Caracterización físico-química del material particulado en la comunidad foral de navarra

Resumo

The present work deals with the study of air pollution in Navarra, focusing on the characterisation of particulate matter. To achieve this goal, a sampling study was carried out during 2009 at rural (Bertiz), urban (Iturrama) and traffic (Plaza de la Cruz) stations, located in Bertiz Natural Park and Pamplona respectively. 24-h samples of PM10 and PM2.5 were collected onto quartz fibre filters every three days from January 2009 to December 2009. A total of 561 samples of PM10 and PM2.5 were collected from which about 374 were selected to be chemically analysed The first section of this thesis was focused on the development of a robust method for accurate and precise quantification by ICP-MS of Na, Mg, Al P, K, Ca, Fe, V, Ti, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Rb, Cd, Sb, Cs, Ba, La, Ce and Pb, present in MPA sampled on quartz fibre filters, in order to minimize the time of the analysis. Following, the time series of PM10, PM2.5, CO, NO, NO2, SO2 and O3 pollutants were studied at three sampling stations. This study concluded that MPA levels recorded in 2009 in Navarra were similar to those in most of the stations in northern Spain and no MPA concentration exceedances were observed, when compared to limit values established by European legislation (Directive 2008 / 50/CE). However, the average concentration of NO2 reached at Plaza de la Cruz in 2009, exceeded the annual limit set by Directive 2008/50/EC. The chemical characterization of MPA (OM + EC, mineral matter, SIC and sea spray), was consistent with the composition shown by rural, urban and traffic background stations in Spain and Europe. However, metal concentrations showed significantly lower concentrations than those recorded at other stations with similar characteristics. PMF model identified 5 principle sources for PM10 and PM2.5 in Iturrama and Plaza de la Cruz (crustal, secondary sulphate, secondary nitrate, traffic and sea-salt aerosols) and 4 sources for PM10 in Bertiz (crustal, secondary sulphate, secondary nitrate and sea-salt). These factors explained in Iturrama 96% and 98% of the total mass measured in PM10 and PM2.5 fractions respectively, 101% (PM10) and 90% (PM2.5) mass of MPA in Plaza de la Cruz and the 95% of PM10 in Bertiz. From the time series study, a classification of the main sources of MPA high level episodes in Navarra was established as follows: 1) intrusion of air masses of North African origin, 2) transport of air masses from central Europe, 3) local pollution emissions (Pamplona), 4) local pollution episodes in Bertiz, and 5) less frequent episodes of regional pollution. In the same way, the advection of air masses from the Atlantic Ocean was identified as the most frequent meteorological event (60%) in Navarra, and characterised by the presence low concentrations of particulate matter. Samples corresponding to those characteristic episodes of high contamination events in Navarra were analyzed by scanning electron microscopy (SEM-EDX). The results indicated that North African influenced samples showed typical particles of Saharan origin, such as fragments of diatoms, quartz and clay particles. In samples related to European influences many spherical carbon particles and clusters of C, Ca and Si were found, related to the use of fossil fuels, as well as soot aggregates emitted from diesel vehicles. In order to complete the chemical characterization of MPA a study concerning the characterization and source apportionment of the Polycyclic Aromatic Hydrocarbons (PAHs) in PM10 samples at Bertiz, Iturrama and Plaza de la Cruz was carried out. The limit of 1 ng m-3 of Benzo(a)pyrene set by Directive 2004/107/ was not exceeded in any of the studied areas during 2009. The principal component analysis (PCA) identified the use of fossil fuels (natural gas, Wood and coal) as the main emission source of PAHs in urban station (Iturrama) unlike, in Plaza de la Cruz and Bertiz, the emissions from diesel and gasoline vehicles were the main contribution of PAHs.