Table 4.
Linear models for effect of 10-min exposure measures on respiratory function, by stress group.a
| Exposure, respiratory measure | β-Value (p-value) |
p-Value for interactionb | |
|---|---|---|---|
| Stressed | Nonstressed | ||
| PM2.5 mass (μg/m3) | |||
| Frequency | 14.0 × 10−3 (0.001) | −0.41 × 10−3 (0.92) | 0.01 |
| TI | −30.0 × 10−6 (< 0.0001) | −1.71 × 10−6 (0.69) | < 0.0001 |
| TE | −5.0 × 10−5 (< 0.0001) | 0.29 × 10−5 (0.73) | < 0.0001 |
| PIF | −1.9 × 10−3 (0.17) | 3.0 × 10−3 (0.03) | 0.01 |
| PEF | −3.9 × 10−3 (0.003) | 0.13 × 10−3 (0.92) | 0.03 |
| TV | −7.3 × 10−4 (0.0001) | 0.51 × 10−4 (0.79) | 0.004 |
| MV | −0.040 (0.06) | 0.042 (0.05) | 0.007 |
| BC (μg/m3) | |||
| Frequency | 5.4 × 10−4 (0.0003) | 0.6 × 10−4 (0.68) | 0.02 |
| TI | −1.0 × 10−6 (< 0.0001) | −0.17 × 10−6 (< 0.0001) | < 0.0001 |
| TE | −0.16 × 10−7 (< 0.0001) | 0.636 × 10−7 (< 0.0001) | < 0.0001 |
| PIF | 6.0 × 10−5 (0.22) | 8.3 × 10−5 (0.10) | 0.04 |
| PEF | −14.0 × 10−5 (0.003) | 4.0 × 10−5 (0.42) | 0.12 |
| TV | −2.0 × 10−5 (0.0007) | −0.33 × 10−5 (0.64) | 0.04 |
| MV | −13.0 × 10−4 (0.096) | 9.26 × 10−4 (0.22) | 0.04 |
| PM count (no./cm3) | |||
| Frequency | 15.0 × 10−2 (0.19) | −0.97 × 10−2 (0.93) | 0.32 |
| TI | −7.4 × 10−4 (< 0.0001) | −1.6 × 10−4 (0.18) | 0.0006 |
| TE | −10.0 × 10−4 (< 0.0001) | 0.4 × 10−4 (0.86) | 0.004 |
| PIF | −0.05 (0.18) | 0.12 (0.002) | 0.001 |
| PEF | −0.115 (0.002) | 0.019 (0.61) | 0.009 |
| TV | −0.014 (0.006) | −0.005 (0.38) | 0.20 |
| MV | −1.09 (0.07) | 1.60 (0.07) | 0.001 |
a
Models were adjusted for continuous animal age and cumulative stress exposure in weeks, at each CAPs/FA exposure.
b
The p-value for interaction is derived from Equation 2 and refers to the significance for the difference in CAPs response (per μg/m3) by stress group.