Estimating Aircraft Emissions and their Relative Impact on overall Ambient Air Quality over D lhi Delhi Manju Mohan 1 and Jemson Rupini 2 1 Center for Atmospheric Sciences, Indian Institute of Technology-Delhi Indian Institute of Technology Delhi New Delhi, India email:[email protected]2 Chawmanu R.D Block Dhalai District, Tripura International Workshop on Regional and Intercontinental Transport of Air Pollution 13-14 October 2008; Hoa Binh Hotel Hanoi; Vietnam Pollution, 13-14 October, 2008; Hoa Binh Hotel, Hanoi; Vietnam
Transcript
Estimating Aircraft Emissions and their Relative Impact on overall Ambient Air Quality over
D lhiDelhi
Manju Mohan1 and Jemson Rupini2
1Center for Atmospheric Sciences,Indian Institute of Technology-DelhiIndian Institute of Technology Delhi
International Workshop on Regional and Intercontinental Transport of AirPollution 13-14 October 2008; Hoa Binh Hotel Hanoi; VietnamPollution, 13-14 October, 2008; Hoa Binh Hotel, Hanoi; Vietnam
Background
Air Travel is undertaken merely by 5 percent of theld’ l iworld’s population
A person flying a distance of 10,000 km (two ways) ends upp y g , ( y ) padding more than a tonne of CO2 (Air France/KLMreport)
Contribution of the civil aviation sector-passenger andfreight to Climate Change is 4-9 %. However, the totalclimate impact of NOx emission is 2-5 times greater thanCO l NO i th t j ll t t fCO2 alone. NO2 is the amongst major pollutant fromaircrafts
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Operation of Aircrafts
The Landing and Take-off (LTO) cycle: It includes all theg ( ) yactivities near the airport below the altitude of 3000 ft
Cruise :All the activities at altitude above 3000 ft
Ai t ffi t di i th t f t h h dAir traffic studies in the upper part of troposphere showedthat about 60% of aircraft NOx was generated between 10-12 km of which 93% is in Northern Hemisphere that mayincrease few percent of global ozone concentrations in thisatmospheric layer
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Present work deals only with the LTO cycle emissions; thisis less studied as per literature and focus of the present
Background
Air traffic in India has substantially high growth rate.
R l d l t i t i li h b t 85% f thRegular and low cost private airlines shares about 85% of thepassenger air traffic.
IGI airport at Delhi is the second busiest airport in India and aboutIGI airport at Delhi is the second busiest airport in India and about23% air traffic in the country is shared by this airport.
There is a continuous increase in NO2 concentrations in Delhi thoughth h b l ti i t i i lit f th ll t tthere has been relative improvement in air quality of other pollutantssuch as CO due to introduction of CNG and improved emissionstandards.
Could air traffic be responsible for this which is not accounted for inthe regular city emissions?
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Annual Trends of NO2 in Delhi2
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Annual distribution of aircraft movements at IGI airport
S AAI d D lhi I i l Ai (P) L d (DIAL)S AAI d D lhi I i l Ai (P) L d (DIAL)
Years
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Sources: AAI and Delhi International Airport (P) Ltd (DIAL)Sources: AAI and Delhi International Airport (P) Ltd (DIAL)
i i i i iThere is 2.4 times increase in Aircraft movements from 2000 to 2007 (i.e., from 95,720 in 2000 to 2,26,300 in 2007)
Average Landing and Take off (LTO) cycle in 2005 was 520 perAverage Landing and Take-off (LTO) cycle in 2005 was 520 perday which rose to 675 per day in 2008
The exhaust emission from aircraft are CO2, water vapour,The exhaust emission from aircraft are CO2, water vapour,NOx, SOx, CO, non methane hydrocarbon, other gases andparticles.
It is expected that these emissions may add to the air pollutionproblems of megacities.
It i th f t tif i i f i ftIt is therefore necessary to quantify emissions from aircraftmovements and assess the magnitude of impact on ambient airquality.
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Objectivesj
Assessment of aircraft emissions of key airypollutants at IGI Airport in Delhi
Impact of aircraft emissions on urban air quality
T th t ib ti f i ft i i tTo assess the contributions of aircraft emissions tothe total city emissions and ambient airconcentrations of an urban airshed.
Compare the estimates with other studiesd t d l h i th ld
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conducted elsewhere in the world
Operation of Aircrafts
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Time and Thrust Setting in Operation Phase
Operating phase Time-in-mode (minutes)
Thrust setting(percentage of rated thrust)
Approach 4.0 30
Taxi and ground idle (in)
7.0 7
Taxi and ground idle (out)
19.0 7
Take-off 0.7 100
Climb 4.2 85
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Aerial view of IGI AirportAerial view of IGI Airport
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P ki b t IGI i tMohan and Rupini
HTAP Hanoi Workshop, 13-14 Oct., 2008
Parking bay at IGI airport
Operation of Aircrafts Contd.
In this study, the times for approach, taxi, take-off andy, pp , ,climb are taken from a standard LTO cycle; i.e. 4 min forapproach, 26 min for taxi, 0.7 min for take-off and 4.2minute for climbminute for climb .
Fuel consumption and emission indexes of an aircraft forue co su pt o a d e ss o de es o a a c a t oeach operation mode are taken from the ICAO-Engineemissions data bank.
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Aircraft Emission Calculations
Ei,m=∑∑na la.e Fa,e,m Ee,m,i tm,a
Ei,m annual emission of pollutant i for mode m, (kg/yr)
na number of engines of aircraft type a, (-)na number of engines of aircraft type a, ( )la.e number of annual LTO cycles for aircraft type a with engine
type e, (-)Fa,e,m fuel consumption for aircraft type a with engine type e in mode m,(kg/s)a,e,m p yp g yp ( g )
Ee,m,i emission factor for engine type e and mode m and pollutant i, (g/kg)
tm,a time in mode m for aircraft type a, (s).
(Developed by Woodmansey & Petterson)
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Emissions Calculations
Emission of Species X = Σ ([Number of LTO cycles) x (Emissions Factor)(i k ) All Ai f f Ai f Y f S i X(in kg) All Aircraft of Aircraft Y for Species X
Fuel consumption = Σ [Number of LTO cycles] x [Fuel Consumption]Fuel consumption = Σ [Number of LTO cycles] x [Fuel Consumption](in kg) All Aircraft of Aircraft Y
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Aircraft LTO emissions at IGI airport for 20052005
Estimated amount Estimated amount Estimated total of LTO emissions from International flights
Comparision of aircraft LTO emission at IGI airport for 2005 (estimated based onComparision of aircraft LTO emission at IGI airport for 2005 (estimated based on assumes aircrafts distribution at Ataturk Turkish airport and actual distribution of
aircrafts types at IGI airport)
5898.686000
7000
r
4057.65
3169.4044000
5000
6000
sion
s in
t/yr
2252.52
1313.2362180.053
1000
2000
3000
LTO
em
iss
424.1 67.8328.0 221.230
HC CO NOX SOX Total
Aircrafts emissions
LTO emission at IGI airport calculated with reference to aircrafts distribution at Ataturk Turkish airport
LTO emission calculated with actual distribution of aircrafts types in IGI ariport
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Aircraft LTO Emissions at IGI Airport for 2007
Estimated amount of LTO emissions fromInternational flights
Emissions are continuous (aircraft movement is continuous andequispaced) throughout the day that leads to
Steady state emissions
Ground level area source ( wake vortices have a downward thrust andcontributes more to glc and extremely high emission temperatures andrunway movement help in rapid mixing to create a single box likesituation and maximum emissions during ground idle or taxi (in out)situation and maximum emissions during ground idle or taxi (in-out)phase
Thus a Gaussian ground level area source model is applied
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Thus a Gaussian ground level area source model is applied.
Air Quality ModellingQ y g
ISCST-3 model also recommended by MoEF, GoI isl dselected
ISCST-3 model was applied to predict 24 hourly averagepp p y gand annually averaged concentrations of NO2 and SO2, byusing the meteorological data and emission inventory ofDelhi
The ambient concentration of NO2 and SO2, from theaircraft at IGI airport was also estimated by using ISCST-3 d l3 model
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STUDY AREAS U
IGI Airport
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Decade-wise Trend of Distribution of Various Sources
Annual Trends of Emissions of Various Pollutants in Delhi
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G id l ifi ti f D lhi h i th l ti f it i t ti d IGI i t
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Grid classification of Delhi showing the locations of monitoring stations and IGI airport
Methodology contd.
Comparisons of Model Results with CPCB Observedvalues.
M d l ti t f id d th i tModel estimates for grids around the airport
Contour representation of highest 24 hours averageContour representation of highest 24 hours averageconcentrations and annual average concentrations for allthe grid
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Annual NOX Concentrations from Aircraft Emissions
Annual Average Concentration of NOX (all site)for 2004 at Delhi City (µg/m3)
Emission Emission Percentage concentration
with IGI airportconcentration without IGI
i
gincrease due to contribution of
i(µg/m3)
airport(µg/m3)
IGI airport emission
53.3 52.0 2.3 %
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Annual Average Concentration of NOX at Delhi City (µg/m3)
G id 106 62 4172 52 0663 19 8802 %Grid 106 62.4172 52.0663 19.8802 %
Grid 114 42.3792 39.0494 8.52715 %
Grid 117 63.7693 49.7133 28.2749 %
Grid 125 43.2531 39.5714 9.3051 %
Grid 128 50.3442 44.4471 13.2679 %
Grid 137 33.4563 31.1011 7.57272 %
Grid 138 42.1054 39.5827 6.3732 %
Grid 139 46.2599 44.0254 5.0755 %
Grid 140 45 7 44 1 3 5 %
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Grid 140 45.7 44.1 3.5 %
Contour Representation
Concentrations contour for NOX without IGI airport (Highest 24 hours average concentrations)
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(Highest 24 hours average concentrations)
Concentration contour for NOX with IGI airport (Highest 24 hours average concentrations)
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g g
Concentration contour for NOX without IGI airport for 2004(Annual average concentrations)
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(Annual average concentrations)
Concentration contour for NOX with IGI airport for 2004(Annual average concentrations)
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(Annual average concentrations)
Another Case Study
By Pison and Menut, 2004:
Study Area: Parisone national airport (Le Bourget)two international airports (Roissy-Charles-de-Gaulleand Orly)located less than 30 km away from the city centerlocated less than 30 km away from the city centerEstimation of Aircraft Emissions
Mesoscale version of the CHIMERE model was usedMesoscale version of the CHIMERE model was used
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The air traffic inventory used forthis work was developed for totalpmasses of VOCs, CO, NOx; CO2 andSO2 distributed among the four LTOphasesphases.
Total annual emitted massesTotal annual emitted masses(tonnes/year) were compared toknown emitted masses for North-American airports of various sizes(assuming similar fleets) foradjustment of uncertainties injemission data. (Figure 1 )
Figure 1: NOx and VOC emissions as functions of the number of LTOs. Circle, square
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and diamond: 1998 data for the three airports of the Paris area.
Contribution of Aircraft Emissions: Delhi
Comaparison of Aircraft Emission with Anthropogenic Emission
2.50%
3.00%
ssio
n
1.50%
2.00%
tion
of e
mis
m a
ircr
aft
0.00%
0.50%
1.00%
Con
tribu
tfro
m
CO2 NOX CO SO21
Aircraft emissions
HCNO2CO
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Results: Paris StudyAi f E i i i P i f NO b 6000Aircrafts Emissions in Paris for NO2 are about 6000tons/year (Figure i) for year 1998 while for the present studyaircraft emissions contribute about 3803 tons/year for NO2 iny 22007.
Contribution of Aircraft NOx emissions towards total NOxemissions ~ 13.25 % for Paris [Table 1](against 2.4 % forpresent study in tonnes/year)p y y )
Table 1: Emitted masses during a weekday (24 h) in the whole area (tons)
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Results: Paris StudyCHEMERE model results for Paris study shows that the maximumnegative impact of air traffic emissions on Ozone concentrations happenat night and consists in a decrease of already low Ozone concentrationd t f t O tit ti b NOdue to fast Ozone titration by NO
The maximum positive impact happens at daytime in remote areas andat altitude where the chemical system is not saturated with NO
In areas where chemical system is saturated with NO, the increase ofy ,NOx accentuates the Ozone concentration and vice-versa. The evolutionis opposite in non saturated areas
As per this study, net impact is negative showing that airports induceenhanced titration of Ozone by NO
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Conclusions
Aircraft emissions has less significant impact on total cityemissions in Delhi
However, aircraft emissions have significant localised effecton the Ambient Air Quality. An increased concentrationsQ yupto 28% (approx. 14 µgm-3) in the present case is estimated
Air traffic is expected to increase worldwide at the 5%Air traffic is expected to increase worldwide at the 5%annual growth rate. The expected increase is far greater forAsia-Pacific region which is about 50% of worldwide traffic.In this context, the aircraft emissions are potential sourcesthat may lead to deterioration of the local air quality
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Conclusions contd.Air traffic emissions significantly impact the Ozone chemistrydepending upon the presence of NOx in the emitting atmosphere
Aircraft emissions also have great potential to significantly impact theaerosol chemistry
Air traffic emissions increases both greenhouse gas emissions and otherair pollutants; all these emissions together could subsequently lead toclimate changeclimate change
Future studies needed to quantify these impacts on atmosphericchemistry vis à vis emissions for varying size of air trafficchemistry vis-à-vis emissions for varying size of air traffic
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AcknowledgementsAcknowledgements
Delhi International Airport (P) Limited (DIAL)India Meteorological DepartmentC l P ll i C l B d D lhiCentral Pollution Control Board, DelhiCAS and CE Dept., IIT Delhi USEPA and EUUSEPA and EU
