Monitoring of atmospheric particulate matter around sources of secondary inorganic aerosol: Fid-Bau Portal

Monitoring of atmospheric particulate matter around sources of secondary inorganic aerosol

Alastuey, A. / Querol, X. / Rodríguez, S. / Plana, F. / Lopez-Soler, A. / Ruiz, C. / Mantilla, E.

AbstractA physicochemical characterisation of airborne particulate matter (PM) was performed in a region affected by the emissions from a source of precursors of secondary inorganic aerosols (SIA, 1050MW power plant). This characterisation sought to study the interferences of other possible natural and anthropogenic sources when monitoring PM10, PM2.5 and PM1 around this emission source. The study was performed in the semi-arid Ebro basin and Catalan and Iberian ranges (Eastern Spain) and consisted in (1) monitoring the transport and impacts on the ground of the ${SO}_{2}$ plume (fumigation), (2) chemically characterising (25 PM components) of TSP-size fractions, and diurnal and nocturnal PM10 and PM2.5 samples, and (3) in measuring the PM mass size distribution. This PM characterisation was undertaken in ambient air, during fumigations of the ${SO}_{2}$ plume on the ground and around other local PM sources. PM1 was found to be the best parameter for monitoring PM pollution derived from the ${SO}_{2}$ emissions owing to the formation of ammonium–sulphate in the finest PM fractions. Three PM1 & PM2.5 events were recorded during the field measurement campaign: two events were caused by ammonium–sulphate episodes, the third was due to an African dust outbreak. PM-mass size distribution and the high correlation of PM1 with ${SO}_{2}$ during the ${SO}_{2}$ fumigation events suggest that a significant fraction of sulphate is formed by means of `new particle formation' processes (nucleation). PM10 presents a much higher variability (noise) than PM1 & PM2.5 owing to the re-suspension of coarse (2.5– $10 μ m$ ) mineral dust particles. The PM1 load in PM10 undergoes significant variations: 60–80% during plume fumigations, 20–60% in ambient air, and down to 10% in areas affected by mineral dust re-suspension. The daily cycles observed in some PM components (sulphate, nitrate and mineral dust elements) and the chemical features of PM are also described in detail.