Exposure to airborne ultrafine particles from cooking in Portuguese homes

Figures & data

Figure 1. Layout of the residential kitchen.

Figure 2. Location of sampling probe.

Figure 3. Aspect of gas stove showing used stations for cooking.

Figure 4. Schematic showing the operation principle of a NSAM equipment (TSI, 2005).

Table 1. Measurement results

Samplingconditions	Average deposited area (μm^2/cm^3)	TWA for 8 hr(μm^2/cm^3)	Total deposited area(μm^2)	Dose per lung area(μm^2/m^2) ^a
Baseline	73 ± 7.4	1.3	6.07 × 10^5	7.59 × 10^3
Boiling cauliflower	230 ± 9.9	9.6	4.60 × 10^6	5.75 × 10^4
Boiling fish	890 ± 38.3	37.1	1.78 × 10^7	2.23 × 10^5
Frying sauce	388 ± 8.3	11.2	5.37 × 10^6	6.71 × 10^4
Boiling broccoli	175 ± 7.5	13.0	6.26 × 10^6	7.83 × 10^4
Frying hamburger	100 ± 4.3	20.5	9.86 × 10^6	1.23 × 10^5
Frying egg	230 ± 10.2
Boiling spaghetti	120 ± 5.2	8.2	3.94 × 10^6	4.92 × 10^4
Total for meal preparation	—	18.8	4.78 × 10^7	5.98 × 10^5
Total for meal preparation discounting baseline	—	18.3	4.72 × 10^7	5.90 × 10^5
Note: ^aConsidering an average lung area of 80 m^2.

Figure 5. Measurements during baseline showing the evolution of alveolar deposited surface area (ADSA) with time: sample 1 (no cooking, no gas flame); sample 2 (no cooking but gas flame on station 3); sample 3 (no cooking but gas flame on station 1).

Figure 6. Measurements during cauliflower boiling with cooking events marked, showing the evolution of ADSA with time (indicators are described in Table 3).

Table 2. Baseline determination

	No cooking, no gas burning	No cooking, gas burning in station 3	No cooking, gas burning in station 1
Average deposited area (μm^2/cm^3)	42.7 ± 0.25	46.2 ± 4.39	72.9 ± 7.44
Minimum measured value (μm^2/cm^3)	42.1	42.3	60.5
Maximum measured value (μm^2/cm^3)	43.3	59.4	85.5
TWA for 8 hr(μm^2/cm^3)	0.98	0.91	1.27
Total deposited area(μm^2)	4.70 × 10^5	4.39 × 10^5	6.07 × 10^5
Dose per lung area(μm^2/m^2)*	5.88 × 10^3	5.48 × 10^3	7.59 × 10^3
*Considering an average lung area of 80 m^2.

Figure 7. Measurements during broccoli boiling with cooking events marked, showing the evolution of ADSA with time (indicators are described in Table 4).

Figure 8. Measurements during spaghetti boiling with cooking events marked, showing the evolution of ADSA with time (indicators are described in Table 5).

Figure 9. Measurements during hamburger and egg frying with cooking events marked: (a) expanded scale 0.0 to 6000 μm²/cm³; (b) reduced scale: 0.0 to 600 μm²/cm³, showing the evolution of ADSA with time (indicators are described in Table 6).

Table 3. Sequence of events during cauliflower boiling

Indicator	Time	Cooking phase: cauliflower boiling	ADSA (μm^2/cm^3)
1	18:53	Baseline	73
	18:55	Water and salt added	75
	19:00	Water starts boiling	100
2	19:02	Lid removed and cauliflower added	175
	19:03	Steam emitted entraining particles	1900
	19:04	Lid put onto saucepan	200
3	19:07	Lid partially uncovered	225
4	19:09	Lid removed	600
5	19:12	Heat turned off: cooking ready	850

Table 4. Sequence of events during broccoli boiling

Indicator	Time	Cooking phase: broccoli boiling	ADSA (μm^2/cm^3)
1	19:48	Baseline	30
	19:49	Water and salt added	35
2	19:51	Water starts boiling	70
3	19:56	Lid removed	130
4	19:57	Lid put onto saucepan	110
5	20:04	Broccoli added	190
	20:06	Broccoli boiling	240
	20:17	Broccoli boiling	310
6	20:19	Heat turned off: cooking ready	280
	20:22	After cooking emission (possible coagulation of emitted particles)	360

Table 5. Sequence of events during spaghetti boiling

Indicator	Time	Cooking phase: spaghetti boiling	ADSA (μm^2/cm^3)
	19:34	Baseline	30
	19:35	Water and salt added	35
	19:36	Water starts boiling	40
1	19:37	Spaghetti added	70
2	19:45	Spaghetti boiling	130
	19:53	Heat turned off: cooking ready	120
	19:55	Spaghetti taken out	110
3	20:00	After cooking emission (possible coagulation of emitted particles)	80

Table 6. Sequence of events during cooking of the meat dish

Indicator	Time	Cooking phase: meat dish	ADSA (μm^2/cm^3)
		Baseline	40
	16:10	Margarine and cream added	45
1	16:13	Hamburger starts to fry	45
	16:15	Hamburger frying	50
2	16:18	Hamburger cooked	100
	16:20	Heat is turned off: hamburger removed	100
3	16:51	Heat is turned on	50
	16:52	Egg starts to fry	4500
	16:54	Heat is turned off: egg cooked	110
4	16:55	Egg is removed	160
	17:00	After cooking emission (possible coagulation of emitted particles)	230
	18:00	Baseline levels reached again

Table 7. Calculated concentration recovery rate

Sampling conditions	Average deposited area (μm^2/cm^3)	Recovery time until baseline (min)	Recovery rate(μm^2/cm^3 min)
Frying hamburger	100.0	14:30	4.0
Frying egg	230.0	60:00	3.0
Boiling spaghetti	120.0	30:00	1.7