Table 2.

Spearman’s correlations among extracted factors, common air pollutants and some micro-meteorological parameters. Only correlations significant at p < 0.001 are shown; ρ > 0.6 are bold faced 0.35<ρ < 0.6 are in italic.

Factors	CO	NO	NO2	NOx	O3	OX	SO2	BC	PM2.5	Wind speed	Air temp.	Solar irr.
Factor 1: Nucleation		0.37			0.31	0.41	0.33			0.20	0.52	0.47
Factor 2: Traffic	0.25		0.44	0.41	−0.43	−0.31	−0.23	0.41	0.19	−0.23	−0.22
Factor 3: Airport	0.31	0.19						0.20
Factor 4: Nighttime nitrate	0.31		0.37	0.33	−0.53	−0.47	−0.43	0.64	0.48	−0.54	−0.30	−0.17
Factor 5: Regional pollution	0.52				−0.30	−0.31	−0.39	0.29	0.41	−0.23	−0.33	−0.25
Factor 6: Local resuspension			0.24	0.20	−0.55	−0.50	−0.35	0.30	0.33	−0.45	−0.54	−0.47