Source apportionment of ambient PM_(2.5) at five Spanish centres of the european community respiratory health survey (ECRHS II)

摘要

Fine particulate matter (PM_(2.5)) was sampled at 5 Spanish locations during the European Community Respiratory Health Survey II (ECRHS II). In an attempt to identify and quantify PM_(2.5) sources, source contribution analysis by principal component analysis (PCA) was performed on five datasets containing elemental composition of PM_(2.5) analysed by ED-XRF. A total of 4-5 factors were identified at each site, three of them being common to all sites (interpreted as traffic, mineral and secondary aerosols) whereas industrial sources were site-specific. Sea-salt was identified as independent source at all coastal locations except for Barcelona (where it was clustered with secondary aerosols). Despite their typically dominant coarse grain-size distribution, mineral and marine aerosols were clearly observed in PM_(2.5). Multi-linear regression analysis (MLRA) was applied to the data, showing that traffic was the main source of PM_(2.5) at the five sites (39-53% of PM_(2.5), 5.1-12.0 μgm~(-3)), while regional-scale secondary aerosols accounted for 14-34% of PM_(2.5) (2.6-4.5μgm~(-3)), mineral matter for 13-31% (2.4—4.6μgm~(-3)) and sea-salt made up 3-7% of the PM_(2.5) mass (0.4-1.3 μgm~(-3)). Consequently, despite regional and climatic variability throughout Spain, the same four main PM_(2.5) emission sources were identified at all the study sites and the differences between the relative contributions of each of these sources varied at most 20%. This would corroborate PM_(2.5) as a useful parameter for health studies and environmental policy-making, owing to the fact that it is not as subject to the influence of micro-sitting as other parameters such as PM_(10). African dust inputs were observed in the mineral source, adding on average 4-11 μgm~(-3) to the PM_(2.5) daily mean duringrndust outbreaks. On average, levels of Al, Si, Ti and Fe during African episodes were higher by a factor of 2-8 with respect to non-African days, whereas levels of local pollutants (absorption coefficient, S, Pb, Cl) showed smaller variations (factor of 0.5-2).