Table 2.

Associations between meteorological or house physical factors and particle infiltration ratio in univariate mixed effect model

Variable	N	Coefficient estimate	Standard error	p-value
Meteorological Factors
Outdoor Temperature (°C)	810	−0.009	0.001	<0.0001
Indoor Temperature (°C)	749	−0.022	0.006	<0.0001
Relative humidity (%)	810	−0.001	0.001	0.236
Indoor Relative humidity (%)	749	−0.004	0.002	0.011
Wind speed (m/s)	810	0.013	0.008	0.080
Precipitation (inch/day)	810	0.027	0.027	0.319
House Physical Factors
House Age	810	0.0003	0.001	0.828
Square Footage (per 100 sq.ft)	810	−0.002	0.004	0.485
Number of Windows	810	0.126	0.071	0.149