Programme - Ação Integrada Luso-Espanhola nº E-84/07
Execution dates - 2007-01-01 - 2008-12-31 (24 Months)
Funding Entity - CRUP
Funding for CESAM - 3000 €
Proponent Institution - Universidade de Aveiro
Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Madrid
Atmospheric particulate matter (PM) plays an important role in different processes that affect to the human life. In recent years there has been an increasing interest in PM, mainly based on human health and environmental concerns (Pope et al., 2002). The recent implementation of the EU directive 1999/30/CE which establishes daily and annual limit values for PM10 (PM under 10 µm in diameter), has promoted an increasing number of numerical and experimental scientific works showing levels of PM10 in European regions. The main aim of these works was to know whether the limit values would be met and to detect those limit values exceedences produced by natural processes, such us African dust outbreaks.
Current research trends tend to focus on the finer fraction PM2.5 (PM under 2.5 µm in diameter) as a result of its higher implications on human health than the coarser fractions. This fact has led to the European Commission (Second Position Paper on Particulate Matter; CE, 2004 and draft Air Quality Directive and Clean Air for Europe from September 2005) to argue in favour of new additional limits based on PM2.5 measurements. To determine suitable PM2.5 limits, is necessary to characterize its main properties, among them the chemical composition, levels and sources.
Carbon is considered the most abundant compound in the PM2.5 fraction. The last results obtained point to a carbon content of the PM2.5 mass from 28% to 68% (Querol et al., 2004). This variability is associated to the emissions from anthropogenic sources, specific meteorological conditions and external apports. PM carbon content is mainly composed of elemental carbon (EC) and organic carbon (OC). EC is directly emitted to the atmosphere during combustion processes. OC is also directly emitted from anthropogenic and natural sources but it can be additionally produced through gas-to-particle conversion processes in the atmosphere.
The analytical determination of EC and OC levels is extremely hard. This is why there are presently a low number of published long time series of EC and OC levels. The study of these time series obtained in specific sites will allow studying the seasonal variability of the EC and OC levels as well as determining the influence of the different sources and atmospheric processes involved in their formation. The determination of these levels, in combination with the chemical composition of PM2.5, will help on developing updated emission profiles for interpret source categories in the Iberian Peninsula.