Table 3.

Intervention effect on diurnal peak flow variability according to baseline asthma severity, relative to placebo, adjusted for age and gender.

	Participant number	Observations	Woodstove changeout	Air filter
			Mean change (95% CI)	Mean change (95% CI)
All participants	114	404	$-3.0$ ($-7.6$, 1.6)	$-4.1$ ($-7.8$, $-0.4$)
Severe	50	170	$-1.4$ ($-9.3$, 6.4)	$-4.7$ ($-12$, 2.6)
Moderate	51	190	$-5.3$ ($-14$, 3.3)	$-3.8$ ($-9.2$, 1.6)
Intermittent/mild	13	44	0.07 ($-10$, 10)	$-1.4$ ($-9.4$, 10)