ASHRAE Journal - September 2022 - 22

TECHNICAL FEATURE
TABLE 2 Statistical comparison between PM2.5 concentration in the breathing zone of the cook using the different
hoods and the different settings of the hoods.
HOOD + AIRFLOW
SETTING
MEDIAN
(µg/m3)
Canopy, High (C1)
Backshelf, High
(B1, 2nd Part)
Canopy, High (C1)
Canopy, Low
(C2, 2nd Part)
Backshelf, High
(B1, 1st Part)
12
20
12
50
3
HOOD + AIRFLOW
SETTING
Canopy Low (C2)
Backshelf, Low
(B2 Standard)
Backshelf, High (B1)
Backshelf, Low
(B2 Standard)
Backshelf, High (B2
High Efficiency)
TABLE 3 Characteristics of the restaurants.
NO.
#1
#2
CUISINE
University Restaurant
Lunchroom (Eggs, Soup,
Sandwiches)
#3
#4
#5
#6
#7
Italian (Pasta, Fish, Meat)
Dutch (Meat, Salads, Frying,
Oven)
Irish (Hamburgers)
Asian (Wok)
Pancakes
MEAL
Dinner
Lunch
Dinner
Dinner
Dinner
Dinner
Lunch
MEDIAN (µg/m3)
31
384
6
384
4
p-VALUE
<0.001
<0.001
0.04
<0.001
0.24
SIGNIFICANT
DIFFERENCE
Yes
Yes
Yes
Yes
No
PM2.5 measurements were performed
in the breathing zone of the
chef during cooking, similar to what
was done in the lab study, at two
locations in the kitchen and outdoors.
For Restaurant 3, 4, 6 and 7,
measurements were also performed
in the restaurant itself.
TYPE OF KITCHEN
Semi-Open
Semi-Open
Open
Closed
Closed
Open
Open
FIGURE 6 Schematic of the protocol during the measurements (top); typical position of the measurements
equipment (bottom).
Time
All the measurements followed a
similar procedure. This is summarized
in Figure 6, top. In the kitchen
three PM2.5 measurement locations
were identified (Figure 6, bottom),
one near the breathing zone of the
chef (PM2.5 sensor type I; measurement
interval 1 second) and two at
approximately 3.3 ft (1.0 m) and
6.6 ft (2.0 m) from the stove (PM2.5
sensor type II; measurement interval
10 seconds). The duration of
the measurements in the kitchen
depended on the number of meals
that were being prepared, but lasted
at least 15 minutes. The measurements
in the kitchen were stopped
around 30 minutes after the last
meal was being prepared.
Outdoor
Measurement #1
Map
Characteristics
Breathing Zone, Kitchen 2x, Restaurant
PM2.5 Measurements
PM2.5
Sensors
Outdoor
Measurement #2
Stove
Results and Discussion
An example of the exposure of
the chef for Restaurant 1 over the
course of the measurement period
is presented in Figure 7. For the peaks
it is indicated what cooking activity
took place. The results show a
very irregular pattern of the PM2.5
exposure of the chef, including very
steep and high peaks. This outcome
is representative for the other restaurants.
The peak exposure can
be linked to the cooking and frying
activities taking place. This may
include the PM2.5 production of the
February 27, 2020 (Table 3). In all restaurants, measurements
were performed during one evening (dinner) or
one afternoon (lunch) when the restaurant occupancy
was representative for a typical day. At each restaurant,
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ASHRAE JOURNAL ashrae.o rg
S E PTEM B E R 2022
actual activity and the behavior of the chef at that time.
For example, the chef may position his head between
the stove and the exhaust hood. Average values for all
restaurants during the measurement period, however,
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ASHRAE Journal - September 2022

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