Table 4

Correlation analysis of indoor PM2.5 level with outdoor PM2.5 level, ASD and OD

Spearman correlationPartial correlation analysis
ρp Valueρp ValueControl variables
Outdoor PM2.5 level0.58<0.0010.37<0.001ASD, OD
 ASD0.52<0.0010.34<0.001Outdoor PM2.5 level, OD
 OD0.33<0.001−0.050.352Outdoor PM2.5 level, ASD
  • ASD, active smoker density, number of smokers per 100 m3; OD, occupant density, number of occupants per 100 m3.