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