Table 2.

Preintervention to postintervention mean changes [95% confidence interval (CI)]^a within arm and within intervention, relative to placebo ($n=114$ participants).

Outcome	Observations	Within group change		Placebo	Change relative to placebo
		Woodstove changeout	Air filter		Woodstove changeout	Air Filter
PAQLQ
Overall	422	0.47 (0.04, 0.90)	0.22 ($-0.07$, 0.52)	0.29 (0.01, 0.58)	0.18 ($-0.33$, 0.69)	$-0.07$ ($-0.47$, 0.34)
Symptoms	422	0.61 (0.13, 1.1)	0.19 ($-0.14$, 0.52)	0.23 ($-0.09$, 0.55)	0.38 ($-0.19$, 0.95)	$-0.04$ ($-0.49$, 0.41)
Limitation of Activity	422	0.61 (0.09, 1.1)	0.23 ($-0.12$, 0.59)	0.48 (0.13, 0.82)	0.13 ($-0.48$, 0.74)	$-0.24$ ($-0.73$, 0.24)
Emotion	422	0.18 ($-0.25$, 0.61)	0.24 ($-0.06$, 0.53)	0.28 ($-0.01$, 0.56)	$-0.10$ ($-0.61$, 0.41)	$-0.04$ ($-0.44$, 0.36)
Two-week spirometry monitoring
Evening ${\text{FEV}}_1$ % predicted	406	$-0.09$ ($-8.7$, 8.5)	$-2.7$ ($-8.7$, 3.1)	$-3.0$ ($-8.7$, 2.6)	2.9 ($-7.3$, 13)	0.24 ($-7.8$, 8.3)
Morning ${\text{FEV}}_1$ % predicted	408	0.96 ($-7.8$, 9.8)	$-3.4$ ($-9.4$, 2.7)	$-2.6$ ($-8.4$, 3.1)	3.6 ($-6.8$, 14)	$-0.71$ ($-8.9$, 7.5)
Evening PEF % predicted	407	0.07 ($-7.9$, 8.0)	$-4.6$ ($-10$, 0.98)	$-7.0$ ($-12$, $-1.7$)	7.1 ($-2.3$, 16)	2.4 ($-5.0$, 9.9)
Morning PEF % predicted	409	1.1 ($-6.9$, 9.2)	$-3.3$ ($-8.9$, 2.3)	$-6.7$ ($-12$, $-1.4$)	7.8 ($-1.6$, 17)	3.4 ($-4.1$, 11)
Diurnal PEF variability, %	404	$-0.8$ ($-4.7$, 3.0)	$-2.0$ ($-4.7$, 0.7)	2.2 ($-0.4$, 4.7)	$-3.0$ ($-7.6$, 1.6)	$-4.1$ ($-7.8$, $-0.4$)

Note: ${\text{FEV}}_1$, forced expiratory volume in the first second; PAQLQ, pediatric asthma quality of life; PEF, peak expiratory flow.

^aAdjusted for age and gender.