To Study the Effect of Interventions to Reduce the Indoor Air Pollution in Asthmatic Children of Rural India

ABBREVIATIONS USED IN THIS ARTICLE

ALRI = Acute lower respiratory infections; BMF = Biomass fuel; CO = carbon monoxide; ETS = Environmental tobacco smoke; FENO = Fractional exhaled nitric oxide; HEPA = High efficiency particulate air; IAP = Indoor air pollution; ICMR = Indian Council of Medical Research; LPG = Liquefied petroleum gas; PAH = polyaromatic hydrocarbons; VOC = Volatile organic compounds.

INTRODUCTION

Generally, by far the most important direct health risk is pollution caused by the inadequate burning of fuel in low competence of stoves and lamps utilized for cooking and space heating.¹ Household air pollution represents 7.7% of the worldwide death rate, which most of these individuals are under the poverty line and live in low-and middle-income countries.¹ In the last 20 years, epidemiological exploration data have shown the significant effect of air pollution on respiratory health of a common population, especially children and older having underlying chronic lung health problem.² The unfavorable health impacts may be due to short-term (a few minutes to 24 hours) exposure or long‑term (months to decades) exposure to indoor air pollution.^3,4

According to the World Health Organization (WHO) Report 2018,¹ more than 3 billion individuals use biomass fuels (BMFs) and devices, such as coal, dung, and wood in simple stoves for their daily cooking that produces a significant level of household air pollution, which is the world’s single prominent environmental health risk. Burning of fuels, such as coal, wood, and dung in inefficient stoves or open hearths produces a variety of health-damaging pollutants, including particulate matter (PM), carbon monoxide (CO), methane, volatile organic compounds (VOC), and polyaromatic hydrocarbons (PAH). Burning of kerosene oil in simple wick lamps also produces significant emanations of fine particles and other pollutants.¹ Particulate matter is the most common type of air pollutant that causes the most serious impact on human health as it contains a broad range of different types of toxic substances.⁵ The term PM comprises solid particles airborne/or droplets. These particles may range in size (PM₁₀, PM_2.5, and PM₁), composition, and origin.²

Children have excessive ventilation rate, and subsequently, they are more exposed per kg body weight to air pollutants levels than adults. These factors make children more helpless against air pollutants and increase the severity of unfavorable effects.^6,7 Exposure of children to these thin particulate matter <2.5 micrometer diameter (PM_2.5) of outdoor origin is related to decrements in lung function, increments of pediatric emergency visits in the department of asthma,⁸ and more risk of hospitalization.⁹

In Fresno, air purifiers with intervention decrease the indoor PM_2.5 levels with significant enhancement in nasal symptoms in children with allergic rhinitis. They found that the indoor PM_2.5 levels can be decreased in homes by using air purifiers with high efficiency particulate air (HEPA) filters, and these improvements in indoor air quality index can improve the nasal symptoms scores. Reducing indoor PM_2.5 might be an effective method of improving clinical outcomes in patients with allergic sicknesses.¹⁰

The exposure level of PM_2.5 is higher for individuals who use BMF for cooking than for people who use electricity or liquefied petroleum gas (LPG). The usage of BMF for cooking is found to be a significant source of higher levels of exposure in the population of rural areas. Hu R et al.¹¹ in China prescribed to replace the old stoves and biomass with clean fuel stoves, like electric and LPG, and new cooking strategies in order to decrease PM_2.5 exposures and enhance respiratory health in the rural areas.¹¹ There is no study on the reduction of indoor air pollution (IAP) and respiratory health symptoms among the asthmatic children by a change in household fuel use and its long-term impact on respiratory symptoms and treatment morbidity from north India. The present study was done to assess the impact of interventions to decrease IAP on respiratory health symptoms and morbidity in asthmatic children living in rural areas of Delhi-NCR.

The aim of this study was to estimate the effects of BMF combustion on IAP, respiratory symptoms, and treatment-associated morbidities among children suffering from asthma and also to evaluate the association between incremental decreases in pollutant levels and the incidence of respiratory symptoms and treatment morbidities by this intervention/follow-up.

MATERIALS AND METHODS

RESULTS

Fifty-six asthmatic children were enrolled in this interventional follow-up study from 42 households. Out of 56 asthmatic children, 28 were males and 28 were females with a mean age of 9.27 ± 3.94 years. Among the 56 asthmatic children, most of the children (28.6%) were of the first birth order, followed by second (26.8%), third (23.2%), and fourth (21.4%). The majority of the children (85.71%) were vegetarian, while 14.29% were non-vegetarian or had mixed food habits. Only 33.9% of children were going to school by vehicle and the rest 66.1% of children were going to school by foot. Out of the 56 children, 44.6% of children were living in nuclear families and 28.6% and 26.8% were living in joint and the extended family, respectively. Most of the asthmatic children (92.86%) have belonged to the middle class and 7.14% belonged to the lower class (Table 1).

Overall, at least one family member was found as smoker in 31/42 (73.81%) households with pack years ≥30 in 38.1% and <30 pack years in 35.7%. Only one smoker was present in 19 (45.24%) households, followed by two smokers in 7 (16.67%) and three smokers in 5 (11.9%) households. In most of the households (66.67%), smokers smoked in front of children. In 12 (28.57%) households, the smoker smoked anywhere in the house, followed by open place and room (8, 19.05%), room and veranda (3, 7.14%), open place (3, 7.14%), room (3, 7.14%), and veranda (2, 4.76%) separately. Most significantly, only 19, 45.24% of households were aware about the ill effects of smoking. Out of 42 households, smokers (who were not family members) visited the house daily in 5, 11.9%, a few times a week in 6, 14.3%, a few times a month in 12 (28.6%), and occasionally 3 (7.1%) households. No smoker visited the house in 16 (38.1%) households, and other demotic details are given in Table 1.

DISCUSSION

In the present study, the average PM₁₀, PM_2.5, and PM₁ levels observed in the households using BMF at baseline/pre-intervention was observed to be 312.7, 171.6, and 137.6 µg/m³, while it decreased 194.18, 134.94, and 112.9 µg/m³ individually following after the 3 months of change in cooking fuel to secure fuel (LPG). The decreased level of particulate matters further decreased or the decrease sustained up to 9 months of follow-up. These high concentrations of PM levels were due to the pollutants being generated during the burning of the various forms of the BMF, and also because of poor ventilation in the cooking area in the study population. Similar to our finding, Pathak U et al. recently in a study showed that the concentration of PM₁₀ and PM_2.5 was significantly higher in the BMF group compared with LPG group.¹³ The high level of indoor particulate matter with the use of BMFs has been demonstrated in other studies from different parts of India and international studies also.^14–17

The results of this interventional study demonstrated that change in cooking fuel from BMF to LPG is directly associated with the reduced average concentration of different indoor PM levels and also significantly diminish the risk of respiratory morbidity. This change in the level of particulate matters is due to the complete combustion of fuel, diminished degree of smoke, particulate matters, and gases with LPG. This decrease in PM levels may also be explained by awareness among family members about the ill effect of BMF exposure and other environmental smoke like second-hand smoke particularly in children after intervention and advice given by the study team. Our findings are predictable with the outcomes of Hye-Kyung Park et al., Fresno study.¹⁰ They found that the average indoor PM_2.5 concentration was reduced by 43% in the active group when HEPA filter was used as an intervention tool among asthmatic children. Similarly, Rufo et al.¹⁷ in a study of SINPHONIE-based recommendations in a European school found that the guideline-based recommendation significantly reduced the indoor PM_2.5 and PM₁₀ concentrations in the classroom. Oluwole O et al.¹⁸ In another study, it was shown that the indoor PM_2.5 and carbon monoxide (CO) levels were higher in houses cooking with firewood in rural communities of Nigeria. The indoor PM_2.5 and carbon monoxide levels were significantly reduced with the change in cooking style by the introduction of low-emission stoves in their study.

These changes in cooking fuel decline the level of particulate matter which leads to a decrease in respiratory symptoms, morbidity, and medication use among asthmatic children. The above changes are seen within 3 months of intervention in cooking fuel, and the majority of changes either further decrease or remain sustained at 6 and 9 months follow-up. By demonstrating a significant decrease in exacerbations when BMF is substituted with secure fuel or low-emission stoves like LPG in homes, the current study's findings further support the Government of India's effort Ujjwala Yojna to improve the control of asthma symptoms and minimize morbidity in children. Similar to our finding, Park HK et al.¹⁰ in a study found that the allergic disease symptoms in the form of asthma control score and total nasal symptoms score among asthma/allergic rhinitis patients were significantly reduced with indoor particulate matter level after using HEPA filter as intervention tool among asthmatic children. Rufo JC et al.,¹⁷ in their study found that the guideline-based recommendation significantly reduced the indoor PM_2.5 and PM₁₀ concentrations in the classroom; however, no significant differences in atopic prevalence and fractional exhaled nitric oxide (FENO) level were seen. Gurley ES et al.¹⁹ observed that every hour of exposure to PM_2.5 concentrations exceeding 100 μg/m³ was associated with a 7% increase in the frequency of acute lower respiratory infections among children aged 0–11 months in the urban Bangladesh population. They suggested that interventions to diminish dependence on biomass for cooking in this community would reduce exposures to PM_2.5 and could decrease the frequency of ALRI among newborn children. Oluwole O et al.¹⁸ in a study showed that there is a significant reduction in the frequency of respiratory symptoms in mothers and children after a change in cooking fuel to low-emission stoves from firewood in rural communities of Nigeria. However, the moderate airway obstruction on spirometry did not improve after intervention.¹⁶ Again, Oluwole O et al.²⁰ in a study found that BMF was used for cooking in 51.1% of households. Children from the BMF households had a higher proportion of possible asthma and symptoms of severe asthma compared with cleaner fuels. They also found evidence that rural children might be underdiagnosed for asthma. Dherani M et al.²¹ in a meta-analysis concluded that despite the heterogeneity of studies, IAP from solid fuel use has a risk of pneumonia in young children increased by a factor of 1.8. The decrease in household indoor air pollutants from solid fuel use through switching to other fuels, improving combustion, ventilation, and potentially different measures would make a significant contribution to the prevention of pneumonia morbidity and mortality.

The present study demonstrates that the BMF fuel use for cooking leads to increase IAP in the form of increases in the level of various particulate matter. This IAP level can be diminished with the use of secure fuel in the form of LPG. The increase in IAP and poor ventilation conditions in cooking areas leads to increases in the risk of various respiratory symptoms and respiratory morbidity (hospitalization, emergency visit, school loss, and medication use) in asthmatic children. The change in cooking fuel decreases the respiratory symptoms within 3 months of intervention which further decreases or is sustained still 9 months of follow-up. Similarly, Belanger K et al.²² in a review concluded that exposure to indoor burning sources may rises the risk of asthma and its severity in children. Characteristics of the device (recurrence, intensity of use, type and age of appliance) and of the home (i.e., size and ventilation) result in considerable variability in exposures to different indoor air pollutants. We suggest changing the cooking and heating fuel in all rural areas of our country to secure fuel in the form of LPG and other low-emission stoves. There should also be health awareness programs in all rural areas about the ill effects of solid fuel combustion and environmental smoke, such as second-hand smoke and its effect on respiratory health particularly in children.

CONCLUSION

Biomass fuel increases the IAP (particulate matters) that may increase the respiratory symptoms and morbidity among asthmatic children in rural areas. This intervention/follow-up (3, 6, and 9 months) study showed that the change in the cooking fuel from biomass to LPG was found to be the key factor to diminish indoor air pollutants, and hence it decreases respiratory symptoms and morbidity. So, the changes in the cooking fuel are better to reduce the indoor particulate matters (PM₁₀, PM_2.5, and PM₁) that controls asthmatic symptoms and decreased morbidity. Hence, this study concludes that when BMF is replaced with secure fuel/or low-emission stoves like LPG in houses, a significant reduction of exacerbation was found, which shows the Government of India’s Initiative (UJJWALA YOJNA) to better asthma symptoms control and decrease morbidity in children.

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