Table 3.

Correlation (Spearman’s correlation coefficients.) of total PM_2.5 with source-specific PM_2.5 and elements at central sites in three cities.

	Source-specific PM2.5						Elements of PM2.5
	Traffic	LRT	Oil	Industry	Crustal	Salt	ABS	S	V	Zn	Ca	Cl	Fe	Cu
PM2.5
Amsterdam (n = 223)	0.50	0.62	0.18	0.27	−0.15	0.04	0.73	0.84	0.27	0.81	0.04	0.14	0.68	0.63
Erfurt (n = 156)	0.32	0.57	NA	0.41	0.19	NA	0.81	0.85	NA	0.82	0.51	0.63	0.81	0.70
Helsinki (n = 164)	0.26	0.82	0.35	NA	−0.01	0.19	0.70	0.85	0.59	0.77	0.17	−0.03	0.38	0.42

Abbreviations: NA, not available; LRT, long-range transported.