Development of analytical techniques for the characterization of natural and anthropogenic compounds in fine particulate matter

Aerosol is of central importance for atmospheric chemistry and physics, for the biosphere, the climate and public health. The primary parameters that determine the environmental and health effects of aerosol particles are their concentration and chemical composition. In this work we have developed the analytical techniques to study particulate matter composition. The knowledge of PM composition can be useful to identify the main PM sources, the health risk and the formation or deposition/removal processes. These analytical techniques have been applied in some field campaign: we have studied the urban particulate matter, the main transport processes sampling in remote sites, the PM concentration and composition in the rural site to estimate the background levels. At the moment EU limits concern only PM10 fraction, but the interest for sub-micron sized particles (PM1) is increasing for their effects on human health and on the environment. We have carried out the first national campaign to study this fraction in three urban sites in Italy. Morevor, for a good comprehension of the complex atmospheric phenomena we have sampled at high resolution time. In the chapter 2 we reported the extraction procedure for ion quantification, to obtaine the good recovery of all ions, the lowest detection limits and to use less portion of sample as possible, to have the possibility to make a large number of analyses on the same sample. The carbonaceous fraction analysis is still object of the discussion in the scientific community, indeed there is not a reference method for this analysis. The key point of this analysis is to separate the main components of carbonaceous particles: organic carbon (OC) and elemental carbon (EC). In the chapter 3 we proposed a new analytical method based on the couple between Thermo Gravimetric Analysis (TGA) with Spectrophotometer Infrared (FT-IR) and in chapter 4 we have reported the intercomparison between this techniques an other analytical method, TOT method by Sunset Instrument. A good comparability is achieved for TC and OC while the agreement is poorer for EC, in accordance with what previously observed by other authors. In the recent years the studies involving the Water Soluble Organic Compounds (WSOC) are increasing because they represent an important portion of OC and can be an important marker of the origin of organic compounds (i.e. biomass burning, ageing). In the chapter 5 the new analytical technique for WSOC quantification using TOT method is reported; the validation of this analytical procedure with a most diffused technique (TOC analyses) is still in progress. In the same chapter we discuss around an hypothetical error in the OC and EC quantification using TOT method: indeed removing the soluble compounds from the sample the contribution of pyrolitic carbon (PyC) decreases and this allows a good determination of the elemental fraction. Nowadays, very few data on the possible contribution of particles emitted by residential wood combustion in Italy are available. In the chapter 7 we proposed a new analytical technique for levogluvoclucosan quantification. Levoglucosan is an anydrosugar specific marker for this source. Usually the anydrosugar in atmospheric aerosol samples is performed by gas chromatography - mass spectrometry (GC-MS), while we have used High Performance Anion Exchange Cromatography coupled with amperometric detection (HPAEC-PAD). This technique was shown to be a high sensitive, relatively simple analytical technique for separation and quantification of anydrosugars in aqueous extract of aerosol particle from biomass combustion. The intercomparison with GC-MS has shown a good comparability for the two techniques. Unlike traditional methods, there is not need for prior chemical derivatization or other complex sample preparation, the extraction procedure for ions quantification is suitable also for this method. The field campaigns were performed thanks to the collaboration between different partners, the Physics Department (University of Genoa), the General Applied Physics Institute (University of Milan), the Physics Department (University of Florence), the National Institute of Nuclear Physics (Florence) and the ARPA Lomabardia are the most important. In Lombardy region atmospheric pollution due to airborne fine particles is an environmental issue of great concern: air quality standards for PM10 are frequently exceeded, especially in Milan. In the ParFiL project by Regione Lombardia we have determined the carbonaceous fraction in about 1000 samples coming from ten different sites (chapter 8) in the Lombardy Region. The carbonaceous compounds are the main constituent of the particulate matter. During the summer the concentrations is quite similar in all urban sites, the average of the concentrations are for the OC 7.4µg/m³ and for EC 1.9µg/m³. During the winter the concentrations are doubled: OC is 15.3µg/m³ and EC is 4.2µg/m³. Milano and Mantova concentration result more correlated in both seasons and the background concentrations measured at Mantova BF resulted strong correlated with the urban concentrations. Using the EC tracer method and the EC concentration in Como (the traffic site) we have estimated that, in the urban site, about the 50% of OC is due to secondary formation; only Milano and Como show a percentage of primary OC higher than the secondary OC. An exhaustive discussion of this method for secondary OC estimation and its comparison with another method (PMF model) is reported in chapter 13). Using levoglucosan as a marker for wood combustion we have estimated the percentage of OC due to this source. In four urban sites, taken as example (Milano, Cantù, Mantova and Sondrio), during the winter time Milan show the lowest value of the OC due to wood combustion (25%), while Sondrio show the highest value (50%) (section 8.3). This preliminary study points out that the magnitude of this source is strong. The transport phenomena have been studied sampling in two remote sites: Monte Cimone, located in the Apennines (2165m asl) (chapter 10) and Bormio S.C. located in the Alps (2200m asl) (chapter 9). With the APCA model we have estimated that the main percentage (60%) of particle on the Monte Cimone site is due to anthropogenic sources. The physical-chemical characterization of PM10 with high temporal resolution campaign (chapter 12) allowed the individuation of the variation of the composition of the PM in the different hours of the day, and also the different magnitude of the sources during the day. The high time resolution sampling allows the study of the atmospheric phenomena (i.e. secondary formation, transport) otherwise hardly appreciable. Sub-micron sized particles (PM1) are of increasing concern owing to their effects on human health and on the environment. To perform the first large scale assessment of sub-micron sized aerosol concentrations, composition and sources, two monitoring campaigns (summer and winter) at three urban sites in Italy (Milan, Florence and Genoa) with different characteristics were performed (chapter 11). The major contributions are due to organic matter (about 30% in summer and 50 % in winter) and ammonium sulphate (about 10 % in winter and 40 % in summer). During the cold season nitrates also contribute up to 30 % in Milan (lower contributions were registered at the other two urban sites). The interest for the effects of air pollution on indoor cultural heritage is increasing. We have studied two different sites: the Ca’ Granda Historical Archive (chapter 14) and the Pietà Rondanini (by Michelangelo) storage room. In one of the two room monitoring in the Ca’ Granda resulted that the air quality is fairly good and it is not so influenced by the outdoor pollution. On the contrary the ambient conditions, in the second one, are quite worrying because of high relative humidity and PM concentration. The Pietà Rondanini storage room is strongly influenced from outdoor ambient. The presence of the visitors favours the growth of pollutants concentrations, the indoor particulate matter composition is similar to outdoor composition. The particulate matter acidity represents a potential risk for the statue.