| The general search objectives in this thesis are: (a) to interpret the variability of PM10 and PM2.5 levels in the environment and that of their majority, minority and trace components. (b) to identify and to quantify the contributions of the air masses with African origin to PM10 and PM2.5, as well as those whose origin is in other anthropogenic or natural sources of emission.Samples from both fractions PM10 and PM2.5 have been taken in three different locations of the city of Cartagena: Bastarreche, Santa Ana and Mompean. The gravimetric determinations of levels of PM10 and PM2.5 in ambient air have been made, as well as those of the chemical speciation of the samples (ICP-MS, ICP-AES, ionic chromatography, and C, OC and EC elemental analysis). The results from the Network for Air Quality Monitoring in the Region of Murcia have been processed by elaborating the appropriate databases. In order to define the origins of the air masses, there has been a use of geographic information tools together with satellite images and results of atmospheric models. There has been a use of the appropriate methodology for studying the intrusion of air masses originating in the African deserts of Sahara-Sahel.There has been an identification of a time and spatial variability for those species under study. The biggest values for the crustal species in PM 10 have been registered in Santa Ana. In the case of those species indicating industrial activities, their levels in PM10 have been higher in Bastarreche. Concerning PM2.5, there are no data in the case of Bastarreche and the highest levels of the species studied, except for those related to the total mass, have appeared in Mompean.The events which are linked to a lower load of PM10 in the Region of Murcia correspond to those called Northern Atlantic, Northwestern Atlantic and Western Atlantic, and in these situations the increase in the levels of atmospheric pollutants is due to the activies which are characteristic in that area. Southwestern Atlantic is a common origin of dust outbreaks. The contribution which has a natural origin and a local character also appears within the Regional events, in which the anthropogenic contribution can also be noticed.The typical weak Mediterranean gradient of pressure, for which there is an African advection reaching the Region of Murcia, allows for the definition of a fifth (new) scenario, which means up to 21% of the days with dust outbreak which have been studied in this memory, and consequently, they have to be considered in order to assess the air quality in the area. It has been revealed the amount of crustal species from exogenous sources and the importance of indigenous sources, such as wheeled traffic, for the carbonaceous fraction.The African dust contribution to the PM10 annual mean is considered between 4 and 6mug/m3. In the period between January 1, 2004 and May 31, 2005, there have been 562 days with dust outbreak. It is mentioned the possibility of using as a regional background sampling station for the Region of Murcia, the one located in Caravaca de la Cruz.A decrease in PM10 levels can be observed as a consequence of changing the sampling station from Bastarreche to Mompean. The latter is a sampling station without breach of the limits, neither in the cases of PM10 and PM2.5 nor in those ones of metals subject to regulation. The differences found in PM10, between the real-time measurements of the Network for Air Quality Monitoring in the Region of Murcia and the gravimetric data, have made it necessary a detailed study of the causes which have provoked this incidence. (Abstract shortened by UMI.)... |
