OPTOELECTRONICS AND ADVANCED MATERIALS – RAPID COMMUNICATIONS Vol. 2, No. 12, December 2008, p.

851 - 854

Method for determination of an emission factor for a

surface source
I. IONEL*, S. IONEL, F. POPESCU, G. PADURE, L. I. DUNGAN, D. BISORCAa
Politehnica University of Timisoara, Bv. M Viteazu No 1, 300223, Timisoara, Romania
a
ISPE Timisoara, Bv Gh Lazar, 18-20, Timisoara, Romania

It is known that cross roads are intensively polluting surface sources, first of all because of the high intensity of traffic, but
also due to the very slow velocities of the motor driving cycles that occur, disadvantaged also by the old status of the fleet.
As result, high momentum values of NOx and CO are recorded. The development of a modern city, the traffic refreshment
and the limitation of heavy trucks in the central area of a city that is not benefiting of good advection, but of a bad
infrastructure and ancient traffic fleet, are essential. Thus, after a long repeated series of on line measurements, the authors
are recommending a statistical approach of determination of a specific emission factor, that might be used, in same or
similar meteorological conditions and topography for limiting the traffic or characterising the by completing the emission
inventory of a city also by superficial pollutant sources.

(Received September 24, 2008; accepted November 27, 2008)

Keywords: Optoelectronic instruments, Air quality, Numerical analysis, Surface sources, Emission factor

1. Introductory explanation on the climate conditions, but also on the structure of the
fleet.
Air quality in urban areas might be determined either Literature is offering a lot of sophisticated or more
by direct, on line measurements, or by numerical simple possibilities, for calculating, with a higher or only
simulation, based on real data and meteorological & approximate accuracy, and with respect to different
topographic conditions. Another method might be the sources, from parking places, cross roads, stationary point
physical modeling, in a wind tunnel. All three possibilities sources, etc. [9], [10]. Unfortunately, the fleet composition
involve a lot of incertitude. Most appropriate and closer to and its shape are in Romania, very untypical for an
the reality are the on line measurements, which answer in European country, meaning that the structure of the fleet
real time and offer the most complex, but also the most and its technical status are not of best quality, and are far
costly, information. In Romania a new legislation, from the state of art, presently existing in the European
concerning air quality monitoring has been recently Community. Thus specific research, typical for local
developed, in accordance to the EC norms [1], [2]. conditions is to be accomplished. Appropriate
Standard measurements are based on special measuring meteorological information must be known, in order to
methods [2]. In addition new methods, such as the optical make all the necessary transformation and find possible
ones, are used [3]. For accomplishing a correct air quality explanations for a bad diffusion of the pollutants [12],
simulation, one must base on an environmental inventory [13].
of the sources, that are generally speaking, point sources, The present paper is based on long term on line
and surface (superficial) sources. For the point sources, it measuring campaigns, organised in open air in the plan
is relative easy to determine the intensity (flow, specie, city Timisoara, accomplished with standardised and non-
coordinates), as mainly they are owned by industrial or standardised apparatus, and offers a possible solution for
energy sector [5], [6] [7], [18], [19], [20]. Actually the evaluating the intensity of superficial polluting sources,
house hold sources (also stable sources), even they are of mainly the cross roads.
reduced intensity, are under control ISCIR). For
superficial sources (meaning especially cross roads), it is
difficult to establish a concrete and representative value, as 2. Experimental
it depends drastically on the traffic that is traversing
trough. Following apparatus have been used, in accordance to
Because lack of apparatus, and lack of professional the Romanian standards for air quality that are in close
care and capabilities, it is still not possible to achieve the correspondence to the EU legislation. Detailed description
continuous air quality monitoring standards, despite the is offered in [4], [10], [12], and [15].
existing legislation. Thus specific modalities for • CO HORIBA APMA-350E classic monitor working
evaluating the strength of the sources that are polluting ND in IR (called classic method in the following),
must be determined. The specificity is connected not only
852 I. Ionel, S. Ionel, F. Popescu, G. Padure, L. I. Dungan, D. Bisorca

• IR Hawk from Siemens Environmental Systems is an

NOx, 1 h
infrared DOAS instrument working as an optical 700.0
remote instrument for CO, 600.0
500.0
• NOx measuring apparatus Monitor Labs 8840 400.0
applying the principle of the chemiluminiscence, 300.0
200.0
• Monitor Labs 8850S for SO2, working in UV, 100.0
0.0
• Particle sampler LVS3 for PM10. … i… … … …
u
z ts la lo a j…
Fig. 1 gives the schematic view of the entire analysed a a a e g as
r g a
l a
cross road and indicate the grid used for the aria te r d n
i a e a B P
V t le
calculation and the position of the traffic counters. Fig. 2 i M a n
a
a a t C h i
brings one example of the on line air quality ih -P ic c
u
M L min
Day AverageMvalues 60
measurements, accomplished at Timisoara during 2002
and 2004, by the authors. Figs. 3 and 5 present particularly NOx [mg/m3N]
results, respectively, for two large cross roads of the city
of Timisoara, during the mentioned 2003 episodes. It is Fig. 2. NOx concentration, average for 1 h, and
obvious that the measured concentration values are under maximum values, by day and by night, for all monitored
close influence caused by the traffic. One remarks the Timisoara episodes.
daily peaks, and the nigh relaxation.
The maximum values are due to the traffic, and not to 10.00
Michel CO HORIBA [mg/m3N]
600

the activity of stationary sources, that are sending by 9.00

Michel CO HAWK [mg/m3N]
500
Michel Trafic
dispersion their pollutants, into the analysed cross section. 8.00

The point sources do not have regularly an interruption of

Concentration [mg/m3N]

7.00
400

Trafic Vehicles
their activity, and even if this might be the case, the 6.00

differences between the episodes are not so obvious and 5.00 300

4.00
discrepant one against the other [8], [17], [11]. Thus the 200
3.00
question proposed for analysis trough the title of the paper
2.00
finds an evident and simple answer. 1.00
100

0.00 0
17/04/03 18/04/03 18/04/03 19/04/03 19/04/03 20/04/03 20/04/03 21/04/03
12:00:00 00:00:00 12:00:00 00:00:00 12:00:00 00:00:00 12:00:00 00:00:00
Time

Fig. 3. Correlative CO mean values recorded with two

comparative measuring devices and the traffic intensity,
during a spring episode, as registered in the cross road
Michelangelo from Timisoara, in 2003.

3. Calculation methodology of the emission

factor

One determined the following values and constrains:

22,4 273,15 + t 1,013 ⋅ 105 [mg/m3N]

C =C ⋅ ⋅ ⋅
m v M pol 293,15 p
b
(1)

where:

Cm - mass concentration of the pollutant, in ppm,

Cv - volumetric concentration of the pollutant, in mg/m3N,
Mpol - molar mass of the pollutant, in kg/kmol,
22,4l - molar volume under normal conditions, in
m3/kmol,
t - temperature, °C
pb - barometric pressure, in Pa.
Thus the mean value becomes:
n
Fig. 1. Geometry and schematic of the Michel Angelo
cross road and the position of the traffic counter of the
∑ (C )
m i
[(C m ) med ]i = i =1 [mg/m3N] (2)
fleet intensity. n
 Method for determination of an emission factor for a surface source 853

where:
[(C m ) med ]i [mg /(m3N⋅m2)] (5)
n is the simultaneous registered traffic values, f sup erf =
π ⋅ rechiv
2
⋅ N cor
i - specie of the pollutant.
The equivalent dimension of the analysed cross road.

2⋅ A 4. Results and conclusions

rechiv = [m] (3)
P Figs. 4 and 6 indicate the obtained specific values for
the emission factor. It is obvious that during day and night
where: different values are specific. But also it is remarkable that
the values are quite constant and thus representative. The
A is the area, in m2, method has been repeated and attested for another 3 cross
P - perimeter, in m. roads in the meteorological and climate and topographic
One calculates specific and corrected traffic intensity conditions specific to the city of Timisoara (plain, 80 m
(number): over sea, continental climate with Mediterranean
influence, high ground water level that determines
t
N k ⎛ lk ⎞ probably temperature inversions). The curves inform about
N cor = ∑ ⋅ ⎜⎜ + t statk ⎟⎟ (4)
the evolution of the defined specific superficial emission
k =1 3600 ⎝ wk ⎠ factor, as resulted from the calculation, according to the on
line measurements. Their mean values have been recorded
where: in Table 1.
Closing concluded remarks are referring to the utility
N - the number of internal combustion engines of different and modality of evaluating air quality in a cross road, that
categories, in h-1, has been preliminary analysed. The method is very useful
3600 - transformation factor seconds/hour, as it might be used, in lack of measurements, to
k - classification index specific to the category of engine, characterise the emission capability of the analysed cross
w - mean value of the velocity for the cross road traversing road. On other side, by using that maximum admitted
of the vehicle, in m/s, value according to the legislation, in stead of the measured
t stat - stationary interval of the vehicle, in s, one, one might determine the maximum number of cars
l - length of the distances necessary for the vehicle to that might traverse the cross road, in order not to have bad
traverse the cross road, in m. air quality.
Finally, a specific superficial emission factor for the
cross road is to be calculated.

Table 1. Results for the average calculated specific emission factors, by day and by night, for different cross roads.

Cross Road Time interval fsuperf CO Horiba fsuperf CO Hawk

mg/(m3N*m2) mg/(m3N*m2)
Michelangelo Day (05 – 24) 0.00012 0.00011
Night (01 –04) 0.00050 0.00076
Marasti Day (05 – 24) 0.000072 0.000063
Night (01 –04) 0.00047 0.00043

30 6000
0.00350
Marasti CO HORIBA [mg/m3]
Michelangelo
Marasti CO HAWK [mg/m3]
0.00300 Supref CO HORIBA 25 5000
Marasti Trafic
[mg/m3N*m2]
fsuperf [mg/(m3N*m2)]

0.00250 Superf CO HAWK

Concentration [mg/m 3N]

[mg/m3N*m2] 20 4000
Trafic Vehicles

0.00200
15 3000
0.00150

0.00100 10 2000

0.00050
5 1000
0.00000
17/04/03 17/04/03 18/04/03 18/04/03 19/04/03 19/04/03 20/04/03 20/04/03 21/04/03 21/04/03
00:00:00 12:00:00 00:00:00 12:00:00 00:00:00 12:00:00 00:00:00 12:00:00 00:00:00 12:00:00 0 0
30/11/02 30/11/02 01/12/02 01/12/02 02/12/02 02/12/02 03/12/02 03/12/02
Time
0:00:00 12:00:00 0:00:00 12:00:00 0:00:00 12:00:00 0:00:00 12:00:00
Time

Fig. 5. Correlative CO mean values recorded with two

Fig. 4. Calculated superficial specific emission factor
comparative measuring devices and the traffic intensity,
for the Michelangelo cross road.
during a winter episode, as registered in the cross road
Marasti from Timisoara, in 2003.
854 I. Ionel, S. Ionel, F. Popescu, G. Padure, L. I. Dungan, D. Bisorca

0.00080 [8] I. Ionel , Impact on the air quality due to Romanian

Marasti
0.00070
Supref CO HORIBA
[mg/m3N*m2] power plants, VDI Verlag, Fortschritt Berichte, Reihe
0.00060
Superf CO HAWK
15(233), ISBN 3 18 323315 0 Düsseldorf, (2001).
fsuperf [mg/(m3N*m2)]

[mg/m3N*m2]
0.00050 [9] I. Ionel, P. Sturm, Berechnung der PKW Emissionen
0.00040 in einem Parkplatz, Conferinta aniversara 50 ani UT
0.00030 AGRA TECH 98 Cluj-Napoca, Sectiunea protectia
0.00020 mediului, II, 264 (1998).
0.00010 [10] I. Ionel, C. Ungureanu, D. Lelea, Fl. Stoian, M.
0.00000 Lörinczi, Short term average levels for the pollutants
29/11/02 30/11/02 30/11/02 01/12/02 01/12/02 02/12/02 02/12/02 03/12/02 03/12/02 04/12/02
12:00:00 0:00:00 12:00:00 0:00:00 12:00:00 0:00:00 12:00:00 0:00:00 12:00:00 0:00:00 CO, NOx, and SO2 in the city of Timisoara, Romania,
Time
Mitteilungen TU Graz, Austria, Heft 68, 299 (1996).
[11] I. Ionel, C. Ungureanu, Termoenergetica si mediul,
Fig. 6. Calculated superficial specific emission factor for Ed. Tehnică, Bucuresti, (1996).
the Marasti cross road. [12] I. Ionel et al., Monitorizarea calităţii aerului prin
gestionarea surselor de poluare (grant CNCSIS tip A),
cod CNCSIS 812, 23 (2003).
Acknowledgements [13] I. Ionel et al., Program CORINT, EU-RO,
41/04.11.2003, cu Ministerul educatiei, cercearii si
The presented tests have been achieved in the frame tineretului, „Masurarea calitatii aerului cu metode
of the ROSE (Remote Optical Sensing Evaluation) project, optice”, (2003-2004).
contract no. GR6D-CT2000-00434, funded by the EC. [14] I. Ionel, P. Sturm, D. Lelea, C. Ungureanu,
Also the scientific and financial support from CNCSIS Environmental impact of a big store market, MVM
[12] and CORINT research program [13] are to be 2000, Int. Scientific Symposium, 5-7. Oct., Print by
remarked. The financial support from the Ministry of “Zastava automobili”, Kragujevac, 17 (2000).
Education and Research is warmly thanked, for the [15] I. Ionel, P. Sturm, D. Lelea, C. Ungureanu, Fl. Stoian,
collective TOP project [1]. One addresses warm thanks Air dispersion modelling of the environmental
also to the organisers of the conference and the pollution caused by traffic, Mobility &Vehicles
anonymous referees. Mechanics, 25(2-3), 61 (1999).
[16] I. Ionel, Theoretical and experimental research
concerning air quality in the city of Timisoara, The
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07632, (1989). Corresponding author: ioana.ionel@mec.upt.ro