Table 1.

Soluble metals analysis on PM filters^a

Metal	PFP soluble metals (μg metal/g PM)	Fresno soluble metals (μg metal/g PM)b
Co	< 3.2	n/a
Cr	< 0.84	n/a
Cu	< 1.0	344 ± 137
Fe	< 25	262 ± 32
Mn	< 1.8	397 ± 56
Ni	< 3.4	n/a
V	< 0.68	17 ± 3
Zn	7.8 ± 4.9	n/a

n/a indicates data that are not available. Measurements are the average ± standard deviation.

^a) Filter blank corrected soluble concentrations of 8 common transition metals were measured in PFP samples, an urban PM_2.5 sample from Fresno, CA. Only zinc (Zn) was detected above background levels in the PFP samples.

^b) from Shen et al., [30].

^c) "< value" indicates a result less than the limit of quantification (10 × SD of the blank).