Table 1.

Home characteristics and their prevalence (n=777 homes)

Home characteristics	Categories	na	(%)b
Group 1(direct sources/factors or carriers of allergens)
Mold classification	0	336	43.3
	1	403	51.9
	2	37	4.8
Appearance of cockroach	Yes	89	11.5
	No	688	88.5
Number of cats	0	607	80.3
	1	76	10.0
	≥2	73	9.7
Number of dogs	0	521	68.9
	1	179	23.7
	≥2	56	7.4
Number of residents	≤4	529	68.1
	>4	248	31.9
Number of stuffed toys in PARc	0	325	42.3
	≥1	443	57.7
Number of indoor plants in PARc	0	564	74.2
	≥1	196	25.8
Relative humidity in PAR (%)	<30	109	14.0
	30–50	587	75.6
	≥50	81	10.4
Temperature in PARc (°F)	<75	433	55.7
	≥75	344	44.3
Season of dust sample collection	Spring	133	17.1
	Summer	240	30.9
	Fall	271	34.9
	Winter	133	17.1
Group 2(indirect sources or control factors of allergens)
Insect extermination	Yes	263	33.9
	No	514	66.1
Distance of PAR from kitchen (ft)	≤14	308	47.1
	>14	346	52.9
Clothes dryer vented in living quarter	Yes	15	1.9
	No	762	98.1
Humidifier use	Yes	444	57.4
	No	329	42.6
Dehumidifier use	Yes	127	16.6
	No	639	83.4
Floor material in PARc	Carpet or area rug	709	91.2
	No carpet/area rug	68	8.8
Vacuuming frequency	≤once/week	286	36.8
	2 times/week–once/day	371	47.8
	≥once/day	120	15.4
Vacuum type	Standard HEPA	474	69.1
		212	30.9
Group 3 (general housing characteristics)
Area of homes (ft2)	<1000	162	20.8
	1000–2000	270	34.8
	2000–3000	181	23.3
	3000–4000	106	13.6
	≥4000	58	7.5
Age of homes (year)	≤50	195	25.1
	>50	582	74.9
Building type	Apartment	164	21.7
	Attached house or row house	52	6.9
	Detached house	541	71.4
Location of PARc	Busy roomd	705	90.7
	Bedroom	72	9.3
Floor level of PARc	0	21	2.7
	1	645	83.9
	≥2	103	13.4
Heating method	Forced air heating only	391	50.3
	Others	386	49.7
Air circulation method	Windows open	171	22.1
	A/C unit only	603	77.9
Dust amount per unit sampling area (g/m2)e	≤0.3	388	49.9
	>0.3	389	50.1

^an: The number of homes with a particular characteristic. Numbers do not add up to 777 due to missing data.

^bPercentages were calculated with available data and add up to 100.

^cPAR: Primary activity room.

^dBusy room: living room, family room, kitchen, and dining room.

^eNot included in the regression analysis.