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Applicability of a General Finite Line Source model for vehicular pollution prediction in Ireland.
Rajiv Ganguly
Brian M. Broderick
Roland O’ Donoghue
Department of Civil Engineering
University of Dublin, Trinity College
Overview
v Objectives
v General Finite Line Source Model (GFLSM)
v Comparison of Monitored and GFLSM data (M50)
v Comparison of GFLSM with CALINE4 (M50) v Comparison of Monitored and GFLSM (Monasterevin)
v Conclusions
Overall Research Objectives
Ø To predict vehicular pollution by using a variety of atmospheric dispersion models.
Ø To perform studies by applying a variety of dispersion models to different road configurations to ascertain the applicability of each model.
Overall Research Objectives
Ø To carry out inter-comparison of modelled data obtained by using a variety of dispersion models by performing statistical and graphical analysis.
Ø To recommend suitable atmospheric dispersion models for vehicular pollution prediction in Ireland.
Ø To compare the monitored and predicted data sets obtained by using a variety of dispersion models by performing statistical and graphical analysis.
Expression for GFLSM
( )( ) ( )
( ) ( )⎥⎥⎦
⎤
⎢⎢⎣
⎡
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛ +++⎟⎟
⎠
⎞
⎜⎜
⎝
⎛ −−
⎥⎥⎦
⎤
⎢⎢⎣
⎡⎟⎟⎠
⎞⎜⎜⎝
⎛ +−+⎟
⎟⎠
⎞⎜⎜⎝
⎛ −−
+=
yy
zzz
xyperfxyperfx
HzHzuu
QC
σ
θθ
σ
θθ
σσθσπ
2cossin
2cossin
,2
exp2
expsin22 2
2
2
2
0
1
Schematic representation of GFLSM
L
x
y R
θ
Study on M50 motorway.
Schematic Diagram of Sampling Location.
Receptors
Receptors
Secondary road
-240m -120m
-25m
25m 120m
240m
N M50 Motorway Inner suburbs and city centre
Results on M50 Motorway for Acetylene.
Spatial distribution of monitored and predicted mean concentrations .
0
0.1
0.2
0.3
0.4
0.5
0 60 120 180 240
distance from road (mt)
conc
entr
atio
n (p
pb)
monitored
CALINE4
GFLSM
Results on M50 motorway for Acetylene.
scatter plot for acetylene at 25 mt
00.10.20.30.40.50.60.70.8
0 0.2 0.4 0.6 0.8
measured
pred
icte
d
CALINE 4
GFLSM
Series3
Series4
Series5
Results on M50 motorway for Acetylene.
scatter plot for acetylene at 120 mt
00.020.040.060.080.10.120.14
0 0.05 0.1 0.15
measured
pred
icte
d
CALINE4
GFLSM
Series3
Series4
Series5
Results on M50 motorway for Acetylene.
scatter plots for predicted data at 25 mty = 0.9579x + 0.0099
R2 = 0.595
00.10.20.30.40.50.60.70.8
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
CALINE4
GFL
SM
2+900
Results on M50 motorway for Acetylene.
scatter plots for predicted data at 120 mty = 0.7491x - 0.0007
R2 = 0.6802
00.020.040.060.08
0.10.120.14
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14
CALINE4
GFL
SM
Results on M50 motorway for Acetylene.
Statistical Analysis of Monitored and Predicted data
(a) At 25 meters.
monitor CALINE GFLSM Mean .45 .36 .36 IA 1.00 .44 .55 FB 0.00 -0.22 -0.23 R 1.00 .29 .45 NMSE 0.00 .6 .6 F2 100% 55% 65%
Results on M50 motorway for Acetylene.
n Statistical Analysis of Monitored and Predicted data
(b) At 120 meters
Monitor CALINE GFLSM Mean .14 .11 .08 IA 1.00 .23 .26 FB 0.00 -.25 -.54 R 1.00 .26 .35 NMSE 0.00 3.7 5.1 F2 100% 20% 20%
Monasterevin.
Ø New M7 bypass opened in November 2004. Ø Air Quality monitored before and after opening. Ø Improvement of air quality observed.
Ø Ability of GFLSM to predict this change assessed.
Results on Monasterevin for CO.
variation of reduction of CO concentration actually observed and predicted concentration
00.050.1
0.150.2
0.250.3
0 6 12 18 24
hours of the day
conc
entra
tion
observed reduction inCO concentrationaverage modelled COconcentration
Results on Monasterevin for NOx.
variation of reduction of NOx concentration actually observed and predicted concentration.
020406080
100
0 6 12 18 24
hours of the day
conc
entra
tion
observed reduction inNOx concentrationaverage modelledNOx concentration
Results on Monasterevin for CO.
(a) Statistical analysis of monitored and predicted data.
Reduction GFLSM
Mean 0.1 0.12
IA 1.00 0.11
FB 0.00 -0.17
R 1.00 -0.54
NMSE 0.00 0.83
Results on Monasterevin for NOx.
(b) Statistical analysis of modelled and predicted data.
Reduction GFLSM
Mean 20.5 33.4
IA 1.00 0.17
FB 0.00 -0.48
R 1.00 -0.33
NMSE 0.00 1.28
Ø For the M50 motorway site the performance of GFLSM has been found to be quite satisfactory when compared with CALINE4, an USEPA reference model Ø For the Monasterevin site the GFLSM model overpredicts heavily when compared with the reduction of CO and NOx concentrations.
Conclusions
Ø Further studies are in progress to determine the applicability of GFLSM model.
Ø An analytical model, GFLSM has been discussed and has been applied at two different road configurations..
Acknowledgement.
n This work is a part of the Environment Transport Interface (ETI) project funded by the ERTDI Research Programme.
Thank You