|Year : 2022 | Volume
| Issue : 1 | Page : 63-69
A study on the perceived impact of indoor air pollution in a slum area of Kolkata, West Bengal
Sinjita Dutta, Vineeta Shukla, Mausumi Basu, Meghna Mukherjee, Ankita Mishra, Ripan Saha
Department of Community Medicine, Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal, India
|Date of Submission||21-Jun-2021|
|Date of Decision||16-Nov-2021|
|Date of Acceptance||01-Dec-2021|
|Date of Web Publication||24-Jan-2022|
Dr. Vineeta Shukla
Department of Community Medicine, Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal
Source of Support: None, Conflict of Interest: None
BACKGROUND: Indoor air pollution is one of the most serious environmental health concerns in today's times.
OBJECTIVES: The objective is to find out the sources and health effects of indoor air pollution as well as assess the housing conditions among residents of a slum area in Kolkata.
MATERIALS AND METHODS: A community-based cross-sectional study was conducted among 220 households in a slum area of Kolkata. Data were collected using a predesigned, pretested, structured schedule by face-to-face interview and observation technique and analyzed using SPSS version 25.0.
RESULTS: About 56.8% of the study population complained of having at least one symptom of indoor air pollution. Factors associated with three or more symptoms were female gender, lower-middle socioeconomic class, absence of dampness, exposure to tobacco smoke, use of mosquito repellent, and presence of kitchen in the living room.
CONCLUSION: The slum population should be educated about the major associated factors of indoor air pollution found in our study.
Keywords: Housing, indoor air pollution, mosquito repellent, slum, tobacco smoke, urban
|How to cite this article:|
Dutta S, Shukla V, Basu M, Mukherjee M, Mishra A, Saha R. A study on the perceived impact of indoor air pollution in a slum area of Kolkata, West Bengal. Indian J Health Sci Biomed Res 2022;15:63-9
|How to cite this URL:|
Dutta S, Shukla V, Basu M, Mukherjee M, Mishra A, Saha R. A study on the perceived impact of indoor air pollution in a slum area of Kolkata, West Bengal. Indian J Health Sci Biomed Res [serial online] 2022 [cited 2022 May 22];15:63-9. Available from: https://www.ijournalhs.org/text.asp?2022/15/1/63/336296
| Introduction|| |
Indoor air quality refers to the quality of air which is present in and around residential or official buildings. When indoor air quality is degraded to a certain level by harmful contaminants, it is known as indoor air pollution.
Indoor air pollutants include, physical dust and suspended particulate matter (PM), chemical disinfectants, floor cleaners, pesticides, insect repellents, gases such as carbon monoxide and nitric oxides, and biological bacteria, fungi, microbial spores, and animal dander. Major sources of indoor air pollution are fuel combustion practices, smoke emitted from tobacco products, building material, and furnishings such as asbestos, flooring with tiles and carpets and furniture and cabinets made of certain processed wood products, household cleaning and disinfectant products, heating and cooling devices, spraying of insecticides and pesticides, heavy metals such as lead and polluted outdoor air which contains gases such as radon, oxides of sulfur, carbon monoxide, and hydrofluorocarbons.
Indoor air pollution can be 10 times worse than outdoor air pollution. Women and young children are particularly vulnerable as compared to men as they spend most of their time at home. Common morbidities associated with indoor air pollution are respiratory diseases such as acute respiratory tract infection, chronic obstructive pulmonary disease, and bronchial asthma, poor perinatal outcomes such as low birth weight and stillbirth, cancer of nasopharynx, larynx, lung, and even leukemias. The indoor air pollutants are usually irritants and cause symptoms such as headache, redness, and itching of eyes, dry cough, runny nose, and dyspnea. A PAN India survey conducted in 2014 showed a significant association between solid fuel use and respiratory diseases in India. A study from Pune, India, revealed positive association between the use of kerosene as cooking fuel and tuberculosis.
According to the WHO, about 4.3 million people in the world die every year from exposure to indoor air pollution. According to The Global Burden of Diseases 2015, the fourth leading cause of disability-adjusted life years in India is attributed to indoor air pollution.
Although relatively clean sources of energy predominate in the developed countries, the situation is not so in developing countries. Here, we find rampant use of fossil fuel with the predominance of overcrowding and lack of ventilation, especially in unplanned settlements such as the urban slums. The slum dwellers are thus more vulnerable due to their unhygienic living conditions and bear the largest exposure burden to indoor air pollution. According to the Center for Science and Environment, indoor air quality in some areas of Kolkata is three times higher than the permissible limit.
This issue is often not addressed as actively as outdoor air pollution. Thus, this study was undertaken in a slum area of Kolkata to provide insight into indoor air pollution and its effect on health.
| Materials and Methods|| |
Study type, design, and area
An observational study, cross-sectional in design, was conducted in a slum area of Kolkata for a period of 6 months (January to June 2020).
Study population, inclusion, and exclusion criteria
The study population was the residents of the selected slums. Inclusion criteria were individuals aged 18 years and above, residing in the slums for1 year or more. Individuals who refused to give consent to participate in the study were excluded.
Taking proportion (p) of perceived indoor air pollution from a study conducted in another slum area in Kolkata as 0.65, q = 1-P = 0.35, Type I error α = 0.05, confidence interval 95% with Z1−α = Z0.95 = 1.96 and absolute precision L = 10%, sample size was calculated using Cochran's formula:
n = Zα2pq/(L) 2
= ([1.96]2 × 0.65 × 0.35)/([0.1]2)
After multiplying by design effect of 2 for multistage sampling, adding 20% nonresponse, and rounding off, the final sample size was calculated to be 220.
The sampling technique opted was multistage random sampling [Figure 1].
|Figure 1: Multistage random sampling technique showing the process of selection of study population (n = 220)|
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The study tools were:
- Predesigned, pretested structured schedule
- Nonstretchable measuring tape.
The schedule was designed by a team of experts including a professor of community medicine, and then pretested among 20 randomly selected households. The reliability was confirmed by Cronbach's alpha (0.78).
Symptoms of indoor air pollution.
- Housing and environmental conditions
- Sociodemographic characteristics: Age, gender, religion, level of education, occupation, and socioeconomic status.
Study technique and data collection
Door-to-door visit of the selected households was done. At first, the head of the family was approached. If unavailable, then any other member giving consent was interviewed. If a resident of any household did not give consent, then the next selected household was approached. If any household was found locked on two consecutive days, then the next household was approached. Data collection was done using face-to-face interview method, observing the housing and environmental conditions and measuring the living area, door, and window spaces.
Data were analyzed using the Statistical Package for the Social Sciences (SPSS for Windows, version 25.0, SPSS Inc., Chicago, Illinois, USA). Bivariate analysis was performed to ascertain the relationship between the dependent and the independent variables. All independent variables having P < 0.20 were considered biologically plausible to be included in the multiple multinomial logistic regression model where a P < 0.05 was considered statistically significant.
Type of house
- Kutcha house–Houses made of mud, thatch, clay, or other low-quality materials
- Pucca house–Houses made up of brick and cement
- Semipucca–Mixed type, for example, the floor is cemented with thatched roofs.
Open space all around the house for proper lighting and ventilation. In urban areas, it may be up to one-third of the total area.
Windows or vents placed on the opposite side of the buildings give natural breeze a pathway through the structure.
Minimum requirement of door and window area
Adequacy of door and window–two-fifth of floor area.
Exposure to tobacco smoke
A person is considered exposed to tobacco smoke if he/she is a smoker or exposed to passive smoking for any duration.
Institutional Ethics Committee permission was obtained before the start of the study (Letter no IPGME and R/IEC/2021/110 dated February 6, 2021). Informed written consent was obtained before each interview, and all ethical principles were strictly adhered to throughout the course of the study.
| Results|| |
[Table 1] shows sociodemographic profile of the study population. About 50.9% of the study population belonged to 21–40 years age group. A little over half (53%) of the study population were females and 45% were homemakers. Nearly one-third of the study population (32.7%) was illiterate. Almost 60% of the population was found to belong to lower and lower-middle class as per Modified BG Prasad scale 2020.
Almost all of the study population (97.7%) were residing in semipucca houses with only one room per family (87.7%). About two-third of the study population had only 100–150 sq. ft for living purposes (65.9%). The combined door and window area were found to be <20% of the total floor space area in about 96.4% of the households. No household was found to have adequate cross-ventilation. Overcrowding was present in 88.2% of the study population. About 35.9% of the study population had their kitchen in the verandah. Due to area constraints, no house was found to have adequate setback area [Table 2].
|Table 2: Distribution of the study population according to housing conditions (n=220)|
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[Table 3] characterizes the sources of indoor air pollution. Dust problem was present in nearly 69% of households. About one-fifth (21.8%) of the study population were exposed to tobacco smoke inside their house. Over 91% of the study population were using mosquito repellent inside their house. Over half of the study population (52.3%) did not have any smoke outlet in their kitchen. Maximum (82.3%) family members used liquefied petroleum gas (LPG) as cooking fuel.
|Table 3: Distribution of the study population according to sources of indoor air pollution (n=220)|
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About 56.8% of the study population complained of having one or more symptoms. Eye irritation and respiratory problems were the most common perceived symptoms (30%) followed by complaint of headache in another 23% of the population [Figure 2].
|Figure 2: Horizontal bar diagram showing the distribution of study population according to perceived symptoms (n = 125)*|
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[Table 4] shows predictors of indoor air pollution. Factors associated with three or more symptoms were female gender (adjusted odds ratio [AOR] for males 0.23), lower-middle socioeconomic class (AOR 3.39), absence of dampness (AOR for the presence of dampness 0.10), exposure to tobacco smoke (AOR 4.52), use of mosquito repellent (AOR 5.19), and presence of kitchen in the living room (AOR 8.59).
|Table 4: Factors associated with symptoms of indoor air pollution: Multiple multinomial logistic regression (n=220)|
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| Discussion|| |
About 97.7% of houses were semipucca type with only one living room on an average (87.7%). This was greater than the findings by Hossain et al. in a comparative study on urban environmental health between Khulna and Rajshahi cities of Bangladesh where 26.6% and 77.1% semipucca type houses were found in Khulna and Rajshahi, respectively. Single living room was found in 56.5% of houses in Khulna and 47.2% of houses in Rajshahi. Overcrowding was present in over 88% of the households in our study. This was more than the findings of Choi et al. in a slum area of Bengaluru and Maharana et al. in Kolkata where overcrowding was found in 61% of the households., Muindi et al. also discussed about the problem of overcrowding in their study in Kenya.
Dampness though a potential source of bioaerosols and microorganisms were found to be a protective factor against indoor air pollution which is a contrast finding to most studies. This may be because dampness was found only in a little over half of the households (59%).
About 82.3% of the study population in our study used LPG as cooking fuel which is slightly more than a pan India study by Faizan and Thakur and DLHS-4 Kolkata data which reports 74.6% and 78.4% urban population use clean fuel, respectively,, whereas according to a study in Pune by Elf et al. 87% of the population used LPG. The use of kerosene as primary fuel was found in only 13.2% of our households which corroborated with the findings in Pune (11%) whereas it was as high as 70% in another study in Nairobi, Kenya and 60% in the study by Maharana et al. This may be due to the fact that kerosene is a cheap and easily available fuel and is still preferred by slum dwellers due to their low socioeconomic status. Switching to clean fuel is not an affordable option for many poor families in India. Furthermore, the scheme Pradhan Mantri Ujjwala Yojana, which aims to distribute LPG connections to below poverty line families, is yet to cover this slum area.
Separate kitchen was found in only 25% of the households whereas some form of smoke outlet (either exhaust fan or thin space between walls and roof) was observed in about 47.7% of the houses. This was one of the important contributing factors to the symptoms perceived by the respondents. However, it was not statistically significant. This contrasted with the findings by Elf et al. which reported a lack of separate kitchens in 45% of the houses.
Exposure to tobacco smoke was present only in 21.8% of the respondents in our study which corroborated with the findings of Kolkata (25%) but was far more than results obtained in Kenya (6.7%)., Problem of smoke exposure inside the living room either due to family member smoking or fumes coming from nearby houses (neighboring effect) was found among 76% of the houses in Pune. Out of 220 households, 40.5% used insect repellents which were less than the findings by Sarkar et al. (90%) and Maharana et al. (62.5%).,
In another study in Pune, it was found that wood as cooking fuel, incense sticks, and mosquito coils were found to be associated with high PM size and were significant contributors to indoor air pollution. This corroborated with our study where the use of mosquito repellents was found to have higher odds of symptoms of indoor air pollution.
Nearly 57% of the slum residents experienced some form of symptoms due to the indoor environment of their homes. In the study from Kolkata slum, nearly 90% of the population were symptomatic with conditions such as eye irritation, difficulty in breathing, dry cough, and chronic respiratory diseases which corroborated with findings by Nandasena S as well.
Our study found females having higher odds of more symptoms as opposed to findings in other studies. This may be due to the fact that females spend most of their time indoors.
Our study population reported that symptoms were aggravated mostly during the winter season (97%). A study undertaken among Delhi slums by Kulshreshtha et al. showed the maximum concentration of indoor air pollutants in households was found during winters and was associated with aggravated respiratory problems. In another national population-based study by Mondal D and Paul P on effects of indoor air pollution among under-five children, use of biomass fuels, absence of a separate kitchen, and smoking behavior of household members were associated with greater risk of acute respiratory infections. These findings also corroborated with our study where exposure to tobacco smoke inside the house and the presence of kitchen in the living room were associated with increased number of symptoms.
A possibility of detection bias might be present as the effect of outdoor air pollution could not be masked. The impact of indoor air pollution was assessed based on perceived symptoms instead of the ideal PM 2.5 concentration. Furthermore, we did not evaluate the pulmonary functions using a spirometer and could not assess how multiple exposures were influencing synergistically.
| Conclusion and Recommendations|| |
More than half of the study population complained of having at least one symptom of indoor air pollution. Educating the slum population about the sources and hazards of indoor air pollution will be the most effective method of controlling the situation. Using mosquito nets instead of mosquito repellent coils and liquids should be encouraged. Furthermore, smoking inside the house must be discouraged. The use of LPG as cooking fuel needs to be encouraged through proper counseling. The problem of lack of a separate kitchen can be addressed by avoiding cooking inside the house when children, pregnant women, or the elderly are inside. If possible, a separate space should be used as kitchen. Research needs to be conducted for proper low-cost housing conditions, especially in slums as indoor air pollution has immense negative impact on health.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]