THE ATMOSPHERIC POLLUTION IN URBAN ITALIAN CITIES

The seventh International Conference on Urban Climate,
29 June - 3 July 2009, Yokohama, Japan
THE ATMOSPHERIC POLLUTION IN URBAN ITALIAN CITIES
P. Avino*1
*ISPESL, Rome, Italy.
Abstract
This contribution regards three fundamental aspects of the urban pollution, sources, diffusion and chemical
composition with relative speciation, pointing out the anthropogenic activities and their relationship with the
environmental sustainability.
The chemical parameters ruled by laws (conventional pollutants) are evidenced together with other species not
ruled (no conventional pollutants) but important: scientific researches are addressed to investigate secondary
pollutants and micro-inorganic contaminants in atmosphere. Further, a task is devoted to the evaluation and
characterization of the carbonaceous component (elemental and organic carbon, EC and OC): in fact, EC can be
used as tracer for a speed evaluation of pollution state of an urban environment.
Key words: Primary pollutants; Anthropogenic sources; Urban atmosphere.
1. INTRODUCTION
The study of atmospheric pollution is one of the more interesting field for the different implications: in fact, the
knowledge of the chemical-physical reactions occurring in atmosphere and the relative effects of pollutants on the
human health are still objects of deep studies.
This contribution would like to show what the main contaminations are in urban air of Rome (Itsaly) and what
contributions are due to anthropogenic activities.
Primary pollutants are defined directly emitted from emission sources both in gaseous and particle phase
whereas secondary pollutants derive from chemical and/or photochemical reactions of primary pollutants among
them and/or other atmospheric species (Table 1) (Lepore et al., 2001).
Primary Pollutant
CO
NOx (95% NO, 5% NO2)
SO2
VOC (benzene, etc.)
PAHs
Secondary Pollutant
Ozone
NO2, HNO3, HNO2
Peroxyacetylnitrate
HCHO
Nanoparticles
PM10
Organic nitroderivates
Nitrates
Sulfates
Table 1. Main primary and secondary pollutants present in the urban air of Rome
The primary and secondary pollutants for which the Italian legislation defines acceptable maximum levels, are
known as conventional pollutants whereas for the non conventional species (e.g., HCHO) no limits are fixed.
Finally, photochemical pollution is related to the presence in atmosphere of secondary pollutants (O3, HNO2,
peroxyacetylnitrate, etc.) generated by radical reactions of nitrogen oxides and hydrocarbons and occurring in
presence of strong UV radiation (Lepore et al., 2001).
2. EXPERIMENTAL PART
From an analytical and methodological point of view, the air quality evaluation is performed by means of
dedicated equipments to determine gaseous (i.d., SO2, NOx, O3, CO, benzene, toluene and xylene, BTX) and
particulate matter (PM10) concentration levels. Further, techniques of remote-sensing can be used (e.g.,
Differential Optical Absorption Spectrometry, DOAS; Fourier Transformed Infrared spectroscopy, FT-IR) for
measuring some pollutants not subjected to high spatial-temporal difference and for evaluating species such as
nitrous acid and HCHO.
3. RESULTS AND DISCUSSION
1
Corresponding author: DIPIA-ISPESL, via Urbana 167, 00184 Rome (Italy). E-mail: [email protected]
The seventh International Conference on Urban Climate,
29 June - 3 July 2009, Yokohama, Japan
3.1. Boundary layer evolution
The interpretation of atmospheric pollution phenomena is complex for the contemporary presence of both
emission and chemical-physical processes and diffusion and transport phenomena. The meteorological
measurements give information not too much sufficient for describing the evolution of the boundary layer. A
parameter of easy interpretation and able to describe the behavior of pollutants and boundary layer t the same
time, is developed: the natural radioactivity (Avino et al., 2003). This measures allow to identify the variations of
atmospheric pollutant concentrations, expecially primary pollutants because they depends strictly on the emission
fluxes (autovehicular traffic).
3.2. Trends of primary pollutants in Rome
In Rome, during ’90-years the pollution scenarios are well-studied and interpreted: the different structural
operations and the introductions of catalytic pots and the limitations in the benzene and sulfur content in fuels
have caused a sharp reduction in benzene (Figura 1) and SO2 (Figura 2) levels since 1994.
Figura 1. Monthly (bar) and annual (lines) average levels of benzene measured in downtown Rome.
Figura 2. Monthly (bar) and annual (lines) average levels of SO2 measured in downtown Rome.
For primary pollutants a clear decreasing trend is observed whereas it results more attenuated for secondary
pollutants. These last species show fluctuations in a range compatible with the atmospheric reactivity conditions
in relationship with the atmospheric stability conditions during the complex phenomena of HC-NOx-UV reactions
not directly correlated with the emission sources (Monod et al., 2001).
A particolar look should be dedicated to pariculate matter pollutant: this is a very difficult pollutant for both its
physical properties (granulometric size) (Avino and Brocco, 2005) and natural and/or anthropogenic sources
(Avino et al., 2006). The main natural sources are vulcan eruption, rock erosion, marine aerosol, biogenic
emission, etc., whereas the main anthropogenic are specific industrial activities and combustion processes.
From a chemical point of view, Table 3 shows the elemental composition of PM10 in downtown Rome.
In urban area, expecially a megacity such as Rome can be compared, the major contribution to PM10 level is due
to anthropogenic sources like domestic heating and autovehicular traffic. In fact, to these last sources the
elemental carbon (EC) fraction is related: EC can be used as a new tool for evaluating the contamination of an
environment (Avino et al., 2003).
The seventh International Conference on Urban Climate,
29 June - 3 July 2009, Yokohama, Japan
Ag
0.176
Eu*
12.3
Ni
4.54
Zn
80.0
As
1.35
Fe**
0.566
Pb
92
Au
0.008
Hf
0.020
Rb
2.19
Ba
12.8
Hg
1.07
Sb
9.22
OC
30%
Br
22.2
K
1100
Sc*
46.1
EC
70%
Ca
1500
La*
188
Se
0.687
PAHs
2%
Cd
0.526
Mg
240
Sm*
53.4
Sulfate
40%
Ce
0.843
Mn
40.0
Th
0.204
Nitrate
25%
Co
0.379
Mo
2.10
V
4.02
Ammon
20%
Cr
7.28
Na
420
W
1.25
Cs
0.151
Nd
0.245
Yb
0.015
Table 2. Average levels (ng/m3) of elements determined in PM10 fraction in downtown Rome (*: expressed as
3
3
pg/m ; **: expressed as µg/m ).
5. ACKNOWLEDGEMENTS
This work was supported under the grant ISPESL/DIPIA/P06 “Identificazione, analisi e valutazione delle
conseguenze delle attività antropiche (Identification, analysis and evaluation of consequences of anthropogenic
activities)” L06, 2008-2010.
References
Avino, P., Brocco, D., Lepore, L., Pareti, S., 2003. Interpretation of atmospheric pollution phenomena in
relationship with the vertical atmospheric remixing by means of natural radioactivity measurements (Radon) of
particulate matter. Annali di Chimica, 93, 589-594.
Avino, P., Brocco, D., 2005. Studio delle particelle carboniose in atmosfera in relazione alle varie frazioni
granulometriche ed al contenuto di carbonio organico. Fogli d’Informazione, 3, 107-113.
Avino, P., Capannesi, G., Rosada, A., 2006. Characterization and distribution of mineral content in fine and
coarse airborne particle fractions by Neutron Activation Analysis. Toxicological and Environmental Chemistry, 88,
633-647.
Lepore, L. , Ventrone, I., Brocco, D., Avino, P., Sallusti, F., 2001. Studio dell’inquinamento atmosferico nell’area
urbana di Roma: Risultati di dieci anni di attività svolta presso la “Stazione Pilota” dell’ISPESL. Fogli di
Informazione ISPESL, 1, 62-103.
Monod, A., Sive, B.C., Avino, P., Chen, T., Blake, D.R., Rowland, F.S., 2001. Monoaromatic compounds in
ambient air of various cities: a focus on correlations between the xylenes and ethylbenzene. Atmospheric
Environment, 35, 135-149.

Download Report