Seasonal evolution of suspended particles around a large coal-fired power station: particulate levels and sources

Abstract The present work focuses on the seasonal evolution of suspended particles (TSP and PM10) around the Teruel power station in NE Spain. The specific objectives are the determination of the spatial and time variability of levels of suspended particles, and their relationship with the power plant emissions and other natural or anthropogenic (local or external) particulate sources. The results show a marked seasonal trend, along the study period (July 1995–August 1996) which is characterized by particulate levels that were higher in spring–summer and decreased progressively towards winter. This trend may be related to (a) higher summer oxidation which increased levels of secondary particles, (b) higher convective circulation in summer which raised levels of soil-related particles and anthropogenic particles, (c) higher frequency of intrusion episodes of Sahara air masses in summer and spring, and (d) lower aerosol scavenging potential in summer. The similarity between the seasonal evolutions of daily mean levels of SO 2 and particulates is due to the fact that both are partially controlled by the solar cycle. The long range transport particulate inputs affecting this area of the Mediterranean Basin (mainly Sahara air mass intrusions) account for major particulate peaks recorded at the monitoring stations. The influence of the emissions from the power plant in the PM10 and TSP levels is evidenced only in periods with a low background particulate levels. The results demonstrate that even PM10 levels are still highly influenced by the Saharian and European particulate inputs. Therefore, for an accurate environmental assessment, probably PM2.5 should be monitored instead of TSP or PM10, in order to quantify the influence of the power plant emissions on the bulk atmospheric particulate levels. The results obtained from the air back-trajectory analysis and their comparison with the time series of daily PM10 levels allowed the classification of the major external particulate inputs as a function of the particulate levels.