|Year : 2022 | Volume
| Issue : 4 | Page : 415-420
Realistic personal exposure assessment of air pollutants and health outcomes – A cross-sectional study among Kolkata slum dwellers
Arup Chakraborty1, Arista Lahiri2, Shibaji Gupta3, Nibedita Banerjee4, Asim Saha5, Urmila Dasgupta6
1 Associate Professor, Department of Community Medicine, Medical College, Kolkata, West Bengal, India
2 Associate Professor, Department of Community Medicine, IIT, Kharagpur, West Bengal, India
3 Senior Resident, Department of Community Medicine, Midnapore Medical College, Midnapore, West Bengal, India
4 Counsellor, Department of Transfusion Medicine, Belle Vue Clinic, Kolkata, West Bengal, India
5 Scientist, Department of Public Health, Regional Occupational Health Centre (ICMR), Kolkata, West Bengal, India
6 Professor, Department of Community Medicine, Jagannath Gupta Institute of Medical Sciences, Kolkata, West Bengal, India
|Date of Submission||11-Nov-2022|
|Date of Decision||18-Nov-2022|
|Date of Acceptance||18-Nov-2022|
|Date of Web Publication||31-Dec-2022|
240, Golpukur Road, P. O. Baruipur, 24 Parganas (S) - 700 144, West Bengal
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Rapid, unplanned, and unsustainable patterns of urban development can result in many emerging environmental and health hazards. One of the important public health problems of urban environment is regular exposure to dust and pollutants and consequence of such exposure in the form of changes in the pulmonary function. Being the immediate environment, indoor pollution poses a higher risk to human health than the ambient environment. Realistic personal exposure assessment gives the actual idea about the exposure status. Objectives: This study determined the household principal environmental exposures (Dust, SO2, NO2, and total volatile organic compound) among urban slum dwellers and assessment of the respiratory function to determine any possible relationship between those exposures and outcomes. The study also described the knowledge, attitude, and practice of these urban slum people regarding air pollution and its effect. Methods: A cross-sectional study was carried out among 442 urban slum people residing in the slums of the Kolkata Municipal area. Household environmental exposures were collected by standardized methods and outcome was observed by conducting a pulmonary function test. Finally, knowledge, attitude, and practice regarding air pollution were carried out with the help of a questionnaire-based survey. Results and Discussion: Almost all the pollutants exposure was associated with impairment of lung function. Younger age and female gender were statistically associated protective factors for the development of any lung disease. Those who had an overall good awareness regarding the means and effects of air pollution were found to be protected from developing lung disease. Using exhaust ventilation, relocation to inner side of slums, using personal protective measures, and adequate pollution awareness can help the slum citizens to overcome the problem.
Keywords: Air pollution, exposure, Kolkata, personal, realistic, slum
|How to cite this article:|
Chakraborty A, Lahiri A, Gupta S, Banerjee N, Saha A, Dasgupta U. Realistic personal exposure assessment of air pollutants and health outcomes – A cross-sectional study among Kolkata slum dwellers. Indian J Public Health 2022;66:415-20
|How to cite this URL:|
Chakraborty A, Lahiri A, Gupta S, Banerjee N, Saha A, Dasgupta U. Realistic personal exposure assessment of air pollutants and health outcomes – A cross-sectional study among Kolkata slum dwellers. Indian J Public Health [serial online] 2022 [cited 2023 Feb 1];66:415-20. Available from: https://www.ijph.in/text.asp?2022/66/4/415/366572
| Introduction|| |
Over the last 50 years, the world has witnessed a dramatic growth in urban population. The speed and the scale of this growth, especially in the less developed regions, continue to pose formidable challenges to individual countries as well as to the world community. The global urban population is expected to rise to 61% by 2030. India, the second most populated country in the world, has experienced large-scale development in and around its urban areas. The city of Kolkata has been aggressively multiplying in size over the last three decades. Rapid, unplanned, and unsustainable patterns of urban development can result in many emerging environment and health hazards. As urban populations grow, the quality of the urban environment will play an increasingly important role in public health. One of the important public health aspects in urban population is regular exposure to air pollutants as well as its consequences in the form of changes in the pulmonary function. According to the World Health Organization, air pollution is associated with a broad spectrum of acute and chronic health effects. Recently, high emissions of suspended particulate matter (SPM) have been observed at Kolkata. Being the immediate environment, indoor pollution poses a higher risk to human health than the ambient environment. Indoor pollution can come from sources outside the home as well as from sources within home. Within megacities, slum dwellers have been cited as a particularly vulnerable group. Hence, there is a priority to study urban health issues and its related environmental factors.
Studies from worldwide as well as India looked at the effects of air pollution. However, majority of them looked at the ambient and fixed site exposure assessment. Hence, evidence is lacking on realistic personal exposure assessment at household level., An inaccurate quantification of true exposure may lead to exposure misclassification and considerable uncertainty in health risk estimates. The availability of Global Positioning System and portable sensors presents an enormous opportunity for personal sampling studies by tracking the air pollution exposure and time-activity patterns at the individual level in real-time. This approach can reflect the significant degree of variability over space and time. The challenges, however, are the high cost of implementation and the hardness in collecting repetitive measures on the same group of the population over the term. Worldwide only few studies have conducted to describe the personal real-time exposure so far. Exposure to different air pollutants in the household microenvironment of urban slums of a metropolitan city and their possible relationship with health problems has not been studied in India. There are also very limited number of studies which describe the knowledge, attitude, and practice of the urban slum people regarding air pollution and its effect and possible prevention., Existing climate policies do not address the vulnerability and risks faced by slum dwellers, despite the fact that they comprise a major share of urban population. Hence, this study has looked into the exposure status of different air pollutants at household level and their health outcome among slum dwellers of Kolkata and gave some need-based recommendation.
| Materials and Methods|| |
An observational cross-sectional study was carried out among 442 urban slum people who were permanent residents and more than 12 years of age. The subjects resided throughout the day at home were included in the study. The subjects who were already diagnosed with pulmonary diseases were excluded from the study. Multistage random sampling was carried out among different wards of Kolkata Municipal Corporation. First, four administrative boroughs were chosen from 15. Boroughs were chosen in such a fashion so that representation from various geographical areas was obtained, i.e., from North Kolkata, Central Kolkata, South Kolkata, and from an industrial belt. All the wards were line listed from each borough and one was chosen from each borough randomly. Finally, all the registered slums were line listed from each ward and one was selected by simple random process from each ward.
The environmental exposures (PM2.5, PM10, SO2, NO2, Total Volatile Organic Chemicals) were collected by standardized methods and outcome was observed by conducting pulmonary function test (PFT) with the help of the standard procedure mentioned elsewhere. Finally, knowledge, attitude, and practice regarding air pollution were carried out with the help of a questionnaire-based survey. The exposure of pollutants was stratified into two geographical locations due to the difference in exposure magnitude (whether near to main road or inside the slums based on cutoff of 200 m from the beginning of slum). The study proposal was submitted to the institutional Ethics Committee of Medical College, Kolkata, and approved. The approval letter no was mc/kol/iec/academic/313/04-2014, Dated May 17, 2014. Written informed consent (or assent as in case may be) was obtained from all the participants before participation in the study. Utmost care was taken for maintaining the anonymity of the study subjects.
| Results|| |
Four-hundred and forty-two respondents participated in the research. Among them, 217 (49.1%) were residing toward the main road and the remaining 225 (50.1%) resided away from the road, i.e., in an inner location within the slum.
Sociodemographic profile of the participants
[Table 1] depicts the sociodemographic profile of the respondents classified as per their area of residence. Most of the participants were aged 36–50 years (166, 37.6%), male (247, 55.9%), currently married (308, 69.7%), Hindu by religion (422, 95.5%), having a nuclear family (278, 62.9%), and belonging to lower middle socioeconomic status (133, 30.1%) as per modified BG Prasad scale, 2020.
|Table 1: Sociodemographic profile of the study participants according to location of their residence (n=442)|
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Majority of the respondents resided in a Pucca house (294, 66.5%). However, the presence of a separate kitchen was noted in 218 (49.3%) houses overall. Among those houses having a separate kitchen, majority (164, 75.2%) did not have any open space adjacent to their kitchen. Liquefied petroleum gas (LPG) was the cooking medium used by majority (286, 64.7%), while majority reported that they did not have any exhaust fan in their kitchen (163, 72.4%). In majority (262, 59.3%) of the houses, overcrowding and inadequate ventilation was noted, while none of the houses had cross-ventilation.
One hundred and forty-one (32.0%) subjects admitted to be currently smoker, and 170 (38.5%) reported current smoking history among family members. Out of the current smokers who responded regarding detailed smoking habits, majority (50, 36.0%) were smoking tobacco for the past 10–20 years, while 80 (57.6%) reported to smoke 6–10 cigarettes/bidis per day.
Exposure and outcome
It is observed from the findings that those residing near the main road had a higher level of household exposure of pollutants. Mean (±standard deviation) values of NO2, PM10, PM2.5, SO2, and indoor total volatile organic compound (TVOC) were higher among those residing nearer to the main road than inside the slum houses. The differences observed were statistically significant [Table 2].
|Table 2: Distribution of participants according to level of exposure to different air pollutant compounds and their location of residence (n=442)|
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For PFT parameters the median value was higher among those residing toward the road, with exception of forced expiratory volume (FEV1) [Supplementary Figure 1] and peak expiratory flow rate values. However, the differences observed were not statistically significant.
[Table 3] describes the different types of lung diseases observed among the respondents. Very strikingly, it was observed that overall, 69% of subjects have impaired lung function. Those residing toward road and [Supplementary Figure 2] have a higher proportion of diseased lungs. The observed difference was statistically significant (P = 0.003). Obstructive lung diseases were more common among those residing toward the road, and the trend was statistically significant.
|Table 3: Distribution of participants according to types of lung diseases and location of residence (n=405)|
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Knowledge, attitude, and practice related to air pollution
Majority (346, 78.3%) of subjects have heard about “air pollution.” Automobile emissions and factory emissions were answered as the key source of air pollution by majority of the respondents (70.6% and 64.3%, respectively). Respiratory effects such as breathing difficulty and asthma were the major adverse effects of exposure to air pollution as opined by majority of respondents (79.1% and 52.5%). Overall, 196 (44.4%) of the respondents were aware of the fact that establishing greenbelt could be a potential solution. However, this knowledge was significantly better among those residing in the inner locations. One hundred and forty-one (31.9%) knew that there were rules and regulations in place to curb air pollution. Majority of the respondents had felt that the air quality was presently poor compared to previous years. Among the respondents, 174 (39.4%) had reported to be affected by air pollution. Irritation of the eyes, nose, and throat was the most common experience, followed by breathing difficulty. Some of the respondents reported that they have consulted their neighbors to find a way to protect from air pollution (51, 11.5%) and some even said that they contributed to lessening air pollution actively (112, 25.3%). In both situations, better response was obtained from those who were residing in the interiors of the slum. However, visiting a doctor to treat the effects of air pollution was not a much common practice (43, 9.7%). Only 30 (6.8%) individuals have reported regarding using of protective equipment to prevent exposure.
Association between exposure and development of disease
Apart from PM2.5 and indoor TVOC all other pollutants were significantly associated with lung impairment [Table 4]. As evident from the multiple logistic regression, younger age and female gender provided protection from the development of any lung impairment due to air pollution [Supplementary Table]. Among the environmental pollutants, the level of SO2 had identified to be significantly associated with the risk of developing lung disease. Those who had an overall good awareness regarding the means and effects of air pollution were found to be protected from developing lung disease. The model depicted had a Nagelkerke R2 of 0.210. The Hosmer–Lemeshow's test of model sphericity was statistically not significant (P = 0.754).
|Table 4: Association of different levels of air pollutants with diagnosed lung diseases (n=405)|
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| Discussion|| |
Ambient urban air quality in most megacities has been found to be critical and Kolkata Metropolitan City is no exception this. An analysis of ambient air quality in Kolkata was done in 2017, where the presence of remote patient monitoring (RPM), SPM, NO2, and SO2 and their annual average concentration were classified into four different categories, namely, critical, high, moderate, and low pollution. Out of a total of 17 ambient air quality monitoring stations operating in Kolkata, five fell under the critical category, and the remaining 12 locations fell under the high category of NO2 concentration, while for RPM, four recorded critical, and 13 came under the high pollution category. The causes might be due to vehicular emission (51.4%), followed by industrial sources (24.5%) and dust particles (21.1%). In the same study, a health assessment was undertaken with a structured questionnaire at some nearby dispensaries which fall under areas with different ambient air pollution levels. It showed that respondents with respiratory diseases (85.1%) outnumbered waterborne diseases (14.9%) and include acute respiratory infections (60%), chronic obstructive pulmonary diseases (7.8%), upper respiratory tract infection (URTI) (1.2%), influenza (12.7%), and acid-fast bacillus (3.4%). The pulmonary function status of Kolkata inhabitants was compared during rainy (July–August) and winter (November–January) seasons. During the winter, PFT values were significantly lower compared to rainy season. Regression analysis showed decrement in pulmonary functions as the duration of stay was increased and decrement was more during winter in comparison to rainy season. In both occasions, the PFT values were found higher in high economic class of people. Respiratory impairments were also found higher during winter and males were having worse impairment compared to females. The same gender difference was observed in realistic personal exposure measurement in the present study. Another cross-sectional observational study was carried out among 531 nontobacco addicted adult primary homemaker women residing in slums of Ahmedabad city of Gujarat; which concluded that the reduction of pulmonary function parameters among the study participants was related with kerosene and biomass fuel usage in the kitchen.,, A community-based survey of PFT was conducted in Punjab among rural women who were using biomass fuel and urban women who mostly used LPG. The ventilatory tests showed a highly significant decline in rural women. The cause of decrease in the flow volume in the rural women using biomass fuel was due to respirable SPM such as SO2, NO2, CO2, and CO. The cause of better-preserved lung function in urban women was due to use of other cleaner fuels for cooking, i.e., LPG gas and well-ventilated homes. In the present study, majority household were using LPG as cooking fuel, hence it did not observe such a relationship. A different study carried out in Bihar observed that there was significant decreased pulmonary function in the urban smoker population. In Andhra Pradesh, smoking habits were compared between urban industrial and rural agricultural workers. It showed a significant increase in Vital Capacity (VC) value, significantly lower FEV 1% and reduced forced expiratory flow 25%–75% value being demonstrated in rural than among the urban workers. Smoking was shown to produce airway obstruction in both urban and rural workers. The present study did not observe any such relationship among the smokers and nonsmokers.
The present study also highlighted air pollution-related knowledge, attitude, and practices among the participants. Understanding the knowledge and behavior of the population is key to the development and implementation of necessary intervention programs. Majority of the participants' attitude/beliefs regarding air pollution suggested that they were not much bothered by the air pollution in their locality. Only 6.8% of individuals reported to have used protective equipment such as mask and air purifier mostly by the people who resided in the inner side of the slums. A survey of public awareness, perceptions, and attitudes on air quality in urban India was conducted among 11 major cities including Kolkata, in the year 2017. The survey found the majority of respondents across cities claim to be reasonably aware about air pollution but their actual understanding/knowledge appears to be lower. In a study in Ghana of Africa reported that majority of the respondents were aware of the haze (air pollution) and its adverse effects on health. There was a significant relationship observed between the sociodemographics and air pollution awareness. Although the majority of the respondents were aware of air pollution and its relationship to their health, rates of awareness were low in some demographic groups such as the elderly and the less educated. In Shanghai, a cross-sectional survey was conducted among two groups of people, one group was the caregivers of children and the other was from the nearby communities. The study demonstrated a significant difference of average knowledge scores between the two groups. The parents' educational level and average annual household income were the two strongest factors on knowledge awareness. In addition, a significant difference was noted between the two groups in their attitudes toward air quality and their perception of the government's efforts to alleviate it. Both the groups also showed significant differences in practices geared toward protecting their children's health. In Southern California, lower pulmonary function was associated with ambient exposure to nitrogen dioxide (P = 0.005), acid vapor (P = 0.004), particulate matter (PM2.5) (P = 0.04), and elemental carbon (P = 0.007). Exposure to pollutants was associated with clinically and statistically significant reduction of lung function among the adults. This finding is with the tune with the present study. In Taiwan, higher Ozone exposure was associated with the development of lung disease after adjusting other potential confounders.
Conclusion and Limitations
Apart from PM2.5 and indoor TVOC, all other pollutants were statistically significantly associated with lung impairment. Younger age and female gender were statistically associated protective factors against the development of lung disease due to air pollution. Among the environmental pollutants, the level of SO2 in the residence was identified to be significantly associated with the risk of developing lung disease. Those who had an overall good awareness regarding the means and effects of air pollution were found to be protected from developing lung disease. In the study, seasonal variation of air pollutants was not accounted for and all the greenhouse gases were not considered.
The study recommended at least an exhaust fan to the families to improve their indoor air quality. It was quite evident from the study that the exposure of common air pollutants (NO2, SO2, PM10) are significant contributing factors behind the development of lung disease. The proportion of respiratory diseases is higher among those residing near the roadside than the inner area of the slums. Hence, relocation of the families toward the inner location can be a potential solution. The subjects who are residing toward roadside should use personal protective equipment. It was established from the study that, subjects who had higher level of knowledge in relation to air pollution were significantly better protected from the development of lung disease. Hence, health education emphasizing to the preventive measures may be required for the slum dwellers to get rid of the problem.
We would like to acknowledge UG, PG students of Medical College, Kolkata.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]