. 2015 Sep 23;10(9):e0138559. doi: 10.1371/journal.pone.0138559

Table 2. Pearson correlation between indoor and ambient PM_2.5 mass concentrations.

	24-h period	Morning (6:00–12:00)	Afternoon (12:00–18:00)	Evening (18:00–0:00)	Night (0:00–6:00)
Including all families
Coefficient	0.91	0.92	0.90	0.92	0.92
p-value	<0.0001
Excluding smoking families
Coefficient	0.92	0.92	0.90	0.94	0.93
p-value	<0.0001

Table 2. Pearson correlation between indoor and ambient PM2.5 mass concentrations.