Cochrane-Orcutt log-linear regression analysis results for predictors of total inward leakage (TIL)
| Variable | Coefficient for TIL increase | 95% CI | P values |
| Mask | |||
| 3M9322 | reference | – | – |
| 3M9502 | 2.0 | 1.2 to 3.3 | 0.007 |
| Yimeijian | 13.9 | 8.5 to 22.7 | <0.001 |
| Yi Jie PM2.5 | 26.7 | 16.4 to 43.5 | <0.001 |
| Activity | |||
| Talking | reference | – | – |
| Breathing deeply | 1.0 | 0.9 to 1.2 | 0.812 |
| Stationary | 1.1 | 0.9 to 1.2 | 0.329 |
| Bending | 1.1 | 1.0 to 1.3 | 0.014 |
| Head moving | 1.2 | 1.1 to 1.3 | 0.001 |
| Constant n = 2084 , R2= 0.11 | 2.3 | 1.6 to 3.3 | <0.001 |
The coefficients represent the factor by which TIL is increased compared with the reference category.