Household air pollution (HAP) presents numerous health challenges. The association between HAP and sleep problems has not been extensively studied. This paper examined the effect of HAP due to solid fuel use on sleep problems among older adults in India. Data from the initial phase of the Longitudinal Aging Study in India, which included 51,060 individuals aged 50 years and older, was utilised. Sleep problems were defined as experiencing difficulty falling asleep, waking up during the night, or waking up too early at least five times per week and were classified as a binary variable. Exposure to HAP was defined as the use of solid fuel for household purposes. Multivariate logistic regression was employed to assess the association, and additionally, interaction analysis was conducted to explore the potential moderating effects of age, gender, and residence on this association. The prevalence of sleep problems among older adults was around 12.7%. Sleep problems were higher among older adults who used solid fuel for cooking (OR = 1.25; 95% CI: 1.17, 1.33) and other purposes (OR = 1.13; 95% CI: 1.06, 1.20) in the adjusted model. The place of cooking, ventilation, and type of stove played a significant role in the association between solid fuel use and sleep problems. Individuals over 65, females, and those residing in rural areas were particularly vulnerable to sleep problems due to HAP exposure. The findings highlight the importance of reducing HAP exposure by transitioning to clean fuels as a public health priority within initiatives aimed at promoting healthy aging.

Bangladesh is experiencing a rapid increase in hypertension prevalence, particularly in socio-economically disadvantaged communities. The higher use of solid fuel in these communities could be one of the significant factors contributing to this trend, but evidence supporting this hypothesis is limited in Bangladesh. Therefore, this study aims to investigate the associations of household solid fuel use and its exposure level with systolic and diastolic blood pressure (DBP) and hypertension. We analysed 7,320 women’s data from 2017/18 Bangladesh Demographic and Health Survey. We considered three outcome variables: (i) systolic blood pressure (BP) (continuous response), (ii) DBP (continuous response), and (iii) hypertension status (yes, no). Our primary exposures of interest were fuel type (clean vs solid) and the potential level of household air pollution exposure through solid fuel use (unexposed, moderately exposed, and highly exposed). We used a multilevel mixed-effects Poisson regression model with robust variance to determine association between exposure and outcome variables while adjusting for confounders. Of the total respondents analysed, approximately 82% used solid fuel for cooking. The age-standardised prevalence of hypertension was 28%. Respondents using solid fuel were found to be 1.44 times (95% confidence interval [CI], 1.04–1.89) more likely to develop hypertension compared to clean fuel users. Compared to women using clean fuel, the likelihood of hypertension was found to be 1.61 times (95% CI, 1.07–2.20) higher among the moderately exposed group and 1.80 times (95% CI, 1.27–2.32) higher among the highly exposed group. Similar associations were reported for systolic and DBP. The use of solid fuel increases the risk of becoming hypertensive and elevates systolic and DBP. Policies and programmes are necessary to increase awareness of the adverse effects of solid fuel use on health, including hypertension. Efforts should be made to reduce solid fuel use and ensure proper ventilation systems in households where solid fuel is used.

The performance of the solid fuel ramjet is accurately predicted using full part simulation of this propulsion system, where the flow fields of the intake, combustion chamber, and the nozzle are numerically studied all together. The conjugate heat transfer is considered between the solid phase and the gas phase to directly compute the regression rate of the fuel. The finite volume solver of the compressible turbulent reacting flow is utilized to study the axisymmetric three dimensional flow fields, and two blocks are used to discretize the computational domain. It is shown that the combustion chamber's pressure is changed due to the fuel flow rate's increment which must be taken into account in predictions. The results demonstrate that omitting the pressure dependence of the regression rate and also the effect of the combustor's inlet profile on the regression rate, which specially exists when simulating the combustion chamber individually, under-predicts the solid fuel burning rate when the regression rate augmentation technique is applied to improve the performance of the solid fuel ramjets. It is also illustrated that using the inlet swirl to increase the regression rate of the solid fuel augments considerably the thrust level of the considered SFRJ, while the predictions without considering all parts of the ramjet is not accurate.