Resumen
The analysis of PM10 levels in two sites of the city of San José (Catedral Metropolitana and Junta de Educación), in a period of 2.5 years (April 2004-October 2006), reported a median of 39 ± 8 and 27 ± 8 µg m-3, respectively. In addition, SO42-, NO3- and Cl- levels were measured in both areas, where annual averages resulted not significantly different between each other. The analysis of main components, applied to the collected data, reveals a 65% of total variance explained by two factors. The PC1 correlates Cl- concentration and wind speed, indicating a marine contribution to this ion. The PC2 shows a relation between SO42-, NO3- and PM10 levels, demonstrating its anthropogenic origin.