Gravimetrically obtained particulate matter concentrations for the sampling period are shown in Figure 2. The difference between the concentration using quartz and PTFE filters was significant for a few days shown in the ovals in Figure 2 due to unidentified operational errors.
La concentración del material particulado varía de manera significativa durante el periodo de muestreo Figura 2 y en algunos días de éste, la diferencia reportada entre los dos tipos de filtros es a-preciable círculos en la Figura 2.