『Abstract
PM2.5 and PM10 samples were collected in the urban atmosphere
of Elche (southeastern Spain) between December 2004 and November
2005. The samples were analyzed for mass and water-soluble inorganic
ions (Na+, NH4+, K+,
Ca2+, Mg2+, Cl-, NO3-
and SO42-) with the aim of investigating
the influence of the climatic and geographic features of a coastal
semiarid area on the contribution of these species to PM levels.
Secondary inorganic ions (SO42-,
NO3-, NH4+)
were the major components in the fine fraction (PM2.5), accounting
for 40% of the total mass. The relationship between non-marine
SO42-, and NH4+
indicated that fine sulfate particles were completely neutralized
by ammonium. In the coarse fraction (PM10-2.5), nitrate (as NaNO3 and Ca(NO3)2),
together with crustal (CaCO3) and marine
species (NaCl) accounted for almost 50% of the total mass. Fine
sulfate and coarse nitrate showed summer maximums. In contrast,
the concentrations of fine NO3-
were lowest in the warm period. ammonium presented both winter
and summer maximums. The levels of marine ions, except for coarse
Cl-, were highest in summer when the dominant wind
flow is from the sea. No significant seasonal variations were
observed of coarse Ca2+ and SO42-.
The concentrations of all inorganic ions increased during Saharan
dust events, in particular, fine NH4+
and SO42- and coarse NO3-.
Coarse calcium was proved not to be a good tracer for this type
of episode in our region since the average levels of this cation
are elevated and the relative increase in its concentrations during
African events was not as high as expected.
Keywords: Aerosols; PM2.5; PM10-2.5; Inorganic ions; Saharan dust
intrusions』
1. Introduction
2. Methodology
2.1. Description of the study zone
2.2. Sample collection and ion analysis
2.3. Meteorological analysis
3. Results and discussion
3.1. Average concentrations
3.2. Interspecies correlation
3.3. Seasonal evolution
3.4. Influence of Saharan dust intrusions
4. Conclusions
Acknowledgments
References