Medio Ambiente

Atmospheric Environment 44 (2010) 4879e4890

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Atmospheric Environment
journal homepage: www.elsevier.com/locate/atmosenv

Monitoring of sources and atmospheric processes controlling air quality
in an urban Mediterranean environment
Jorge Pey a, *, Andrés Alastuey a, Xavier Querol a, Sergio Rodríguez b
a

Institute of Environmental Assessmentand Water Research, CSIC, Lluis Solé i Sabarís s/n, 08028 Barcelona, Spain
Izaña Atmospheric Research Centre, AEMET Joint Research Unit to CSIC “Studies on Atmospheric Pollution”, La Marina 20, planta 6, Santa Cruz de Tenerife,
E38071 Canary Islands, Spain
b

article info

abstract

Article history:
Received 14 April 2010
Received in revised form
12 August 2010
Accepted 13 August 2010Different monitoring parameters (PM mass concentrations, numberesize distribution, black carbon,
gaseous pollutants, and chemical composition, among others) are currently used in air quality studies.
Urban aerosols are the result of several sources and atmospheric processes, which suggests that a single
monitoring technique is insufficient to quantitatively evaluate all of them.
This studyassesses the suitability of a number of monitoring techniques (PM mass concentrations,
number and size distribution of ultra-fine particles, levels of gaseous pollutants, and a complete chemical
characterization of PM10 and PM2.5) by examining the response of those techniques to the different emission
sources and/or atmospheric processes affecting an urban Mediterranean area (Barcelona, NESpain).
The results of this work reveal that the PM mass, the number concentration and the chemical
composition give different, but complementary, information. Whereas the mineral matter, a key atmospheric aerosol component across the Mediterranean, is not properly quantitatively assessed by measuring
sub-micrometric particles, the monitoring of the number concentration is indispensable to interpretthe
origin of specific aerosol episodes. Furthermore, the chemical composition yields very relevant information to deduce the causes of specific pollution episodes.
The number concentration of ultra-fine particles in urban areas is strongly dependent upon vehicle
exhaust emissions, which may cause adverse health impacts. Moreover, urban Mediterranean environments are favourable to producenucleation-mode particles (DLV

Unaccounted
Unaccounted >DLV

µg/m

3

80
60
40
20

20/12/2004

24/11/2004

09/12/2004

18/11/2004

02/11/2004

21/10/2004

05/10/2004

14/09/2004

27/09/2004

02/09/2004

02/08/2004

18/08/2004

24/07/2004

15/07/2004

22/06/2004

07/06/2004

27/05/2004

10/05/2004

28/04/2004

13/04/2004

23/03/2004

11/03/200424/02/2004

27/01/2004

12/02/2004

15/01/2004

18/12/2003

25/11/2003

04/12/2003

17/11/2003

05/11/2003

0

Fig. 6. Daily PM10 composition in Barcelona from November 2003 to December 2004. Arrows indicate those days with African dust contribution enough to provoke the exceedance
of the daily limit value of 50 mg mÀ3 of PM10. Black triangles spot those days with an unaccountedfraction sufficient to report for a PM10 exceedance of the daily value of 50 mg mÀ3.

a consequence of resuspension of urban dust and the contribution of
mineral matter from demolitioneconstruction activities, showing
a decreasing trend from 18 h local time. PM1 recorded, however,
smooth increments during traffic rush hours. Conversely, SO2
although increasing during traffic rush hours, peaksat midday. This
fact indicates that other source, in addition of road traffic, is emitting
SO2 at this urban site (probably the entrance of the marine breeze,
maximum at midday, brings the shipping emissions enriched in SO2
inside the city). O3 levels and DpNmax (diameter in which the highest
concentration of number of particles occur) show deep minima
during rush hours (O3 is consumed and...