Residential cooking and use of kitchen ventilation: The impact on exposure

Figures & data

Table 1. General description of the sampling homes

Characteristics		City		Total
		Halifax	Edmonton
Number of homes		58	74	132
Dwelling type	Detached house	53	69	122
	Row house	0	4	4
	Duplex/triplex	2	1	3
	Other	3	0	3
Year of construction	1940 and before	12	10	22
	1941–1960	13	21	34
	1961–1980	10	13	23
	1981–2000	10	15	25
	2001–2012	13	15	28
Home size (ft^2)	<1000	1	1	2
	1000–2000	22	14	36
	2000–3000	23	35	58
	≥3000	11	20	31
	Unknown	1	4	5
Cooktop fuel type	Electric	45	58	103
	Gas	13	16	29
Range hood ventilation type	Vented	35	39	73
	Unvented	15	13	29
	Unknown	0	6	6
	None	8	16	24
Number of residents	1– 2	25	32	57
	3– 4	28	34	62
	5 or more	5	8	13
Homeowner educational level	Elementary	1	0	1
	High School	3	4	7
	Technical college	11	20	31
	University	38	49	87
	Other	5	1	6
Total household income (Canadian dollars)	< 35,000	5	1	6
	35,000– 80,000	18	18	36
	≥ 80,000	32	48	80
	Prefer not to say	3	6	9
	Do not know	0	1	1

Table 2. Number and percentage of indoor cooking activities by influential factors

Factor	Group	Cooking activities
		N	%
Season	Winter	1562	57
	Summer	1186	43
Weekday vs. weekend^†	Weekend	419	52
	Weekday	382	48
Mealtime	Dinner	1138	41
	Breakfast	952	35
	Lunch	658	24
Cooking method/device	Toaster toasting	786	29
	Stove frying	504	18
	Stove boiling	437	16
	Oven baking	436	16
	Stove sautéing	246	9
	Toaster oven toasting	142	5
	Oven broiling	58	2
	Stove grilling	41	1
	Toaster oven baking	39	1
	Oven grilling	34	1
	Toaster oven broiling	19	0.7
	Toaster oven grilling	6	0.3

Notes. ^†Numbers shown are per day.

Table 3. Duration of cooking activities by influential factors

Factor	Group	Duration of cooking (minute)
		N	GM (GSD)	95% CI	IQR	Letter group^†
Mealtime	Dinner	1138	18 (2.5)	17– 19	10– 30	A
	Lunch	658	13 (3.1)	12– 14	5.0– 25	B
	Breakfast	952	5.4 (2.7)	5.1– 5.8	3.0– 10	C
Weekday vs. weekend	Weekend	838	12 (3.1)	11– 13	5.0– 30	A
	Weekday	1910	10 (3.1)	9.9– 11	5.0– 25	B
Cooking method/ device	Oven baking	436	41 (1.9)	38– 44	25– 60	A
	Toaster oven baking	39	23 (2.0)	19– 29	15– 30	BC
	Oven grilling	34	23 (2.7)	16– 32	15– 45	B
	Toaster oven broiling	19	17 (2.0)	12– 24	12– 30	BCD
	Stove sautéing	246	17 (2.1)	15– 18	10– 30	BCD
	Toaster oven grilling	6	15 (2.4)	6.1– 39	10– 30	BCD
	Oven broiling	58	15 (2.4)	12– 19	10– 25	BCD
	Stove boiling	437	15 (2.1)	14– 16	10– 20	BCD
	Stove frying	504	14 (2.1)	13– 15	10– 24	CD
	Stove grilling	41	12 (2.1)	9.1– 15	10– 20	D
	Toaster oven toasting	142	4.7 (1.9)	4.3– 5.2	3.0– 6.0	E
	Toaster toasting	786	3.3 (2.0)	3.2– 3.5	2.0– 5.0	F

Notes. ^† For each factor, group geometric means with the same letter are not significantly different from each other (p > 0.05), based on Tukey-Kramer multiple comparison test.

Figure 1. Ventilation conditions during cooking or within 15 minutes after cooking ended, by season

Figure 2. The timing of turning on and off a range hood due to cooking

Figure 3. The timing of opening and closing the windows related to cooking episodes

Table 4. Estimated PM_2.5 decay rates by ventilation condition

Ventilation condition	Decay rate (h^−1)
	N	GM (GSD)	95% CI	IQR	Letter group
Kitchen window(s)	26	2.7 (2.0)	2.0– 3.5	1.7– 4.6	A
Range hood + any window(s)^†	10	2.5 (2.0)	1.6– 4.1	2.0– 3.5	A
Range hood	16	2.3 (1.7)	1.7– 3.0	1.7– 3.2	A
Other window(s)	39	1.3 (2.1)	1.0– 1.7	0.71– 2.0	B
All windows closed + range hood off	156	1.1 (1.8)	1.0– 1.2	0.76– 1.7	B

Notes. ^†N(kitchen windows open) = 2, N(other windows open) =8.

Table 5. Estimated PM_2.5 decay rates by home construction year, under the condition of no range hood use and all windows closed

Home construction year	Decay rate (h^−1)
	N	GM (GSD)	95% CI	IQR	Letter group
1940 and before	23	1.5 (1.6)	1.2– 1.8	1.0– 2.4	A
1941–1960	29	1.1 (1.9)	0.86– 1.4	0.77– 1.9	AB
1961–1980	49	1.0 (1.8)	0.88– 1.2	0.71– 1.7	AB
1981–2000	21	1.2 (1.5)	1.0– 1.5	0.92– 1.6	AB
2001–2012	34	0.9 (1.8)	0.74– 1.1	0.69– 1.4	B

Table 6. Estimated PM_2.5 source strengths and emission masses by cooktop fuel type and cooking method/device

Cooking method/device^†	Fuel type^‡	N	Source strength (mg min^−1)		Emission mass (mg)		Letter group
			GM (GSD)	IQR	GM (GSD)	IQR
Total	G	42	1.3 (4.2)	0.36– 4.2	17 (4.1)	5.9– 51	A
	E	180	0.64 (5.0)	0.23– 1.9	8.0 (3.7)	2.7– 20	B
Stove frying	G	22	1.8 (4.9)	0.49– 4.2	20 (3.5)	9.3– 48	A
	E	72	0.8 (4.1)	0.29– 2.1	8.3 (4.0)	2.4– 22	B
Stove grilling	G	1	12 (–)	–	–	–	–
	E	11	1.1 (4.0)	0.39– 3.5	12 (3.6)	3.7– 33	–
Stove sautéing	G	3	1.3 (4.3)	0.36– 6.4	18 (4.2)	4.3– 77	A
	E	21	0.91 (4.2)	0.23– 2.3	10 (3.1)	4.2– 21	A
Stove boiling	G	3	0.35 (2.9)	0.11– 0.84	3.3 (1.9)	1.6– 5.4	A
	E	13	0.22 (3.2)	0.13– 0.45	2.9 (3.1)	1.3– 4.3	A
Oven baking	G	7	0.67 (6.9)	0.12– 5.7	17 (5.9)	3.8– 159	A
	E	39	0.40 (4.3)	0.14– 1.1	7.1 (3.9)	2.6– 19	A
Oven broiling	G	0	–	–	–	–	–
	E	3	0.32 (4.8)	0.09– 1.9	2.4 (2.4)	0.9– 4.6	–
Oven grilling	G	2	0.24 (2.1)	0.14– 0.4	5.1 (2.3)	2.9– 9	A
	E	9	0.71 (2.3)	0.37– 1.9	10 (2.3)	5.7– 16	A
Multiple	G	4	2.1 (2.5)	1.1– 4.3	27 (3.1)	2.6– 21	A
	E	12	0.88 (4.6)	0.51– 2.0	9.8 (3.7)	10– 70	A

Notes. ^†Cooking devices using electricity only (toaster and toaster oven) were excluded.

^‡G = Gas, E = Electric.

Table 7. Exposure estimates for a person in the living or family room to PM_2.5 due to cooking

Exposure period		Exposure estimate (µg m^−3 h)
		N	GM (GSD)	95% CI	IQR
During cooking		391	3.4 (4.7)	2.9– 3.9	1.0– 12
After cooking	1 hr	391	6.2 (9.2)	5.0– 7.8	1.5– 35
	2 hrs	122	9.5 (4.6)	7.2– 12	3.2– 30
	3 hrs	46	9.7 (4.2)	6.3– 15	4.9– 29
	4 hrs	23	6.4 (2.7)	4.1– 9.8	2.8– 13
	> 4 hrs	4	3.6 (6.5)	0.18– 70	3.5– 10
Whole cooking event		391	12 (6.6)	9.9– 14	3.0– 55