Table 4.

Estimates of fixed effects of fire use characteristics in households having fire events during last 24 hours, Butajira, Ethiopia, 2000-2002 (n = 3849)

					95% Confidence Interval of slope
Indoor Fire use characteristics	Parameter Estimate (Slope)	Std. Error	T	p-value	Lower Bound	Upper Bound
Intercept	1.806	0.034	53.48	p < 0.0001	1.740	1.872
Ecology
Highland	0.189	0.012	15.75	p < 0.0001	0.165	0.212
Lowland	†
Season
Dry	-0.030	0.009	-3.33	p < 0.001	-0.048	-0.012
Wet	†
Biomass fuel type
Only wood	-0.019	0.025	-0.79	0.432	-0.067	0.029
Only Crop residues	-0.048	0.024	-1.98	0.047	-0.096	-0.001
Only dung	†
Purpose of fire events
Cooking	0.026	0.016	1.65	0.098	-0.005	0.057
Heating	-0.029	0.016	-1.87	0.061	-0.060	0.001
Insect repellent	†
Frequency of fire events
One time per day	-0.146	0.032	-4.52	p < 0.0001	-0.209	-0.083
Two times per day	-0.00001	0.019	-0.001	0.999	-0.038	0.038
Three times per day	0.020	0.017	1.16	0.247	-0.014	0.054
Four times per day	†
Frequency of food items
One food item	-0.068	0.021	-3.32	p < 0.001	-0.109	-0.028
Two food items	-0.093	0.015	-6.39	p < 0.0001	-0.122	-0.065
Three food items	-0.050	0.012	-4.09	p < 0.0001	-0.074	-0.026
Four food items	†
Highland * Dry season	-0.066	0.012	-5.39	p < 0.0001	-0.090	-0.042
Highland * wet season	†

Dependent Variable: indoor concentration in linear scale transformed to log 10; †: Reference group