, Volatile

Organic Compounds.

Corresponding author. Tel.: +33 4 72 14 26 13; fax: +33 4 72 14 25 20.

E-mail addresses: [email protected](J.S. Kurniawan), [email protected] (S. Khardi).1 Tel.: +33 4 72 14 24 79; fax: +33 4 72 14 25 20.

0195-9255/$ see front matter 2010 Elsevier Inc. All rights reserved.

doi:10.1016/j.eiar.2010.09.001

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1. Introduction

Air transportation growth has increased continuously over the

years. However, the growth has not been uniform and varies from

country to country. The general increase in air transport activity has

been accompanied by a rise in the amount of energy used to provide

air transportation services. Along with the increase in air transport

activity and energy consumption increased environmental impacts

are assumed.Traditionally, the environmental impact of atmospheric emissions

from aircraft has been addressed in two separate ways. On the one

hand, air quality impacts from aviation have been considered by

regulators, airports and aircraft manufacturers, focusing mainly on the

emissions from aircraft occurring during the landing and take-off

phases (LTO cycle) of aircraft operations (local pollutant emissions).

On the other hand, studies on the environmental impact of aircraft

emissions occurring in other flight phases such as climb and cruise

(non-LTO cycle) have focused mainly on their influence on climate

change, stratospheric ozone and UV-radiation (global/regional pol-

lutant emissions).

The environmental impact of air traffic is often mainly associated

with noise nuisance, smoke and gaseous emissions of carbon

monoxide, unburned hydrocarbons, including methane and nitrogen

oxides (NOx include nitrogen oxide and nitrogen dioxide), sulphur

oxides in the vicinity of airports. Particles (such as particulate matter

PM2.5 and PM10) present the most serious adverse health impacts

from aircraft pollutant emissions. These have been controlled by

implementation of standards and certification of aircraft engines. For

this purpose the ICAO has defined referenceemissions LTO cycle, with

specific thrustsettingsand so-calledTime in Modes foreach operating

mode, which reflects all aircraft operations in the boundary layer

below the so-called inversion height (usually at about 1 km) (Olivier,

1991; ICAO, 2007a,b).

Aircraft pollutant emissions have been of concern since the

beginning of commercial aviation. The continuing growth in air traffic

and increasing public awareness have made environmental consid-

erations one of the most critical aspects of commercial aviation. This

means that pollutant emissions from aviation activity are expected togrow and increase by factors 1.6 to 10, depending on the fuel use

scenario (IPCC, 1999; Antoine, 2004; FAA, 2005).

Conscious of this problem, engine manufacturers have developed

low-emission combustors, and made them available as options. These

combustors have been adopted by airlines operating in European

airports with strict pollutant emissions controls, in Sweden and

Switzerland, for example (Antoine, 2004; Celikel et al., 2005a,b).

Over the past several years, the pollutant emission indices have

declined steadily as shown Fig. 1. However, considerably more

progress has been made with HC and CO than NOx (FAA, 2005).

Current emission regulations have focused on local air quality in

the vicinity of airports. ICAO has set an environmental goal to limit

and reduce the effects of aircraft pollutant emissions on local air

quality from aircraft operations (ICAO, 2007a,b).Operations of aircraft are usually divided into two main parts

(EEA/EMEP, 2009):

The LTO cycle defined by ICAO (1993) includes all activities near

the airport that take place below the altitude of 3000 ft (914 m).

This therefore includes taxi-in and out, take-off, climb-out and

approach-landing.

Cruise is defined as all activities that take place at altitude above

3000 ft (914 m). No upper limit altitude is given. Cruise includes

climb from the end of climb-out in the LTO cycle to the cruise

altitude, cruise, and descent from cruise altitudes to the start of

LTO operations of landing.

Method for measurement, prediction and assessment of environ-

mental problems such as aircraft pollutant emissions have been

carried out. The use of certain methods will require justification and

reliability that must be demonstrated and proven. Various methods

have been adopted for the assessment of aircraft pollutant emissions.

The use of different and separate methodologies causes a variation in

results and there is some lack of information as shown in Table 1. This

is because the gaps or differences in data availability, accuracy data

input, and in-certainties in knowledge on the influence of engine

ageing, the operational aircraft configuration, and atmospheric

conditions on the pollutant emissions and their dispersions (Kalivodaand Kudrna, 1997; IPCC, 1999; Sourdine_II, 2005).

In order to provide reliable information on the impacts of aircraft

pollutant emissions, this paper identifies, reviews and compares

various methods of pollutant emissions assessment and evaluates the

reliable methods to use in terms of accuracy, application, capability

and problem of the uncertainty data and model.

2. Objectives

The objectives of this paper are: identification, review and

comparison of various methods assessing aircraft pollutant emissions

and evaluation of the reliable methods to use in terms of accuracy,

application, and capability.

3. The literature review

3.1. Pollutant emissions source

Emissions from aircraft originate from fuel burned in aircraft

engines. Aircraft jet engines produce CO2, H2O,NOx,CO,SOx, unburned

or partially combusted hydrocarbons also known as VOC, particulates

and other trace compounds (FAA, 2005; ICAO, 2007a,b).

A small subset of the VOCs and particulates are considered

hazardous air pollutants (HAPs). Aircraft engine emissions are

roughly composed of about 70% CO2, a little less than 30% H2O, and

less than 1% each of NOx, CO, SOx, VOC, particulates, and other trace

components including HAPs. About 10% of aircraft emissions of all

types, except HC and CO, are produced during airport ground leveloperations and during landing and take-off. The bulk of aircraft

emissions (90%) occur at higher altitudes. For HC and CO, the split is

closerto 30% ground level emissions and 70% at higheraltitudes (FAA,

2005).

Emission from combustion processes CO2 is the product of

complete combustion of hydrocarbon fuels like gasoline, jet fuel,

and diesel. Carbon in fuel combines with oxygen in the air to produce

CO2. Water vapor is the other product of complete combustion as

hydrogen in the fuel combines with oxygen in the air to produce H2O.

Nitrogen oxides are produced when air passes through high

temperature/high pressure combustion and nitrogen and oxygen

present in the air combine to form NOx (FAA, 2005).

Hydrocarbons are emitted due to incomplete fuel combustion by

an engine. Carbon monoxide is formed due to the incompletecombustion of the carbon in the fuel. Sulphur oxides are produced

when small quantities of sulphur, present in essentially all hydrocar-

bon fuels, combine with oxygen from the air during combustion.

Particulates small particles that form as a result of incomplete

combustion, and are small enough to be inhaled. Particulates can be

solid or liquid. Ozone (O3) is not emitted directly into the air but is

formed by the reaction of VOCs and NOx in the presence of heat and

sunlight. Ozone forms readily in the atmosphere and is the primary

constituent of smog. For this reasonit is an important consideration in

the environmental impact of aviation (FAA, 2005; ICAO, 2007a,b).

Compared to other sources, aviation emissions are a relatively

small contributor to air quality concerns both with regard to local air

quality and greenhouse gas emissions. While small, however, aviation

emissions cannot be ignored (FAA, 2005).

241 J.S. Kurniawan, S. Khardi / Environmental Impact Assessment Review 31 (2011) 240252


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Emissions will be dependent on the fuel type, aircraft type, enginetype, engine load and flying altitude. Two types of fuel are used.

Gasoline is used in small piston engine aircraft only. Most aircraft run

on keroseneand the bulk of fuel used for aviation is kerosene (Rypdal,

2009).

In general, two types of engines exist; reciprocating piston engines

and gas turbines (Olivier, 1991; EEA/EMEP, 2009).

3.2. Identification of various methods of assessments and measurements

There have been a fewstudies of aircraft pollutantemissions. Some

of these studies focused on measurement of aircraft pollutant

emissions such as using remote sensing and Fourier transform

infrared (FTIR) emission spectroscopy (Heland and Schafer, 1998;Schafer, 2001; Schafer et al., 2003), visible spectroscopy/miniature

differential absorption spectroscopy (Melamed et al., 2003), ICAO

methodology to calculate the total NOx emissions from aircraft during

Engine Ground Running (Morris and Buttress, 2005), using the

chromatographic analysis to determine carbon species emissions

(Anderson et al., 2006), open path devices to determine real in-use

emission indices of aircraft (Schumann et al., 2007) and the

methodology of on-wing commercial aircraft measurement by

collecting samples from engines using a probe positioned behind

the exhaust nozzle of the aircraft (Agrawal et al., 2008).

Other studies focused on modeling and assessing the local and

regional impact of aircraft pollutant emissions. Moussiopoulos et al.

(1997) quantified the potential impact of emissions from a planned

airport on the Athens basin using an Eulerian dispersion model.Dameris et al. (1998), in a first approach to estimate the sensitiveness

of the atmosphere on aircraft NOx emissions, used the coupled 3-D

dynamic-chemical model ECHAM3/CHEM. Plummera et al. (2001)used regional-scale models to assess the effects of various hydrocar-

bon and NOx emission control strategies on ozone concentrations. Yu

et al. (2004) used the nonparametric regression method to estimate

the average concentration of pollutants such as SO2 and CO as a

function of wind direction and speed based upon recorded data. Pison

and Menut (2004) quantified the impact of aircraft emissions on

ozone concentrations over Paris areas using a mesoscale air quality

model, CHIMERE, with 150 150 km2 resolution and a vertical

extension of 3100 m. Unal et al. (2005) quantified the impact of

aircraft emissionson regional air quality, especially in regards to PM2.5and ozone using a first-order approximation where emission rates are

a function of smoke number (SN) and fuel flow rate for different

engine types in different modes of operation. Gauss et al. (2005) used

a 3-D chemical transport model including comprehensive chemistryschemes for thetroposphere and thestratosphere in order to take into

account all chemical processes relevant for theupper troposphere and

lower stratosphere region (UTLS). Kesgin (2006), estimating aircraft

LTO emissions (HC, CO, NOx and SO2) using MEETand the ICAOEngine

Exhaust Emission Databank. Sidiropoulos et al. (2005) calculated

emission factors for selected airports following the analytical

methodology incorporated in the EMEP/CORINAIR2 Atmospheric

Emission Inventory guidebook and the ICAO Engine Exhaust Emission

Databank. Graver and Frey (2009) created an airliner emissions

inventory for RaleighDurham International Airport, based on

Environmental Protection Agency and Tier 2 methodology of

International Panel of Climate Change. This methodology is also

described in EEA/EMEP Air Pollutant Emission Inventory Guidebook.

Wayson et al. (2009) used the First Order Approximation (FOA) 3.0methodology to estimate PM emissions from certified commercial

aircraft engines within the vicinity of airports. FOA3.0 provides a

greater confidence in the estimation of PM from certified commercial

aircraft at airports. This method is developed by Committee on

Aviation Environmental Protection.

Some methodologies of assessment have been used by some

studies to estimate aircraft pollutant emissions such as ICAO, EPA,

EEA/EMEP, MEET, ALAQS and SOURDINE II methodology, thus this

paper will describe and compare those methods to understand which

method provides a reliable assessment for estimating aircraft

pollutant emissions at the airport.

2

Now known as the EMEP/EEA Air Pollutant Emission Inventory Guidebook.

Fig. 1. Local air quality pollutants have declined steadily over the past several years (FAA, 2005).

Table 1

Emission Indices from some references in (g/kg).

References Emission indices (g/kg)

CO2 H2O SO2

ECAC 3100 1240

MEET 3150 1240 1.00

Olivier 3220 1250

Sourdine II 3149 1230 0.84

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ICAO sets emission standards for jet engines. These are the basis of

FAA aircraft engine performance certification standards, established

through EPA regulations.

ICAO has covered three approaches to quantifying aircraft engine

emissions, two in detail and one in overview: simple approach,

advanced approach and sophisticated approach (ICAO, 2007a,b).

a. Simple Approach is the least complicated approach, requires the

minimum amount of data and provides the highest level of

uncertainty often resulting in an over estimation of aircraft

emissions. This approach considers the emission pollutant of

NOx, CO, HC, SO2 and CO2. The formula used for calculating

pollutant emissions does not account for specific engine types,

operational modes or TIM as it assumes that the conditions under

study are the same or similar to the default data being used.

Emission of Species X in kg = Number of LTO cycles

Emission Factor

1

b. Advanced approach reflects an increased level of refinement

regarding aircraft types, emission indices calculations and TIM.

This approach represents a more accurate estimation of aircraft

engine emissions compared to the simple approach and considers

the pollutant emissions of NOx, CO and HC.

Eij = TIMjk 60

FFjk = 1000

EIjk NEj 2

where:

Eij Total emissions of pollutant i (e.g. NOx, CO, orHC), ingrams,

produced by aircraft type j for one LTO cycle.

EIjk the emission indices for pollutant i (e.g. NOx, CO, or HC), in

grams per pollutant per kilogram of fuel (g/kg of fuel), in

mode k (e.g. takeoff, climb out, idle and approach) for each

engine used on aircraft type j.

FFjk Fuel flow for mode k (e.g. takeoff, climb out, idle and

approach), in kilograms per second (kg/s), for each engine

used on aircraft type j.

TIMjk Time-in-mode for mode k (e.g. idle, approach, climb out,

and takeoff), in minutes, for aircraft type j.

NEj Number of engines used on aircraft type j.

c. Sophisticated approach is provided in overview, will be further

developed in CAEP/83 and is expected to best reflect actual aircraft

emissions. Use of this approach requires a greater knowledge of

aircraft and engine operations and the use of propriety data or

models that are not normally available in the public domain. The

actual and refined data required for the analysis is obtained from

real-time measurements under this approach. The data and

information typically required for computing aircraft engine

emissions using the sophisticated approach are listed as follows:

Times-in-mode measurements for different aircraft/engine

typesunder different load, route and meteorological conditions.

Reverse thrust deployment measurements for different aircraft/

engine types under different meteorological conditions.

Airport meteorological conditions, where modeling of aircraft/

engine performance accounts for variation in meteorological

conditions.

Frequency and type of engine test runs.

Frequency of operational aircraft towing.

Airport infrastructure and constraints (e.g. runway length).

Typical or actual throttle settings used during reverse thrust

operation.

Actual aircraft/engine configuration data.

Actual fuel flow data.

Actual idle engine-type idle speeds.

Typical or actual throttle settings for approach take off and

climb out (e.g. reduced thrust take-off procedures).

Approach and climb profiles.

Frequency of less than all engine taxi operation.Using actual performance and operational data, engine emissions

factors can be calculated using programs such as the Boeing Fuel Flow

Method 2 or the Deutsches Zentrum fr Luft- und Raumfahrt Method

(ICAO, 2007a,b).

Once the actual fleet engine emission factors, times-in-mode and

fuel flows are known, the LTO emissions are calculated using the

Eq. (2) that is used in the advanced approach, where:

Eij Total emissions of pollutant i (e.g. NOx, CO, orHC), ingrams,

produced by aircraft type j for one LTO cycle.

EIjk Performance based emission index for pollutant i (e.g. NOx,

CO, or HC), in grams per pollutant per kilogram of fuel (g/kg

of fuel), in mode k (e.g. takeoff, climb out, idle and

approach) for each engine used on aircraft type j.FFjk Fuel flow for mode k (e.g. takeoff, climb out, idle and

approach), in kilograms per second (kg/s), for each engine

used on aircraft type j.

TIMjk Time-in-mode based on aircraft operational performance

for mode k (e.g. idle, approach, climb out, and takeoff), in

minutes, for aircraft type j.

NEj Number of engines used on aircraft type j.

An example of pollutant emissions calculation in LTO cycle is

shown in Table 2: aircraft type: B737 400; engine type: JT8D-17 (Pratt

and Whitney); TIM fuel flow and emission indices are based on ICAO

Engine Exhaust Emission Databank (ICAO, 2009). This calculation uses

an advanced approach methodology.

EPA recommended emissions calculation methodology for a givenairport in any given year and can be summarized in six steps:

1) Determine the mixing height to be used to define a LTO cycle.

2) Determine airport activity in terms of the number of LTOs.

3) Define the fleet make-up at the airport.

4) Select emission factors.

5) Estimate TIM.

6) Calculate emissions based on the airport activity, TIM, and aircraft

emission factors.

Steps two throughfive arerepeatedfor each type of aircraft using a

given airport. This methodology is essentially the same as that used in

theFAAAircraft Engine EmissionsDatabase(FAEED) model(EPA, 1999).

For Time in Mode calculations, the duration of the approach and

climb-out modes depends largely on the mixing height selected. EPAguidance provides approach and climb-out times for a default mixing

height of 3000 ft, and a procedure for adjusting these times for

different mixing heights. The adjustments are calculated using the

equation below (EPA, 1999):

Climb-out:

TIMadj = TIMadj MixingHeight500

3000500

!3

Approach:

TIMadj = TIMadj MixingHeight

3000 ! 4

3 The eighth meeting of the CAEP assists the Council in formulating new policies and

adopting new Standards on aircraft noise and aircraft engine emissions. CAEP has held

seven meetings, usually at three-year intervals.

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For emissions calculation, the total emissions per LTO cycle for a

given aircraft type is calculated using the following equation:

Eij = TIMjk FFjk = 1000 EFijk NEj 5

where: TIMjk = Time in Mode k (min) for aircraft type j; FFjk = fuel

flow for mode k (lb/min or kg/min) for each engine used on aircraft

type j;EFijk = weighted-average emission factor for pollutant i, in

pounds of pollutant per 1000 lb of fuel (kilograms pollutant per

1000 kg fuel), for aircraft type j in operating mode k; NEj = number of

engines on aircraft type j.

The weighted-average emission factor per 1000 lb of fuel is

calculated as follows

EFijk =NMjm = 1 Xmj EFimk

6

where: EFimk = the emission factor for pollutant i, in pounds of

pollutant per 1000 lb of fuel (or kilograms pollutantper 1000 kg fuel),

for engine model m and operatingmode k; Xmj = the fractionof aircraft

typej with engine model m; NMj = the total numberof enginemodels

associated with aircraft type j. Note that, for a given aircraft type j, the

sum ofXmj for all engine models associated with aircraft j is 1.

Once the preceding calculations are performed for each aircraft

type, total emissions for that aircraft type are computed by

multiplying the emissions for one LTO cycle by the number of LTO

cycles at a given location:

Ei = Eij LTOj

7

where Eij=the total emissionsfor pollutant i from aircraft typej; LTOj =

the number of LTOs for aircraft type j.

The total emissions for each aircraft type are summed to yield total

commercial exhaust emissions for the facility as shown in the

following:

ETi =N

j = 1 Eij LTOj

8

where ETi = the total emissions for pollutant i from all aircraft types;Eij = the emissions of pollutant i from aircraft type j; LTOj = the

numberof LTOs foraircrafttypej; and N= thetotal numberof aircraft

types.

An example of pollutant emissions calculation in LTO cycle is

shown in Table 3: aircraft type: B737 400; engine type: JT8D-17 (Pratt

and Whitney); TIM (ICAO Databank); fuel flow and emission indices

are based on Modal Emission Rates Civil Aircraft Engines Air Quality

Procedures for Civilian Airports and Air Forces Bases. Mixing height is

assumed: 3000 ft (in LTO cycle).

EEA/EMEPuses a decision tree (Tier 1, Tier 2 and Tier 3) to select

the methods for estimating the emissions from aviation that are

applicable to all nations (EEA/EMEP, 2009). When estimating aviationemissions the following should be considered:

use as detailed information as is available;

if the source category is a key source, then a Tier 2 or Tier 3 method

must be used for estimating the emissions.

Table 4 summarizes the data required to use the three Tiers in

terms of activity measure and the degree of technology stratification

required for the category 1 Instrument Flight Rules (IFR) flights. It

will often be thecase that theoverall emissionsfor category 2 Visual

Flight Rules (VFR) and category 3 Civil Helicopters flights are

sufficiently small and the statistics available is so poor, that a Tier 1

approach for these portions of aviation is appropriate (EEA/EMEP,

2009).

The Tier 1 and Tier 2 methodologies are both based on LTO dataand fuel used is assumed equal fuel sold. The emission estimation can

be made following either the Tier 1 or Tier 2 methodology.

Forestimating thetotal emissions of CO2, SO2 andheavymetals the

Tier methodology is sufficient, as the emissions of these pollutants are

dependent on the fuel only and not technology (EEA/EMEP, 2009).

The emissions of PM10 or PM2.5 are aircraft and payload

dependent. Therefore, when estimating the total emissions of these

pollutants, it may be appropriate to consider the aircraft activity in

more details, using the Tier 2 methodology. The Tier 3 methodology

may be used to assess an independent estimate of fuel and CO2emissions from domestic air traffic.

The Tier 1 approach for aviation emissions is based on quantity of

fuel consumption data for aviation split by LTO and cruise for

domestic and international flights separately. The method uses asimple approach to estimate the split of fuel use between cruise and

Table 2

Total emissions in LTO cycle using ICAO methodology.

Mode TIM Fuel flow per

engine used

Emission indices per mode each

engine (g/kg of fuel)

Fuel (kg) Tot al emissio n (g)

min kg/s NOx CO HC NOx CO HC

Idle/taxi 26 0.147 3.3 31 10.2 229 757 7109 2339

Approach 4 0.354 6.1 8.54 1.96 85 518 726 167

Climb out 2.2 0.997 15.23 1 0.79 132 2004 132 104

Takeoff 0.7 1.245 19.2 0.74 0.69 52 1004 39 36

LTO total emissions

(g) and fuel (kg)

498 4283 8005 2646

Table 3

Total emissions in LTO cycle using EPA methodology.

Mode TIM Fuel flow per

engine used

Emission indices per mode

each engine (kg/1000 kg)

Fuel (kg) Total emission (kg per 1000 kg)

min kg/s NOx CO HC NOx CO HC

Taxi in 7 0.15 3.29 29.56 9.57 61.81 204 1828 592

Taxi out 19 0.15 3.29 29.56 9.57 167.70 552 4962 1607

Approach 4 0.35 6.23 8.13 1.86 84.98 530 692 158

Climb out 2.2 1.00 15.26 1.01 0.75 131.79 2012 133 99

Takeoff 0.7 1.25 19.30 0.75 0.66 52.26 1011 39 35

LTO total emissions (g)

and fuel (kg)

499 4309 7655 2490



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LTO. This approach was labeled the very simple methodology. This

approach considered emission pollutants SO2, CO2, CO, NOx, NMVOC,

CH4, N2O, and PM2.5.

The Tier 1 approach for pollutant emissions calculation uses the

general equation (EEA/EMEP, 2009):

Epollutant = AR fuel consumption EFpollutant 9

where: Epollutant = annual emission of pollutant for each of the

LTO and cruise phases of domestic and international flights;

AR fuel consumption = activity rate by fuel consumption for each of the

flight phases and trip types; EFpollutant = emission factor of pollutant

for the respective flight phase and trip type.

Tier 1 emission factors (EFPollutant and fuel type) assume an

averaged technology for the fleet, and knowledge of the number of

domestic and international LTO cycles for the nation. Default emission

factors and fuel use (jet kerosene and aviation gasoline) are available

in the EEA/EMEP Guidebook 2009 and some of those are shown in

Table 5. Emission factors are given on a representative aircraft basis.

Where statistics are available for fuel use and the number of LTOs

by domestic and international flights, the assumptions on LTO fuelconsumption below can be used to split these data by LTO and cruise

using the following equation:

Total fuel = LTO fuel cruise fuel 10

where:

LTO fuel = number of LTOs fuel consumption per LTO 11

TheTier 2 approach applies if it is possible to obtaininformationon

LTO per aircraft type but there is no information available on cruise

distances. Thelevel of details for this methodology is the aircraft types

used for both domestic and international aviation, together with the

number of LTO carried out by the various aircraft types. This approachconsiders emission pollutants SO2, CO2, CO, NOx, NMVOC, CH4, N2O,

and PM2.5.

The algorithms are the same as for the Tier 1 approach (EEA/EMEP,

2009):

Epollutant = AR fuel consumption; aircraft type EFpollutant; aircraft type 12

where: Epollutant = annual emission of pollutant for each of the

LTO and cruise phases of domestic and international flights;

AR fuel consumption, aircraft type = activity rate by fuel consumption for

each of the flight phases and trip types for each aircraft type;

EFpollutant, aircraft type = emission factor of pollutant forthe respective

flight phase and trip type for each aircraft type.

This methodology is not relevant for technology abatement

approach (EEA/EMEP, 2009).

The Tier 3 methodologies are based on actual flight movement

data, either for Tier 3A origin and destination (OD) data or for Tier 3B

full flight trajectory information. These methodologies are bottom-up,

flight-based, rather than top-down calculation-based on the fuel

consumed.

Tier 3A takes into account cruise emissions for different flight

distances. Hence details on the origin (departure) and destination

(arrival) airports and aircraft type are needed to use this approach, for

both domestic and international flights. In Tier 3A, inventories are

modeled using average fuel consumption and emissions data for the

LTO phase and various cruise phase lengths, for an array ofrepresentative aircraft categories.

The data used in Tier 3A methodology takes into account that the

amount of emissions generated varies between phases of flight. The

methodology also takes into account that fuel burn is related to flight

distance, while recognizing that fuel burn can be comparably higher

on relatively short distances than on longer routes. This is because

aircraft use a higher amount of fuel per distance for the LTO cycle

compared to the cruise phase as shown in Table 5.

Tier 3B methodology is distinguished from Tier 3A by the

calculation of fuel burnt and emissions throughout the full trajectory

of each flight segment using aircraft and engine specific aerodynamic

performance information. To use Tier 3B, sophisticated computer

models are required to address all the equipment, performance and

trajectory variables and calculations for all flights in a given year.Models used for Tier 3B level can generally specify output in terms

of aircraft, engine, airport, region, and global, as well as by latitude,

longitude, altitude and time, for fuel burn and emissions of CO, HC,

CO2, H2O, NOx, and SOx. To be used in preparing annual inventory

submissions, the Tier 3B model must calculate aircraft emissions from

input data that take into account air traffic changes, aircraft

equipment changes, or any input-variable scenario.

The components of Tier 3B models are ideally incorporated so that

they can be readily updated; therefore the models are dynamic and

can remain current with evolving data and methodologies.

EEA/EMEP only described the algorithm of the Tier 3 methodology

related to Tier 3A. As forTier 2, the emission factors arecalculated on a

flight byflight basis using emission factors and the fuel used for all the

components of a flight (LTO cycle) available from the accompanyingspreadsheet (EEA/EMEP Guidebook 2009) for the representative jet

and turboprop aircraft types (EEA/EMEP, 2009).

Table 4

Input data required for the three Tiers of inventory methodology (EEA/EMEP, 2009).

Activity Technology stratification

Tier 1 Fuel sales sub-divided into

domestic and international usage.

Use average fleet mix

(i.e. generic aircraft EFs)

and average factors

for LTO and cruise.

Total LTO numbers for domestic

and international.

Tier 2 Fuel sales sub-divided into domestic

and international use, as for Tier 1.

Use of aircraft specific

LTO EFs and average

EFs for cruise.LTO numbers for domestic andinternational, per aircraft type.

Tier 3 Data for each flight containing

aircraft type and flight distance,

sub-divided into domestic and

international.

Use specific aircraft type

data from the accompanying

spreadsheet to this chapter,

available from http://eea.

europa.eu/emep-eeaguidebook

Table 5

Emission factors and fuel use for the Tier 1 methodology using jet kerosene as fuel ( EEA/EMEP, 2009).

Fuel SO2 CO2 CO NOx NMVOC CH4 N2O PM2.5

Domestic

LTO (kg/LTO)average fleet (B737-400) 825 0.8 2600 11.8 8.3 0.5 0.1 0.1 0.07

Cruise (kg/ton)average fleet (B737-400) 1.0 3150 2.0 10.3 0.1 0 0.1 0.20

International

LTO (kg/LTO)average fleet (short distance, B737-400) 825 0.8 2600 11.8 8.3 0.5 0.1 0.1 0.07

LTO (kg/LTO)average fleet (B767) 1617 1.6 5094 6.1 26.0 0.2 0.0 0.2 0.15

Cruise (kg/ton)average fleet (B767) 1.0 3150 1.1 12.8 0.5 0.0 0.1 0.20

http://eea.europa.eu/emep-eeaguidebookhttp://eea.europa.eu/emep-eeaguidebookhttp://eea.europa.eu/emep-eeaguidebookhttp://eea.europa.eu/emep-eeaguidebook


7/13

The uncertainties of the estimated aircraft pollutant emissions are

closely associated with the emission factors. The use of representative

emission factors in Tier 1 approach maycontribute significantly to the

uncertainty. The uncertainty may lie between 2030% for LTO and 20

45% for the cruise factors. In Tier 2, there is a high uncertainty

associated with the cruise emission factors and Tier 3, the uncertainty

of different LTO factors is approximately 510%. For cruise, the

uncertainties are assumed to be 1540% (EEA/EMEP, 2009).

An example of pollutant emissions calculation in LTO cycle isshown in Table 6: aircraft type: B737 400; engine type: JT8D-17 (Pratt

and Whitney).

All numbers in Table 6 are based on spreadsheet database in EEA/

EMEP emission guidebook 2009.

MEET has a methodology to estimate the air pollutant emissions

for the flight of an aircraft based on the duration of specific

operational states (engine start, taxi-out, take-off, climb, cruise,

descent, landing, taxi-in and ground operations) and the

corresponding specific emission factors. Using typical flight profiles

(for each aircraft type separately), with the common cruising altitude

of the aircraft and the flight distance being the basic parameters, the

total fuel consumption can be estimated.

MEET describes three main classes of air transport that can be

distinguished when analyzing its operational and emission related

characteristics:

flights performed under IFR,

military operational air traffic,

flights performed under VFR.

There are some minor overlaps between the classes. However,

each category has its own typical data set available for traffic

characteristics and engine emissions.

Accuracy of data input is different for the three categories;

however they contribute to total air transport emissions. About 60%

to 80% of emissions originate from IFRflights. Normally IFRflights are

operated as flights controlled by Air Traffic Services (ATS) within

controlled airspace only and generally flights with civil aircraft

(Kalivoda and Kudrna, 1997).Emission indices for IFRflights, i.e. the mass of pollutant produced

per mass of fuel used, are provided for 9 typical operational

conditions, which combine to cover most of an aircraft's operation

during a flight.

Flights performed under VFR generally are not operated as

controlled flights so neither a Flight Plan nor detailed information on

the route flown is available. However, VFRflights represent less than

5% of fuel consumption and pollutant emissions caused by air traffic

are generally emitted at lower altitudes than IFR flights often even

within the planetary boundary layer (Kalivoda and Kudrna, 1997).

The basic formula for one flight (for a specific aircraft/engine

combination, i.e., different engine types for the same machine are

treated as different aircrafts) is:

E =9

j = 1TjFCjEIj 13

This formula is a compilation and reformulation of the basic

approach from Kalivoda and Kudrna (1997) by Keller and Haan

(1998), where

E[g] total emission of air pollutant

j [] indices running over the 9 operational states, i.e., engine start,

taxi-out, take-off, climb, cruise, descent, landing, taxi-in and ground

operations

Tj [s] duration of operational stage j

FCj [kg fuel/s] fuel consumption during operational stage j EIj [g poll./kg fuel] emission indices of pollutant for operational stagej

Emission indices for IFRflights for each aircraft/engine are given in

Emission Indices Sheets (EIS). Calculation has to be carried out for 9

operational states (OS). Input for the calculation using the aircraft

emission indices sheets for a complete mission from airport to airport

has to be:

aircraft type

total distance between the two airports

cruise altitude.

Additional information is needed:

average duration of taxi-out

average duration of taxi-in.

EIS were produced by MEET covering allthe information necessary

for a calculation. NOx, HC and CO emission indices and fuel

consumption are available in EIS. The methodology and data set

provided will enable users to build air traffic emission inventories for

a region (spatial resolution N10 km), to assess the impact of changes

in the number of aircraft movements, and to assess impacts from

changing the distance flown (e.g. reducing time spent in holding

patterns). There are some gaps and uncertainties in knowledge on the

influence of real in-flight ambient environment conditions and

maintenance and ageing of engines, on the emissions as well as on

the actual amount of emissions from starting up aircraft engines,

additional aircraft related ground operations like refueling and

operating APU and turboprop, piston (Kalivoda and Kudrna, 1997).

An example of pollutant emissions calculation in LTO cycle isshown Table 7: aircraft type: B737 400; engine type: JT8D-17 (Pratt

and Whitney); TIM (DUR = duration) and specific fuel consumption

(SFC); fuel and emission indices are based on EIS MEET database,

assumed CRALT: 3000 ft (in LTO cycle).

Fuel and emission indices of NOx in descent and climb out mode

are calculated by using Eqs. (14) and (15), where c1, c2, c3, c4, d1, d2, d3and d4 are the coefficients provided by EIS MEET.

c1 + c2 CRALT + c3 CRALT2

+ c4 CRALT3

14

d1 + d2 CRALT + d3 CRALT2

+ d4 CRALT3

15

Emission Indices of CO and HC in descent mode are calculated by

using Eqs. (16) and (17), where a1, a2, b1 and b2 are the coefficients

provided by EIS MEET.

a1 + a2 lnCRALT 16

b1 + b2 lnCRALT 17

Emission Indices of CO and HC in climb out mode are calculated by

using Eqs. (18) and (19), where a1, a2, b1 and b2 are the coefficients

provided by EIS MEET.

a1 + a2 = CRALT 18

b1 + b2 = CRALT 19

Table 6

Total emission in LTO cycle using EEA/EMEP methodology.

Mode Fuel (kg) NOx (g) HC (g) CO (g)

Taxi out 92 392 161 2763

Takeoff 43 796 2 39

Climb out 113 1927 5 101

Approach Landing 74 620 5 250

Taxi in 92 392 161 2763

LTO total emiss ions (g) and fuel (kg) 413 4127 333 5915



8/13

ALAQS aims to promote best practice methods for airport LAQ

analysis concerning issues such as emissions inventory, dispersion,

and the data required for the calculations, including emission factors,

operational data, and aircraft landing and take-off profiles.ALAQS methodology consists of developing Pan-European emis-

sion inventory methodology with spatial information and future

application of dispersion modeling to this inventory with use of GIS

technologies. The toolset and database to support ALAQS of European

airports are (Celikel et al., 2009):

Pan-European ALAQS central databank for emission factors of

different sources: all related emissions factors for different pollution

sources are defined and aggregated from different sources and

harmonized in Access database. This will provide the opportunity to

change or compare different emissions factors used for the same

type of sources.

Scalable approach for developing emission inventory and dispersion

modeling.

ALAQS-AV GIS application.

Flight operations encompass the entire LTO cycle as defined by the

ICAO. Emissions of each aircraft type are computed by knowing the

emission factors for the aircraft engines at each power setting (or

mode of operation and the time spent in each mode).

The emission factors included in the ALAQS-AV emission inventory

database are CO, HC, NOx, SOx and PM10. SOx and PM10 emission

factors are not included in the ICAO aircraft engine database, so

substitute indicative figures were used instead.

In ALAQS-AV methodology for a specific scenario, an aircraft

movements table is prepared for this specific period. For each

movement: date, time, aircraft type, arrival/departure flag, gate

(stand) and runway are specified. The ALAQS-AV toolset uses the

movements table to calculate hourly emissions at gates, taxiways,queues and runways.

Aircraft exhaust emissions are calculated for the following

operating modes:

Engine start

Taxi-in and taxi-out (TX, 7% thrust)

Queuing (TX, 7% thrust)

Approach (AP, 30% thrust)

Landing roll (AP, 30% thrust)

Take-off roll (TO, 100% thrust)

Climb-out (CL, 85% thrust)

Except for engine start emissions aircraft engine emissions

during a particular operating mode of the LTO cycle are given by the

product of the Time in Mode, the fuel flow rate and the emission

indices for the appropriate engine thrust setting engaged. Data is

extracted from the system database (i.e. aircraft-engine combination,

number of engines etc.). The equation is shown as follows:

ACe = FFmode EFmode T N 20

where ACe = Aircraft total engine emissions, per LTO cycle; FFmode =

Fuel flow rate (kg/s) per engine in mode; EFmode = Emission factor

(kg/kg) per engine in mode; T = Time in Mode (s); N = Number of

engines.

Aircraft pollutant emissions factors included in the ALAQS-AV

database originate from EDMS4 and are similar to the ICAO

methodology. The ALAQS-AV dispersion modeling studies is initially

focused on using the Lagrangian dispersion model that already exists

in LASPORT (LASAT).5

The ALAQS-AV methodology is recommended by Celikel et al.

(2005a,b), because it is based on individual movements (arrivals anddepartures) and better suited for airport use as they allow the precise

4D repartition of the emissions. In addition ALAQS-AV has the

advantage of being a GIS based application, so that inventory and

dispersion results can be presented with other geo-referenced

information.

The Sourdine II projectobjectives were to suggest and evaluate new

innovative procedures for reducing the impact of emissions and

aircraft noise on the ground (Sourdine_II, 2005).

For the emission assessments of the Sourdine II (SII) Noise

Abatement Procedures (NAPs), a specific tool called TBEC has been

developed. This tool calculates aircraft emission levels associated to a

given Integrated Noise Model (INM)-likeflight profile, on the basis of

the ICAO Engine Exhaust Emissions Data Bank.

The TBEC is a Microsoft Access application which has beenspecially developed for Sourdine II in order to calculate aircraft

emissions HC, CO, NOx, SO2, CO2, H2O, VOC, and Total Organic Gases

(TOG) resulting from the different SII procedures. It uses the ICAO

EngineExhaust Emissions Data Bank, which provides,for a large series

of engine types, fuel flow (kg/s) and emission indices (g/kg of fuel) at

four specific engine power settings (from idle to full take-off power).

The overall principle of TBEC consists of calculating (by interpola-

tions) emission levels, based on the actual thrust along the vertical

fixed-point profiles associated to the SII procedures.

4 A tool for calculating and modeling emission dispersion, stand for Emission

Dispersion Modeling System.5 A program system for the calculation of airport-related pollutant emissions and

concentrations in the lower atmosphere, it was developed in 2002 (LASPORT, www.

janicke.de/data/lasport/lasport-2.0.pdf).

Table 7

Total emission in LTO cycle using MEET methodology.

Mode Fuel per

engine used

Emission indices

per mode each engine

(g/kg of fuel)

TIM c1, c2, c3, c4 d1, d2, d3, d4 a1, a2 b1, b2 Total emissions (g)

kg NOx CO HC DUR (s) SFC (kg/s) Coef. fuel Coef. EI NOx Coef. EI CO Coef. EI HC NOx CO HC

Taxi out 141 3.147 33.3 10.6 480 0.2946 445 4709 1499

Taxi in 106 3.149 33.302 10.598 360 0.29461 334 3532 1124

Landing 36 19.152 0.715 0.468 15 2.42267 696 26 17

Descent 6 4.44 19.51 6.29 4.061 3.702 28.74 8.772 28 124 40

4.426E04 3.710E04 6.026 1.881

9.164E08 2.071E07

5.344E12 3.388E13

Climb out 145 17.51 0.52 1.004 90.20 19.38 0.5235 1.006 2544 76 146

8.386E02 6.940E04 1.115 5.412

1.929E06 2.511E08

4.656E11 3.831E13

Takeoff 109 19.151 0.725 0.468 45 2.42289 2088 79 51


and fuel (kg)

544 6136 8546 2877

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9/13

The emission level of pollutant ELseg is expressed as:

ELseg = Tseg EFsegPi +PsegPi

Pi + 1PiEFseg Pi + 1

EFsegPi

!21

EFseg Pi = EIPi FFseg 22

Pseg =CNT

segMax StaticThrust 100 23

where: EFseg(Pi) = the emission flow for the segment associated to

power setting Pi (in g/s); Pi = one of the tabulated engine power

setting for which emission indices are provided in the data bank (7%,

30%, 85% or 100%); EI(Pi) = the emission indices associated to power

setting Pi (in g/kg of fuel); Pseg = the segment-specific power setting

(%); CNTseg = the average corrected net thrust (lb) on the segment,

calculated using the input CNT values at the two end-points of the

segment; MaxStaticThrust= the engine-specific maximum sea level

static thrust, available in the INM database (lb); ELseg = the emission

level of the pollutant produced on the segment (g); Tseg = the

duration (in seconds) of the flight segment. Tseg is calculated using

the distance between the two end-points of the segment, divided by

the average speed of the aircraft on the segment; Pi and Pi+1 are the

two tabulated power setting values bounding Pseg (%).

To calculate emission levels of different pollutants, it is necessary

to have fuelflow information along theflight profiles. It was originally

planned to approximate these by interpolations on input thrust

values, as the ICAO databank provides fuel flow data associated to

specific power settings. However, the ICAO CAEP's Modeling

Working Group (WG2) considered that estimating fuel flow based

on thrust was unsatisfactory without having a greater knowledge of

individual aircraft/engine performance parameters.

The TBEC tool remains a prototype with several limitations.

Further investigations need to be carried out in order to refine and

validate its modeling principles. Emission results produced with such

a tool should therefore be taken with caution and analyzed in a

relative way (i.e. relative variations of emission levels between the SIIprocedures and a baseline/reference procedure).

The limitation of TBEC is that it does not take into account the

variation of the emission indices with altitude due to temperature and

pressure changes. Indeed, the ICAO databank provides emission

indices for International Standard Atmosphere (ISA) conditions; these

are, however, assumed to be valid for altitudes below 3000 ft. Another

limitation is due to the assumption that emission indices vary linearly

with the thrust level, which is obviously not the case in real life.

CO2, SO2 and H2O emission levels are directly proportional to the

calculated fuel burn and are estimated using the following emission

coefficients (Sourdine_II, 2005).

The ARTEMIS Assessment and reliability of transport emission

models and inventory systems combined the experience from

different emission calculation models and other research in order toharmonize the methodology for emissions estimation at the national

and international level.

The project developed a harmonized emission model for all

transport modes, which aims to provide consistent emission esti-

mates at the national, international and regional level. This requires

first of all additional basic research and a better understanding of the

causes of the differences, mainly with respect to emission factors.

The estimation of aircraft pollutant emissions methodology of EEA/

EMEP and MEET are used by ARTEMIS. This project applied existing

knowledge and closed some of the major gaps for updating the

existing emission database (primarily MEET data) for the influence of

maintenance and ageing of engines on emissions, aircraft/engine

combinations not covered in the current database, i.e. turboprops,

new airframes or former Soviet aircraft and allocation of emissions.

The original MEET data is used in a software tool called AvioMEET

based on the data published in the Emission Indices Sheets of MEET.

However, the inventory tool AvioMEET already includes some

improvements:

Aircraft types are added like Boeing B737-400, B737/500/600/700/

800, B747-400, ATR42, ATR72, BAe 146, etc.

Emission Indices were harmonized with ANCAT/EC26 data within

the United Nations Economic Commission for Europe (UNECE)Emission Inventory Guide Book

Fuel consumption and emissions for climb to 3000 ft and final

approach down from 3000 ft necessary to calculate ground related

emissions are added for COST 3197 category

Fuel consumption and emissions for climb to 3000 ft and final

approach down from 3000 ft necessary to calculate ground related

emissions are added for ICAO category.

AvioMEET generated an emission profile for the components CO2,

H2O, SO2, NOx, CO and HC. The minimum input data to generate such

an emission profile is aircraft type, number of aircraft on this mission

and distance of mission in km.

TheAvioMEETinventory tool cannotbe used to estimateemissions

properly according to Kyoto Protocol option 8 (Allocation to the Party

of emissions generated in its national space and 3D methodology).

Only MEET methodology and its emission function can, (Kalivoda and

Bukovnik, 2005).

4. Discussions and comparison

ICAO and EEA/EMEP have three approaches to quantifying aircraft

pollutant emissions. The approaches are simple approach, advanced

approach and sophisticated approach for ICAO and Tier 1, Tier 2 and

Tier 3 for EEA/EMEP. These approaches depend on the level of

accuracy or complexity need.

The simple approach uses the most common type of engine in

operation internationally for the aircraft type. The emissions factor is

provided in terms of kg of each emission species per LTO cycle per

aircraft. These have been calculated based on the representative

engine type for each generic aircraft type and using ICAO TIM, fuel

flows, thrust settings and other basic assumptions. Therefore, there is

high uncertainty for calculating pollutant emissions in this method.

The Tier 1 approach is based on the premise that data on the

quantities of fuel sold for aviation use are available. It also assumes

that the annual quantity of fuel used is the same as that sold. The

information on the country's total number of LTOs needs to be

available, preferably also the destination for international LTOs,

together with general knowledge about the aircraft types. ICAO

databank of Time in Mode is used by this approach and the emissions

factors and fuel flows are provided by EEA/EMEP databank. The

uncertainty may lie between 2030% for LTO factors and 2045%

cruise factors because of the use of the representative emissions

factors as described by EEA/EMEP guidebook.The advanced approach represents a more accurate estimation of

aircraft engine emissions compared to simple approach because it

attempts to account for the specific engine model on the aircraft. The

emissions factor, TIM and fuel flows are based on ICAO databank.

The Tier 2 methodology is a top-down (fuel sold) methodology

that uses statistics on aviation fuel consumption (split by domestic

and international). To split thefuel useby LTOand cruise, detailed LTO

activity and knowledge of aircraft fleet composition are needed to

provide a more accurate estimation. Fuel flows and emissions factors

are based on EEA/EMEP databank and TIM is based on ICAO databank.

6 Working Group of Abatement of Nuisances caused by Air Transport.7 Coordination research activities of estimation of pollutant emissions from

transportation as well as fuel consumption.

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10/13

The sophisticated approach has a greater level of accuracy; the

actual and refined data required for the analysis is obtained from real-

time measurements. These data and information characterize the

actual fleet composition in terms of aircraft types and engine

combinations, TIM, thrust levels, fuel flows, and possibly combustor

operating conditions for all phases of ground-based and take-off

operations. This approach is almost similar to Tier 3 methodology. The

Tier 3 methodologies are based on actualflight movement data, either

for Tier 3A OD data or for Tier 3B full flight trajectory information.

Hence these methodologies are bottom-up, flight-based, rather than

top-down calculation-based on the fuel consumed. Similar to Tier 1

and Tier 2, fuel flows and emissions factors are based on EEA/EMEP

databank and TIM is based on ICAO databank. EEA/EMEP estimatesthat uncertainty of different LTO factors is approximately 510% and

1540% for cruise.

EPA emission calculation is almost similar to the ICAO methodol-

ogy. The difference is in the emission factors calculation, EPA used the

emission factors which is based on the weighted-average emission

factors that represents the average emission factors per LTO cycle for

all engine models used on a particular type of aircraft. Total emissions

for each aircraft type are computed by multiplying the emissions for

one LTO cycle by the number of LTO cycles then summed to yield total

commercial exhaust emissions. TIM calculation from ICAO databank is

adjusted by calculating duration mixing height of climb out and

approach.

ALAQS, MEET and SOURDINE II use almost the same method

created by the ICAO. ALAQS describes flight operations encompassingthe entire LTO cycle as defined by the ICAO. Emissions of each aircraft

type are computed by knowing the emission factors for the aircraft's

specific engines at each power setting or mode of operation and the

time spent in each mode. In ALAQS methodology for a specific

scenario, an aircraft movements table is prepared for this specific

period. For each movement: date, time, aircraft type, arrival/departure

flag, gate (stand) and runway are specified. ALAQS has a toolset to

calculate hourly emissions at gates, taxiways, queues and runways.

The advantage of using ALAQS is that ALAQS methodology can be

developed with spatial information and future application of

dispersion modeling to this inventory with use of GIS technologies.

However, ALAQS is used only for calculating Total engine emissions in

LTO cycle definedby the ICAO. Andthereare some uncertainties about

the accuracy or the consistency of the data used. For example foremission inventories it is important to gather all the necessary

information about the pollution sources, their operations and

appropriate emission factors.

Whilst MEET uses emission factors based on engine certification

data in the ICAO Engine Exhaust Emission Databank, it contains data

sets of thrust (engine performance), fuel flow and emissions of

components CO, NOx and HC which apply to four different power

settings andalso based on EIS. The methodology and data setprovided

will enable users to build air traffic emission inventories for a region

(spatial resolutionN10 km), to assess the impact of changes in the

number of aircraft movements, and to assess impacts from changing

the distance flown. The advantage of using MEET methodology is that

MEET can be used for calculated air traffic emissions not only locally

but also regionally. The MEET methodology is also used by Kesgin and

ARTEMIS.

Sourdine II has innovative procedures to assess emission fromaircraft using a specific tool called TBEC. The overall calculation

principle consists of estimating the fuel burn and emission level

produced by each segment and summing them (over the flight

profile) to obtain the total fuel burn and emission of each pollutant.

However, this method is similar to the ICAO methodology. The

limitation of TBEC is that it does not take into account the variation of

the emission indices with altitude due to temperature and pressure

changes.

The pollutant emissions of NOx, CO and HC have been considered

by all methodologies. However, only EEA/EMEP Tier 3 methodology

has considered all pollutant emissions. ICAO considers the pollutant

emissions of NOx, CO, HC, SO2, CO2 and SOx. Whilst EEA/EMEP

considers pollutant emissions of CO, NOx, NMVOC, CH4, N2O, PM2.5,

CO2, SO2, PM10 and pollutant emissions of VOC, NOx, CO and SO2considered by EPA.

Since the methodology of ALAQS and Sourdine II used ICAO

methodology, these methodologies do not take into account the

comparison of the example calculation. The summary of comparison

of ICAO, EEA/EMEP, EPA and MEET methodologies calculation is

shown in Tables 813. The comparison of calculation results of those

Table 8

Comparison of results of the methodology calculation in LTO Total Emissions.

ICAO EEA/EMEP EPA MEET Difference of ICAO

EEA/EMEP E PA MEET

Fuel (kg) 498 413 499 544 17% 0.2% 9%


NOx 4283 4127 4309 6136 4% 0.6% 43%

CO 8005 5915 7655 8546 26% 4% 7%

HC 2646 333 2490 2877 87% 6% 9%

Table 9

Comparison of results of fuel calculation per mode.

Fuel (kg) ICAO EEA/EMEP EPA MEET Differences of ICAO

EEA/EM EP EPA MEET

Taxi 229 184 230 248 20% 0.2% 8%

Approach 85 74 85 43 13% 0.2% 50%

Climb out 132 113 132 145 15% 0.2% 10%

Takeoff 52 43 52 109 18% 0.2% 109%

Table 10

Comparison of results of NOx calculation per mode.

NOx (g) I CAO EEA/EMEP EPA MEET D iff er ence s of I CAO

EEA/EMEP EPA MEET

Taxi 757 784 756 779 4% 0.1% 3%

Approach 518 620 530 724 20% 2% 40%

Climb out 2004 1928 2012 2544 4% 0.4% 27%

Takeoff 1004 796 1011 2088 21% 0.7% 108%

Table 11

Comparison of results of CO calculation per mode.

CO (g) ICAO EEA/E ME P EP A MEE T Diff er enc es of ICAO

EEA/EMEP EPA MEET

Taxi 7109 5526 6790 8241 22% 5% 16%Approach 726 250 692 150 66% 5% 80%

Climb out 132 101 133 76 23% 1% 42%

Takeoff 389 39 39 79 0.3% 2% 104%

Table 12

Comparison of results of HC calculation per mode.

HC (g ) ICAO EEA/E ME P EP A MEE T Diff er enc es of ICAO

EEA/EMEP EPA MEET

Taxi 2339 321 2199 2623 86% 6% 12%

Approach 167 5 158 57 97% 5% 66%

Climb out 104 5 99 146 95% 5% 40%

Takeoff 36 2 35 51 96% 4% 41%



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methodologies in Table 8 hasshownthat there aresome differences in

results of fuel consumption and pollutant emissions. A fuel consump-

tion and pollutant emissionof EPA's calculation in LTO Total emissions

has almost the same results compared to ICAO calculation of about

0.2% of fuel flow, 0.6% of NOx, 4% of CO and 6% of HC. Also in MEET

methodology, it hasalmost thesame resultin CO andHC calculation of

about 7% and 9% differences of ICAO. However, there is a bigdifference

of calculation in HC between EEA/EMEP and ICAO of about 87%. This is

because of high uncertainty for LTO cycles in EEA/EMEP methodology.The differences are also shown per mode methodology calculation.

Tables 912 show the comparison results of the methodology

calculation per mode aircraft movement. The MEET methodology

has big differences in results compared to the ICAO of about more

than 100% or over two times of fuel consumption, NOx, and CO in

takeoff mode. However, in total LTO cycle, MEET does not have big

differences in results compared to ICAO. EPA methodology has almost

the same results compared to the ICAO methodology between 0.1%

and 6% in each mode. The difference is only time use in taxi mode,

EPA uses Taxi-in and Taxi-out mode Time and ICAO uses Idle Time

for taxi.

5. Conclusion

It has been shown that a variety of different methodologies has

been and is being used for assessment of aircraft pollutant emissions

both historically and around the world. The use of different

methodologies causes a variation in results of pollutant emissions in

LTO cycle.

Emission factor for aircraft pollutants assessment is commonly

based on the ICAO engine exhaust emission database that contains

data sets of thrust (engine performance), fuel flow and component

emissions.

For various organizations in the EU and the United States, the

fundamental approaches of analysis and management or control of

aircraft pollutant emissions are similar. They used the methodology to

calculate pollutant emissions by using the LTO cycle method provided

by ICAO.Each methodology has advantages and disadvantages to the

method. To choose which is the best method to be used to calculate

the pollutant emissions from aircraft precisely is difficult to decide

and needs to be proven.

This paper has reviewed the main significant methodologies for

assessing the aircraft pollutant emissions and compared those

methodologies. Since ICAO methodology has been used by some

organizations and projects, therefore this methodology is the most

reliable to be used to asses pollutant emissions in LTO cycle. The

example calculation has shown that ICAO methodology is almost the

same as EPA methodology. However, if we need to assess impacts

from changing the distanceflown, impact of changes in the number of

aircraft movement, calculating air traffic emissions locally and

regionally, then MEET methodology can be used for estimatingaircraft pollutant emissions. Although this methodology still needs

some improvement because there are some gaps and uncertainties in

the results of calculation of aircraft pollutant emissions of about two

times compared to ICAO calculation.

However, if the dispersion model is to be considered, then the

ALAQS methodology is more reliable to use.

Acknowledgements

This work is performed in the framework of the cooperation

between University of Indonesia (Indonesia), INRETS (France) and

Ministry of Transportation (Indonesia). The authors wish to thank the

above contributors for their support.

References

Agrawal H, Sawant AA, Jansen K, Wayne Miller J, Cocker III DR. Characterization ofchemical and particulate emissions from aircraft engines. Atmos Environ 2008;42:438092.

Anderson B, Chen G, Blake D. Hydrocarbon emissions from a modern commercialairliner. Atmos Environ 2006;40:360112.

Antoine NE. Aircraft Optimization for Minimal Environmental Impact [dissertation].StanfordUniversity; 2004. [Cited 2009 December]. Available from: http://scholar.google.fr/scholar?q=Antoine+N.+Aircraft+Optimization+for+Minimal+Environmental+Impact&hl=fr&as_sdt=0&as_vis=1&oi=scholart.

Celikel A, Duchene N, Fuller I, Fleuti E, Hofmann P. Airport Local Air Quality Modeling:Zurich Airport Emission Inventory Using Three Methodologies. [Cited 2009October]. Available from:http://www.eurocontrol.int/eec/gallery/content/public/document/eec/conference/paper/2005/007_Zurich_Airport_emissions.pdf2005.

Celikel A, Fuller I, Silue M, Peeters S, Duchene N. Airport Local Air Quality Studies(ALAQS). Concept Document Issue 2.1. EEC/SEE/2005/003. 2006. Sponsored byEurocontrol EATM.

Celikel A, Peeters S, Silue M. Airport Local Air Quality Studies (ALAQS). [Cited 2009October]. Available from:http://www.isa-software.com/Alaqsstudy.

Dameris M, Grewe V, Kohler I, Sausen P, Bruehl C, Grooss J, et al. Impact of aircraft NOxemissions on tropospheric and stratospheric ozone. Part II: 3-D model results.Atmos Environ 1998;32:318599.

EEA/EMEP. Emission Inventory Guidebook; 2009.EPA. Evaluation of Air Pollutant Emissions from Subsonic Commercial Jet Aircraft; 1999

Apr. Report No.: EPA 420-R-99-013.FAA. Aviation & Emissions A Primer. Office Environment and Energy; 2005.GaussM, Isaksen I,LeeD, SovdeO. Impactof aircraftNOx emissionson theatmosphere

tradeoffs to reduce the impact. Atmos Chem Phys Discuss 2005;5:12255311.

GraverB, Frey H.Estimationof AirCarrier Emissionsat Raleigh

DurhamInternationalAirport.Paper 2009-A-486-AWMAProceedings 102nd Annual Conference and Exhibition; 2009Jun 1619. Detroit, Michigan: Air & Waste Management Association; 2009.

Heland J, Schafer K. Determination of major combustion products in aircraft exhaustsFTIR emission spectroscopy. Atmos Environ 1998;32:306772.

ICAO. International Standards and Recommended Practices, Environmental ProtectionAnnex 16. Volume II Aircraft Engine Emissions. second ed. 1993.

ICAO. Airport Local Air Quality Guidance Manual; 2007a.ICAO. Environmental Report; 2007b.ICAO. Engine Exhaust Emissions Databank; 2009.IPCC. Aviation and Global Atmosphere Report; 1999.Kalivoda M, Bukovnik M. Final Report on Air Traffic Emissions. ARTEMIS; 2005 Mar.

Report No.: 2001-002-030.Kalivoda M, Kudrna M. Methodologies for Estimating Emissions from Air Traffic; 1997

Oct. MEET Project, Contract No.: ST-96-SC.204.Keller M, Haan Pd. Intermodal Comparison of Atmospheric Pollutant Emission. INFRAS AG;

1998 Oct. Report No.: B75320-8. Sponsored by the Federal Office for Education andSciences.

Kesgin U. Aircraft emissions at Turkish airports. Energy 2006;31:37284.

LASPORT. A program system for the calculation of airport-related pollutant emissionsand concentrations in the lower atmosphere. [Cited 2010 February]. Availablefrom:http://www.janicke.de/data/lasport/lasport-2.0.pdf.

Melamed M, Solomon S, Daniel J, Langford A, Portmann R, Ryerson T, et al. Measuringreactive nitrogen emissions from point sources using visible spectroscopy fromaircraft. J Environ Monit 2003;5:2934.

Morris K, Buttress J. An estimation of the total NOx emissions resulting from aircraftEngine Ground Running at Heathrow airport. British Airways EnvironmentalAffairs; 2005 Oct. Report No.: ENV/KMM/1127/14.18.

Moussiopoulos N, Sahm P, Karatzas K, Papalexiou S, Karagiannidis A. Assessing theimpact of the new Athens airport to urban air quality with contemporary airpollution models. Atmos Environ 1997;31:1497511.

Olivier JGJ. Inventory of Aircraft Emissions: A Review of Recent Literatur, NationalInstitute for Public Health and the Environment. [Cited 2009 November]. Availablefrom:http://www.rivm.nl/bibliotheek/rapporten/736301008.html.

Pison I, Menut L. Quantification of the impact of aircraft traffic emissions ontropospheric ozone over Paris area. Atmos Environ 2004;38:97183.

Plummera D, McConnell J, NearyL, Kominski J, Benoit R, Drummond J, et al. Assessmentof emissionsdata for theTorontoregion usingaircraft-based measurementsand anair quality model. Atmos Environ 2001;35:645363.

Rypdal K. Aircraft Emission. [Cited 2009 November]. Available from:http://www.ipcc-nggip.iges.or.jp/public/gp/bgp/2_5_Aircraft.pdf.

Schafer K. Non-intrusive measurements of aircraft and rocket exhaust emissions. AirSpace Eur 2001;3:1048.

Schafer K, Jahn C, Sturm P, Lechner B, Bacher M. Aircraft emission measurements byremote sensing methodologies at airports. Atmos Environ 2003;37:526171.

Schumann G, Schafer K, Jahn C, Hoffmann H, Bauerfeind M, Fleuti E, et al. The impact ofNOx, CO and VOC emissions on the air quality of Zurich airport. Atmos Environ2007:10318.

Sidiropoulos C, Ikonomopoulos A, Stratioti A, Tsilingiridis G. Comparison of typical LTOcycle emissions with aircraft engine and airport specific emissions for Greekairports. Proceeding of the 9th International Conference on Environmental Scienceand Technology; 2005. Sep 1-3; Rhodes Island, Greece.

Sourdine_II. Airport Noise and Emission Modeling Methodology; 2005. Contract No.:G4RD-CT-2000-00394.

Unal A, Hu Y, Chang M, Odman M, Russell A. Airport related emissions and impacts onairquality:application to theAtlantainternational airport. Atmos Environ2005;39:

5787

98.

http://scholar.google.fr/scholar?q=Antoine+N.+Aircraft+Optimization+for+Minimal+Environmental+Impact&hl=fr&as_sdt=0&as_vis=1&oi=scholarthttp://scholar.google.fr/scholar?q=Antoine+N.+Aircraft+Optimization+for+Minimal+Environmental+Impact&hl=fr&as_sdt=0&as_vis=1&oi=scholarthttp://scholar.google.fr/scholar?q=Antoine+N.+Aircraft+Optimization+for+Minimal+Environmental+Impact&hl=fr&as_sdt=0&as_vis=1&oi=scholarthttp://scholar.google.fr/scholar?q=Antoine+N.+Aircraft+Optimization+for+Minimal+Environmental+Impact&hl=fr&as_sdt=0&as_vis=1&oi=scholarthttp://www.eurocontrol.int/eec/gallery/content/public/document/eec/conference/paper/2005/007_Zurich_Airport_emissions.pdfhttp://www.eurocontrol.int/eec/gallery/content/public/document/eec/conference/paper/2005/007_Zurich_Airport_emissions.pdfhttp://www.isa-software.com/Alaqsstudyhttp://www.janicke.de/data/lasport/lasport-2.0.pdfhttp://www.rivm.nl/bibliotheek/rapporten/736301008.htmlhttp://www.ipcc-nggip.iges.or.jp/public/gp/bgp/2_5_Aircraft.pdfhttp://www.ipcc-nggip.iges.or.jp/public/gp/bgp/2_5_Aircraft.pdfhttp://www.ipcc-nggip.iges.or.jp/public/gp/bgp/2_5_Aircraft.pdfhttp://www.ipcc-nggip.iges.or.jp/public/gp/bgp/2_5_Aircraft.pdfhttp://www.rivm.nl/bibliotheek/rapporten/736301008.htmlhttp://www.janicke.de/data/lasport/lasport-2.0.pdfhttp://www.isa-software.com/Alaqsstudyhttp://www.eurocontrol.int/eec/gallery/content/public/document/eec/conference/paper/2005/007_Zurich_Airport_emissions.pdfhttp://www.eurocontrol.int/eec/gallery/content/public/document/eec/conference/paper/2005/007_Zurich_Airport_emissions.pdfhttp://scholar.google.fr/scholar?q=Antoine+N.+Aircraft+Optimization+for+Minimal+Environmental+Impact&hl=fr&as_sdt=0&as_vis=1&oi=scholarthttp://scholar.google.fr/scholar?q=Antoine+N.+Aircraft+Optimization+for+Minimal+Environmental+Impact&hl=fr&as_sdt=0&as_vis=1&oi=scholarthttp://scholar.google.fr/scholar?q=Antoine+N.+Aircraft+Optimization+for+Minimal+Environmental+Impact&hl=fr&as_sdt=0&as_vis=1&oi=scholart


13/13

Wayson R, Fleming G, Lovinelli R. Methodology to estimate particulate matteremissions from certified commercial aircraft engines. J Air Waste Manag Assoc2009;59:91-100.

Yu K, Cheung Y, Cheung T, Henry R. Identifying the impact of large urban airports onlocal air quality by nonparametric regression. Atmos Environ 2004;38:45017.

Jermanto Kurniawan graduated from the Department of Civil Engineering, Faculty ofEngineering, University of Indonesia in 1997. He received a Master of Transportation atBandung Institute of Technology in 2003. Since 2008, he is a student for the DoctoralProgram at the Department of Civil Engineering, Faculty of Engineering, University ofIndonesia. Beside that he is working as a government employee in the Ministry of

Transportation Indonesia, Directorat General of Civil Aviation, Directorat of Airportssince 1998 and until now. He is working at INRETS France in the framework of theCooperation between University of Indonesia, INRETS France and the Ministry ofTransportation Indonesia since September 2009 as a researcher on environmentalimpact of aircraft noise and pollutant emissions.

Salah Khardi is a physicist and researcher, Ph.D.-HDR, in Laboratory of Transports andEnvironment The French National Institute for Transport and Safety Research(INRETS) France. His research activities focus on aircraft noise and aircraft pollutantemissions and airport environmental capacities. He is also a lecturer in differentuniversities and responsible for Ph.D. candidates.


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