ASHRAE Journal - September 2022 - 18

TECHNICAL FEATURE
FIGURE 2 (Left) Floor plan of the measurement setup. (Right) Picture of the measurement setup.
shown in Figures 3 and 4.
Figure 3 presents the PM2.5 concenStove
/ Grill
6.6 ft
0.8 ft
PM2.5 Sensor Type II
PM2.5 Sensors
side of the tube was attached to the collar of the chef, to
measure air representative for the breathing zone of the
chef. A measurement interval of 1 second was applied.
The measurement started at the same time as the cooking
and ended when background concentrations were at
baseline level. The duration of the measurement period,
therefore, varied between the different measurements.
The measurement interval for the measurements at
0.8 ft (0.25 m) and 6.6 ft (2.0 m) was 10 seconds. The
type II sensors at these locations were placed at a height
of 5.4 ft (1.65 m), assumed representative for the breathing
height.
The measured concentrations during the different
cooking techniques, hoods and settings of the hood were
compared with the WHO limit of 25 µg/m3 (limit value
for average daily PM2.5 exposure) and the WELL building
standard limit for commercial kitchens of 35 µg/m3 as
FIGURE 3 PM2.5 concentrations in the breathing zone of the chef.
Hamburgers C1
Pancakes C1
1000
100
Chinese Wok C1
trations in the breathing zone of the
chef with the canopy hoods operating
at a " high setting " with a variety
of different cooking techniques. It
can be observed that during cooking,
the PM2.5 concentrations in the
breathing zone exceeded the WHO
limit of 25 µg/m3 23% of the time.
Figure 4 shows the PM2.5 concentrations
measured close to the stove/
grill. The concentrations are compared
to the WHO daily exposure
limit and also to the guideline of
the WELL building standard for commercial kitchens
(35 µg/m3). It can be observed from Figure 4 that in
the " ideal situation, " both at a horizontal distance of
0.8 ft (0.25 m) and of 6.6 ft (2.0 m), the concentrations
exceeded the reference values less than 1% of the cooking
time.
Figure 5 presents results for a broad variety of cooking
WHO Limit Daily Average
Exposure 25 µg/m3
10
1
Time From Start Of Preparation Of Meal (Seconds)
18
ASHRAE JOURNAL ashrae.o rg S E P T E M B E R 2 0 2 2
processes, tested with the " high " and " low " setting of the
canopy hood (C1 and C2, respectively). In comparing the
different cooking styles, it can be observed that cooking
pancakes resulted in the highest PM2.5 concentrations in
the breathing zone for both ventilation settings. During
the high ventilation setting (C1), the median concentration
in the breathing zone during frying pancakes was
24 µg/m3, while it was 12 µg/m3 during broiling hamburgers
and 7 µg/m3 during stir frying. The median PM2.5
concentration for the pancakes during
the low setting (C2) was 49 µg/m3.
For the same ventilation settings, the
median value during the hamburgers
was 31 µg/m3 and 10 µg/m3 during the
Chinese style wok.
Notably, the hamburgers resulted
in the highest PM2.5 concentration at
a distance of 0.8 ft (0.25 m) and 6.6 ft
(2.0 m) from the stove/grill. At a distance
of 0.8 ft (0.25 m), the median
during the preparation of the hamburgers
was 34 µg/m3, while it was
only 8 µg/m3 and 6 µg/m3 during
the frying process of the pancakes
(pan fried) and Chinese style wok,
Hamburgers B1
PM2.5 Concentration Breathing Zone Chef [µg/m3]
60
180
240
420
540
660
120
240
360
480
600
720
840
960
120
240
360
480
600
720
840
960
120
240
360
480
540
660
780
Type I
Type II
Type II

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ASHRAE Journal - September 2022

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