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61 SONA 2021|The Architectural Response on Global Challenges
ASSESSMENT OF INDOOR AIR QUALITY ON KATHMANDU URBAN
KITCHENS FOR SUSTAINABILITY
○Bindu Shrestha*
1. Introduction
Household energy contributes 35% of total world energy, and it
is expected to increase by 20-40% in 2040 (Santamouris, 2019).
In the Asian context, cooking is one of the higher energy-
consuming activities within households. The kitchen is one of
the considerable spaces where women spend more time in
family food and health. In the context of Nepal, households
consume 80% of total energy with almost 60% of total energy
in cooking activities (Nakarmi, 2018). Kathmandu city accounts
for 22% of the total population (CBS, 2015) and is accompanied
by the complex urban problems of severe demand for resources
contributing to health consequences. It has a more considerable
impact on kitchen design in human health. Pandey et al. (1990)
and Pokharel & Rijal (2020) have emphasized that poor
ventilation ultimately increases CO2 concentrations resulting in
poor IAQ, and recognized building characteristics, such as
infiltration and ventilation rate, play an essential role in the
variation of indoor CO2 concentration. Besides, cooking oil,
smoking, and human activities are imperative contributors to
indoor air pollution (IAP) due to fuel emissions, people's
smoking, and cleaning home (Du & Wang, 2020). With this
consideration, this study aims to identify the linkage between
kitchen design along with the use of electric appliances (kitchen
hoods/exhaust fans) with indoor air quality in urban Kathmandu
households. Indoor air quality is one of the vital agendas for
environmental sustainability linking to human health. It is
recommended that building regulations need to consider of
energy and comfort of the kitchen workers.
2. Methods and materials
The research is designed as a case study based on a
sustainability perspective with energy linkage. The research
method approach is twofold: quantitative and qualitative
methods with field tests, questionnaire surveys, and interviews
to reveal the lived experiences, energy culture, and the
environment. The study has revealed a social reality as a
construction of people’s life. The research strategy focuses o n
ethnography and the Kathmandu case. The door-to-door
questionnaires survey have done in 623 households in
Kathmandu in three city layers – city-core, middle-city, and
outer-city. Each city layers consist of 208 households. The
environmental data – indoor air quality tests (CO2, RH, indoor
air temp.) have taken in 12 households in the three city layers.
The air quality test was done using Onset’s HOBO MX1102
CO2 sensor in the cooking areas. It has a recording range: 0 to
5000 ppm and accuracy: ±50 ppm ±5% in a non-condensing
environment. The qualitative analysis of interviews and
observation was analyzed, developed network, and
interpretation is obtained in a neutral voice relating to literature.
Table 1: Demographic data in three-city layers
3. Results and Discussions
A. Use of Kitchen hoods/exhaust fan in Urban Kitchens
The use of exhaust fans and chimneys was higher in modern
buildings compared to traditional and mixed buildings. The data
showed that 23% of modern buildings contained exhaust fans,
and 22% consisted of chimneys, while the traditional building
contained exhaust fans only 0.3% and chimneys by 0.16%.
Mixed buildings contained 2% of exhaust fans and 1% of
chimneys. The observation and findings indicated that most
Location
Ho use Ty pe Family Type Residence Type
Modern
(%)
Traditional
(%)
Mixed
(%)
Joint
(%)
Nuclear
(%)
Single
(%)
Own
(%)
Rental
(%)
Inner city 67 16 17 25 71 4 64 36
Middle city 95 1 4 14 83 3 58 42
Outer city 90 3 7 13 80 6 54 46
Abstract
In the Nepalese context, cooking is one of the most significant energy-intensive activities in households, and women contribute
higher in household chores than men, including cooking activities in the kitchen. Kitchen indoor air quality has a crucial
environmental role for dwellers. It has a strong linkage with kitchen design (building design) and health issues to achieve
sustainability. The study suggests that IAQ should be a concern of city development authorities and building-by-laws.
Keywords: Energy, indoor air quality, urban kitchen, household
*Vice-principal/Associate professor, Cosmos College of Management and Technology, Pokhara University
Referred Summary SONA International Convention 2021.10.
62
SONA 2021|The Architectural Response on Global Challenges
new buildings consisted of kitchen hoods and proper ventilation
to achieve a healthy kitchen. WHO standards and the American
Society of Conditioning Engineers (ASHRAE) have provided
ventilation standards to maintain a level of CO2 and suggested
having windows open for fresh air flow and healthy air quality.
Carbon dioxide level has potential health issues when it exceeds
1000 ppm (Fisk et al., 2013) and impacts human decision
level.
B. Air Quality on Normal days
The comparison of the CO2 concentration level in the
households could illustrate the role of ventilation and kitchen
hoods appropriately in IAQ, as shown in Figure 1.In the D12
household, cooking dinner time was higher than morning time,
and CO2 concentration raised to 1630 ppm with the only use of
LPG for cooking. The trend of average ppm remained below
1000 ppm. The kitchen did not have any exhaust fan and
chimney, but openings were located rear side of the cooking
area. The average CO2 concentration level was 523 ppm, with
a variance of 209 ppm. In the D13 household, CO2
concentration level in a day was higher in evening dinner
cooking time, raised to 2150 ppm. The cooking space did not
have ventilation, an exhaust fan, and a kitchen hood. The
average CO2 concentration was 728 ppm, with a variance of
589 ppm. The higher variance was noticed in this household, as
shown in Figure 1, due to the use of firewood/coal to make
barbeque (choyala) in the evening.
Figure 1. CO2 concentration level in urban kitchen
C. Air Quality on Social Events
Family & friends gather, and cooking varieties of food in the
social events are part of energy-consuming activities.
Kathmandu city consisted of inherent cultural and religious
beliefs. Respondent of inner-city - D12 household had less
frequency of social activities in the home and resulted in low
energy consumption. However, IAQ in terms of CO2
Figure 2. CO2 concentration level in urban kitchen during
social events
concentration level resulted higher during a social gathering,
raised to 3634 ppm due to use of firewood for making
traditional barbeque -choyala (Figure 2).
The observations showed that the household of low-income
groups living in rental spaces used fewer electrical appliances
and fewer social activities. However, those spaces had relatively
higher CO2 levels compared to household owners’ space.
D. Cooking Culture
The observation on cooking showed that it has also impacted
the energy use pattern and air quality of the kitchen. The
respondents of households D12, D13 cooked 2-3 items daily
while D8, D3, D2, & D6 cooked 4-6 six food items daily for
two-time meals. The daily energy-intensive activities were
shallow due to food habits. On the contrary, household D2
cooked a similar number, but vegetarian foods and the family
was based on religious belief and self-energy consciousness.
The result showed that health issues influenced cooking culture,
food habits, availability of cooking time, religious and cultural
aspects that ultimately influenced energy consumption to a
certain extent and influenced the IAQ of the kitchen. However,
this study could not provide enough statistical data on the
relationship.
4. Discussions
Environmentally, kitchen design and culture had been improved
due to electric kitchen hoods for better air quality. In contrast,
the air quality results showed the inner-city kitchen
environment, especially in the rental spaces lacking ventilation,
exhaust fans, and chimneys. It has been identified that time
spent in higher pollutant kitchens has significant risk factors for
acute respiratory infections. In this regard, Lee et al. (2012) and
Rahman & Islam (2016) investigated that kitchen hood system
can reduce CO2 concentration (@ 1.5 m/s hood system Vs.
close vent) by ten times by the use of an efficient hood system
to maintain thermal comfort quite well inside the kitchen space.
One of the contributing factors to an increased level of CO2 in
the Kathmandu urban kitchen was found as increased
occupancy, cooking culture, and cooking fuel types. Shen et al.
(2020) and Taneja et al. (2008) underlined that cooking
activities contributed to emitting CO2, including other
pollutants.
Additionally, the trend of increased indoor CO2 levels was
higher in winter compared to summer. In this regard, factors
included indoor activities, closed ventilation, stagnant
pollutants, and human occupancy duration played a role in
increasing CO2 concentration due to limited floor area and
human metabolism. However, information on IAQ in the
kitchens in urban households was minimal in Kathmandu. In
this study, females have long cooking hours and are exposed to
1,045
1,630
1,824
1,485
827 663
2,150
0
500
1000
1500
2000
2500
7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:000: 00
CO2 concentration (ppm)
Time (hour)
D3 D12 D8 D2 D6 D13
1,681
2,250
3,634
2,683
3,030
1,337
1,497
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
19:00 20:00 21:00 22:00 23:00
CO2 concentration (ppm)
Social event period (hour)
D6 D2 D3 D12 D8 D13
new buildings consisted of kitchen hoods and proper ventilation
to achieve a healthy kitchen. WHO standards and the American
Society of Conditioning Engineers (ASHRAE) have provided
ventilation standards to maintain a level of CO2 and suggested
having windows open for fresh air flow and healthy air quality.
Carbon dioxide level h as potential health issues when it exc eeds
1000 ppm (Fisk et al., 2013) and impacts human decision
level.
B. Air Quality on Normal days
The comparison of the C O2 concentration level in th e
households could illustrate the role of ventilation and kitchen
hoods appropriately in IAQ, as shown in Figure 1.In the D12
household, cooking dinner time was higher than morning time,
and CO2 concentration raised to 1630 ppm with the only use of
LPG for cooking. The trend of average ppm remained below
1000 ppm. The kitchen did not have any exhaust fan and
chimney, but openings were located rear side of the cooking
area. The average C O2 concentration level was 523 ppm, with
a variance of 209 ppm. In the D13 household, CO2
concentration l evel in a day was higher in evening dinner
cooking time, raised to 2150 ppm. The cooking space did not
have ventilation, an exhaust fan, and a kitchen hood. The
average CO2 concentration was 728 ppm, with a variance of
589 ppm. The higher variance was noticed in this household, as
shown in Figure 1, due to the use of firewood/coal to make
barbeque (choyala) in the evening.
Figure 1. CO2 concentration level in urban kitchen
C. Air Quality on Social Events
Family & friends gather, and cooking varieties of food in the
social events are part of energy-consuming activities.
Kathmandu city consisted of inherent cultural and religious
beliefs. Respondent of inner-city - D12 household had less
frequency of social activities in the home and resulted in low
energy consumption. However, IAQ in terms of CO2
concentration level resulted higher during a social gathering,
raised to 3634 ppm due to use of firewood for making
traditional barbeque -choyala (Figure 2).
Figure 2. CO2 concentration level in urban kitchen during
social events
The observations showed that the household of low-income
groups living in rental spaces used fewer electrical appliances
and fewer social activities. Ho wever, those spaces had relatively
higher CO2 levels compared to household owners’ space.
D. Cooking Culture
The observation on cooking showed that it has also impacted
the energy use pattern and air quality of the kit chen. The
respondents of households D12, D13 cooked 2-3 items daily
while D8, D3, D2, & D6 cooked 4-6 six food items daily for
two-time meals. The daily energy-intensive activities were
shallow due to food habit s. On the contrary, household D2
cooked a similar number, but vegetarian foods and the family
was based on religious belief and self-energy consciousness.
The result showed that healt h issues influenced cooking culture,
food habits, availability of cooking time, religious and cultural
aspects that ultimately influenced energy consumption to a
certain extent and influenced the IAQ of the kitchen. However,
this study could not provide enough statistical data on th e
relationship.
4. Discussions
Environmentally, kitchen design and culture had been improved
due to electric kitchen hoods for better air quality. In contrast,
the air quality results showed the inner-city kitchen
environment, especially in the rental spaces lacking ventilation,
exhaust fans, and chimneys. It has been identified that time
spent in higher pollutant kitchens has significant risk factors for
acute respiratory infection s. In this regard, Lee et al. (2012) and
Rahman & Islam (2016) investigated that kitchen hood system
can reduce CO2 concentration (@ 1.5 m/s hood system Vs.
close vent) by ten times by the use of an efficient hood system
to maintain thermal comfort quite well inside the kitchen space.
One of the contributing factors to an increased level of CO2 in
the Kathmandu urban kitchen was found as increased
occupancy, cooking culture, and cooking fuel types. Shen et al.
(2020) and Taneja et al. (2008) underlined that cooking
activities contributed to emitting CO2, including other
pollutants.
Additionally, the trend of increased indoor CO2 lev els was
higher in winter compared to summer. In this regard, factors
included indoor activities, closed ventilation, stagnant
pollutants, and human occupancy duration played a role in
increasing CO2 concentration due to limited floor area and
human metabolism. However, information on IAQ in the
1,045
1,630
1,824
1,485
827
663
2,150
0
500
1000
1500
2000
2500
7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 0:00
CO2 concentration (ppm)
Time (hour)
D3 D12 D8 D2 D6 D13
1,681
2,250
3,634
2,683
3,030
1,337
1,497
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
19:00 20:00 21:00 22:00 23:00
CO2 concentration (ppm)
Social event period (hour)
D6 D2 D3 D12 D8 D13
63 SONA 2021|The Architectural Response on Global Challenges
emissions without proper ventilation. They have to cook ethnic
foods on firewood and eye irritation, and some have mild
respiration problems, but it was taken as normal due to a lack of
awareness of IAQ. People living in small units without windows
and poor indoor air quality (IAQ) potentially pose severe
concerns for occupants' health and well-being. In particular,
those conditions might have affected more in the current
pandemic context COVID-19 (Peters & Halleran, 2020).
Women's cooking hours were increased during the COVID-19
pandemic, and kitchen indoor air quality was often overlooked.
4. Conclusions and Recommendations
Indoor air quality is one of the environmental indicators to
demonstrate the sustainability level of the city. Females of
lower-income groups still suffer from unhealthy cooking space
due to unawareness and unaffordability for the electric kitchen
hoods. The study suggests that IAQ should be a concern of city
development authorities and building-by-laws for not allowing
enclosed kitchens and rooms without proper ventilation and
kitchen hoods. More attention should be given to rental
residents in small compact areas (inner-city) because pollution
levels tend to be higher in smaller spaces. Behavioral change in
occupants is essential to reduce exposure, such as burning
incense, mosquito coil, etc.
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5.
