Primary Cooking Research Articles

Cultural and Economic Barriers in Switching to Clean Cooking Energy: Does Women’s Agency Make a Difference?

The major objective of this study is to identify and analyze cultural and economic barriers to sustained adoption of LPG (liquefied petroleum gas) as the primary clean cooking energy in India, and examining underpinning values and norms in socio-technical energy system of the country. In 2016, the Government of India introduced a mega scheme called Ujjwala for clean cooking energy with LPG connects in women’s name. This policy, however, experienced limited implementation, but did lead to enhancing women’s agency in many areas. Women’s agency is defined briefly as their ability to set goals, develop capacities, and act on their defined goals to realize desired outcomes in wellbeing and capabilities. In the case of switching to clean cooking energy, the question can be posed as: as women are the ones who carry out most of the onerous work of collecting and cooking with wood, are they able to make decisions on the adoption of clean cooking fuel, that enhance their agency and the wellbeing of their families? Male-centred cultural and economic norms can be changed by the exercise of women’s agency, when (1) women have unmediated asset ownership rights to land, houses, and energy technology; (2) they are organized in groups for earning cash incomes and energy access; (3) they have acquired new knowledge, skills, and finances to acquire and operate new technologies; and (4) women have experienced the effects of policy change addressing gendered norms.

Adverse birth outcomes associated with household air pollution from unclean cooking fuels in low- and middle-income countries: A systematic review

Approximately 3.8 billion people in low- and middle-income countries use unclean fuels as a source of primary cooking fuel as well as for heating. For pregnant women, the toxic chemicals produced by combustion of unclean fuels not only affect women's health directly, but particulate matter and carbon monoxide are absorbed in maternal blood and cross the placental barrier impairing fetal tissue growth. PRISMA 2009 guidelines were used for this systematic review. The inclusion criteria were quantitative, peer reviewed journal articles published within a date range of May 1, 2013–June 12, 2021 examining birth outcomes related to household air pollution from type of cooking fuel in low- and middle-income countries. The quality of available evidence was evaluated using the Office of Health Assessment and Translation (OHAT) risk of bias rating tool. Of the 553 studies screened, 23 satisfied the inclusion criteria. Of the studies that met the inclusion criteria, 14 were cross-sectional, 5 cohort, 1 case-control and 3 randomized control trials conducted across 15 different countries. A range of birth outcomes are reported across studies including birthweight (19), small for gestational age (6), spontaneous abortion (3), preterm birth (6), stillbirth (7) and neonatal mortality (6). The reviewed studies presented evidence for an increased risk of low birth weight (LBW), preterm birth (PTB), small for gestational age (SGA), stillbirth, neonatal mortality and reduction in birthweight with solid fuel and kerosene use compared to cleaner fuels like gas and LPG. Systematically reviewing the evidence and risk of bias ratings illuminated several gaps in the current literature related to exposure assessment, outcome measurement and adequacy of adjustment for confounding.

Pay-as-you-go LPG: A mixed-methods pilot study in urban Rwanda

2.8 billion people still cook with biomass fuels, resulting in devastating impacts on health, gender equity and the environment. Pay-as-you-go (PAYG) liquid petroleum gas (LPG) is a new technology designed to make LPG affordable for urban biomass users by allowing customers to pay for fuel in small amounts. This mixed-methods study (N = 64) combined stove usage data, cooking diaries, household interviews and telephone surveys to examine a commercial PAYG LPG pilot in Kigali. It aimed to understand how households used PAYG LPG and its potential in accelerating access to clean cooking in urban Rwanda.PAYG LPG rapidly displaced charcoal as the primary cooking fuel for the majority of participants, resulting in a mean monthly reduction in household fuel expenditure of 3240 RWF (3.50 USD) and a mean consumption of 1.2 kg/capita/month. Participants spanning all income brackets in Kigali made use of PAYG LPG. The ability to pay in smaller amounts seemed to be critical to initial adoption and sustained use during the pilot. Follow-up activities with a small subsample of participants (N = 10) found that 70% continued to use full cylinder LPG (typically 12 kg) as their primary cooking fuel in the two months after the PAYG service was withdrawn. Throughout the pilot almost all participants continued to use charcoal, which accounted for 21% of cooking events. We identified a range of drivers of fuel stacking that encompassed both cultural and practical factors such as cylinder delivery delays and taste preferences for certain foods.We conclude that PAYG LPG could contribute to the clean cooking transition in urban Rwanda, but that larger scale pilots are needed to better understand both the supply- and demand-side viability.

Electric Cooking Diary in Bangladesh: Energy Requirement, Cost of Cooking Fuel, Prospects, and Challenges

Detrimental effects exerted by biomass-based traditional cookstoves on health, environment, hygiene, and the soaring price of gas makes it imperative to investigate the feasibility of electric cooking as a promising clean cooking fuel in the context of Bangladesh. However, the adoption of electric cooking is unlikely to be welcomed if the monthly cost of electricity consumed by the electric cooking appliances is not comparable to traditional cooking fuels. So far, no study has been reported in this respect. Therefore, this paper is aimed to assess the energy consumption of available electric cooking appliances for cooking typical Bangladeshi dishes. Estimated monthly electricity cost of electric cooking is also reported and then compared to that of traditional cooking fuels. For the study purpose, three respondent families were provided with a rice cooker, hot plate, induction cooker and electric pressure cooker for cooking their daily meals. After four months of use, data related to dish cooked, amount of food, cooking time, and energy consumption were collected which shows that hot plate and rice cooker were the least preferred appliances due to their poor workmanship and limited use respectively. On the contrary, despite the fact that electric pressure cookers cannot perform all types of frying, it was the most preferred appliance owing to its ability to significantly reduce the cooking time and its less energy consumption. Induction cooker was less preferred for the additional requirement of compatible cook pots. The study also reveals that monthly energy requirements for electric cooking varied from 72–87 kWh corresponding to a cooking electricity bill ranging from BDT 504–609 per month (USD 6–7.5) which is less expensive as compared with biomass and LPG based cooking. This paper also highlights the prospects and challenges associated with the adoption of electricity as the primary cooking fuel in Bangladesh.

Formation and evolution of secondary organic aerosols derived from urban-lifestyle sources: vehicle exhaust and cooking emissions

Abstract. Vehicle exhaust and cooking emissions are closely related to the daily life of city dwellers. Here, we defined the secondary organic aerosols (SOAs) derived from vehicle exhaust and cooking emissions as “urban-lifestyle SOAs” and simulated their formation using a Gothenburg potential aerosol mass reactor (Go:PAM). The vehicle exhaust and cooking emissions were separately simulated, and their samples were defined as “vehicle group” and “cooking group”, respectively. After samples had been aged under 0.3–5.5 d of equivalent photochemical age, these two urban-lifestyle SOAs showed markedly distinct features in the SOA mass growth potential, oxidation pathways, and mass spectra. The SOA/POA (primary organic aerosol) mass ratios of vehicle groups (107) were 44 times larger than those of cooking groups (2.38) at about 2 d of equivalent photochemical age, according to the measurement of scanning mobility particle sizer (SMPS). A high-resolution time-of-flight aerosol mass spectrometer was used to perform a deeper analysis. It revealed that organics from the vehicle may undergo the alcohol and/or peroxide and carboxylic acid oxidation pathway to produce abundant less and more oxidized oxygenated OAs (LO-OOAs and MO-OOAs), and only a few primary hydrocarbon-like organic aerosols (HOAs) remain unaged. In contrast, organics from cooking may undergo the alcohol and/or peroxide oxidation pathway to produce moderate LO-OOAs, and comparable primary cooking organic aerosols (COAs) remain unaged. Our findings provide an insight into atmospheric contributions and chemical evolutions for urban-lifestyle SOAs, which could greatly influence the air quality and health risk assessments in urban areas.

Development of wood-burning rocket cookstove with forced air-injection

Nearly 40% of the world's population still relies on biomass stoves as their primary cooking source. Indoor cooking with biomass stoves produces harmful emissions such as fine particulate matter (PM2.5) and can result in significant cardiovascular and respiratory disease. Air injection technology, in the forms of over-fire, under-fire, and staged (a combination of under- and over-fire), has been used for decades to reduce emissions in small-scale industrial biomass burners. Recently, researchers have begun integrating air-injection into biomass cookstoves, but the number of studies is limited, and improper air-injection can result in worsening stove performance. In this paper, we develop and analyze three wood-burning biomass rocket stove air-injection strategies using computational fluid dynamics and experiments. We consider over-fire and under-fire air-injection independently, and then develop a staged air-injection system that combines the optimal jet characteristics from the purely over-fire and under-fire systems. Results show that significant performance gains, both in terms of reduced emissions and increased burn-rate are achievable with forced air-injection. For a radial over-fire air injection system, jet momentum flux is found to control fuel and air mixing and is the driving metric for reducing particulate emissions. For the under-fire system, excess air ratio was found to control both the emissions rate and firepower. In a comparison of all three air-injection strategies, over-fire air injection was found to have the largest reduction in emissions, under-fire air injection had the largest increase in firepower and reduction in boiling times, and the staged air injection method achieved both improved emissions and burn-rate. Additionally, the combustion start-up phase was observed to account for the majority of emissions in all forced-draft stoves, and is most sensitive to under-fire injection, remaining an area ripe for improvement.

Household transitions to clean energy from traditional biomass in Nepal: Challenges and opportunities

In recent years, the Nepal government has recognized and prioritized several clean energy initiatives in its national plans and policies. Despite this, more than two-thirds of households still rely on traditional biomass, as their primary source of energy, for cooking and heating, making the household fuelwood consumption per person in Nepal among the highest in the world. However, why households’ transitions to clean energy for cooking is slow has been poorly understood. Using energy-specific information from the World Bank’s Multi-Tier Framework (MTF) survey and the Nepal government’s Multiple Indicator Cluster Survey (MICS), the cooking and heating energy consumption situation of households across the provinces by rural and urban areas is analyzed briefly. Also, a simple levelized cost of cooking is estimated using different fuel-technology combinations. The main findings of this paper are: limited availability, unreliable supply and high costs are hindering households’ transitions to clean energy from traditional biomass; the combination of fuelwood, liquified petroleum gas and other clean energy sources (multiple fuel stacking) are common within the same household; and, the use of biogas, and to some extent, solar power, for cooking is limited to scale and geographical location. It is expected that electricity will be the most economic and common primary clean cooking energy option for households in the future provided that the government has the policy to address the reliability concerns of electricity and that it is affordable for low-income households.

Impact of LPG promotion program in Ghana: The role of distance to refill

This study investigates the impact of a clean cooking intervention on primary fuel choice and on households’ willingness to pay for an improved LPG distribution model in Ghana. Using data obtained via a survey of 904 households in two beneficiary districts, we found that the intervention led to higher LPG usage. The program increases the probability of households choosing LPG as a primary cooking fuel by 24% and the rate of use of LPG among households by 33%. Furthermore, an analysis of willingness to pay shows that delivery preference is not statistically different between beneficiary and control groups. The distance to refill the cylinder significantly affects LPG usage and willingness to pay. A policy that brings LPG refill closer to households and reduces the time and money cost of accessing a refill station is key to increasing the adoption of LPG as the primary cooking fuel.

Household Air Pollution From Solid Cooking Fuel Combustion and Female Breast Cancer.

Background: Women bear a large share of disease burden caused by household air pollution due to their great involvement in domestic activities. Pollutant emissions are believed to vary by exposure patterns such as cooking and space heating. Little is known about the independent effect of solid cooking fuel combustion on breast cancer risk. We aimed to examine the association of indoor coal and wood combustion for cooking with breast cancer risk.Methods: During June 2004–July 2008, participants aged 30–79 from 10 diverse regions across China were enrolled in the China Kadoorie Biobank. Primary cooking fuel use information in up to three residences was self-reported at baseline. Multivariable logistic regression models yielded adjusted odds ratios (ORs) and 95% confidence intervals (CIs).Results: A total of 290,396 female participants aged 30–79 were included in the main analysis. Compared with long-term clean fuel users, the fully adjusted ORs were 2.07 (95%CI: 1.37–3.13) for long-term coal users, 1.12 (95% CI: 0.72–1.76) for long-term wood users, and 0.98 (95% CI: 0.55–1.74) for those who used mixed solid fuels to cook. Those who had switched from solid to clean fuels did not have an excess risk of breast cancer (OR: 0.88, 95%CI 0.71–1.10).Conclusion: Long-term solid fuel combustion for cooking may increase the risk of breast cancer. The strength of association is stronger among coal users than wood users. Targeted interventions are needed to accelerate the access to clean and affordable energy.

Barriers to and facilitators of uptake and sustained use of LPG through the PMUY in tribal communities of Pune district

The Pradhan Mantri Ujjwala Yojana (PMUY), launched in India in 2016, is the world's largest program to provide cleaner cooking fuel to poor households. The PMUY may yield large health benefits because of increased LPG use, and more importantly, reduced chulha use, and thus may significantly reduce household air pollution exposures. This research, conducted in a tribal, difficult-to-reach area of Pune District, leveraged PMUY to study the uptake, adoption, usage, and health benefits of LPG. This work highlighted barriers to and facilitators of adoption and sustained LPG usage. Our findings have program implications and need to be addressed to ensure that poor households continue to use LPG as their primary cooking fuel.Our study indicates that most households expressed a desire to own an LPG gas stove but are not aware about the methods to avail the scheme and rely on the local governments to obtain the LPG. The perceived benefits of using LPG differ among people, depending on their own experiences. The most common perceived benefits include ease of use and less time spent on cooking. However, most people are unaware of the severe health effects of HAP, which, if known, might influence their decision to own and use LPG for cooking. The challenges in availing the scheme include varying registration amount, lesser awareness of the document requirements and multiple trips to the distributors' office to fulfil the documentary requirements. Further, the sustained use is hampered by the non-subsidized refills and unavailability of transport facilities for the refill replacement. Further, the beneficiaries are unaware that the subsidy goes towards the repayment of the loan and more clarity is expected from the distributor when availing the scheme.In conclusion, the population in tribal regions is willing to use the LPG regularly if the refill costs are subsidized. Further increasing logistical and financial support to rural distributors will help in better uptake.

Cooking with biomass fuels increased the risk for cognitive impairment and cognitive decline among the oldest-old Chinese adults (2011–2018): A prospective cohort study

BackgroundsWhile the pernicious effects of outdoor air pollution on cognitive ability have been previously examined, evidence regarding household air pollution is scarce. MethodsUsing data from the Chinese Longitudinal Healthy Longevity Survey, we explored the relationship between cooking with biomass fuel and cognitive impairment and cognitive decline using a Cox proportional hazards model. We further assessed the correlation of biomass fuels and cognitive score using a generalized estimating equation. Cognitive ability was measured based on the Chinese version of the Mini-Mental State Examination (MMSE) and cognitive impairment was defined as MMSE < 24 points and cognitive decline was defined as a reduction of MMSE ≥ 3 points. On follow-up, we investigated the effect of switch-cooking combustibles on cognitive ability. ResultsThe mean (SD) age of 4161 participants was 81.7 (10.0) years old. The reported cooking with biomass fuels was correlated with an elevated risk of cognitive impairment (hazard ratio (HR): 1.19, 95% confidence interval (CI): 1.04, 1.37) and cognitive decline (HR: 1.18, 95% CI: 1.04, 1.33). Besides, cooking with biomass fuels was related to a decrease in cognitive score (β: −0.43, 95% CI: −0.73, −0.14). In comparison to persistent biomass fuel users, participants who reported changing their primary cooking fuels from biomass to clean fuels exhibited a reduced risk of cognitive impairment (HR: 0.68, 95% CI: 0.57, 0.82) and cognitive decline (HR: 0.66, 95% CI: 0.56, 0.76) and a higher cognitive score (β: 0.72, 95% CI: 0.17, 1.26). Cooking without ventilated cookstoves was associated with a higher risk of cognitive impairment (HR: 1.31, 95% CI: 1.10, 1.58) and cognitive decline (HR: 1.18, 95% CI: 1.02, 1.38), regardless of types of cooking fuels. Interaction and stratified analyses showed relatively poor cognitive ability in participants who engaged in irregular exercise or were not living with family members. ConclusionsCooking with biomass fuels was correlated with a higher risk of cognitive impairment and cognitive decline. Among the oldest-old population, this risk may, however, be lower for those changing their primary cooking fuels from biomass to clean fuels.

Microfinance for clean cooking: What lessons can be learned for scaling up LPG adoption in Kenya through managed loans?

Liquidity constraints are a key barrier to acquisition and sustained use of clean household energy in resource-poor settings. This study evaluates a pilot microfinance initiative in Kenya to help low-income rural households access liquefied petroleum gas (LPG) for cooking. Program beneficiaries received a six-month loan that covered all equipment costs and was to be repaid in monthly installments. We present results from surveys of beneficiaries (n = 69) after they began using LPG, as well as 332 non-beneficiaries from the same community (to understand how beneficiaries and non-beneficiaries differ in cooking patterns and socioeconomic outcomes). 94% of beneficiaries had repaid their loan in full and on time at the time of data collection. Meanwhile, beneficiaries were more likely than non-beneficiaries to use LPG as their primary cooking fuel (76.8% of beneficiaries versus 38.8% of non-beneficiaries). While 81.1% of beneficiaries who used LPG as their primary cooking fuel reported multiple fuel use, we find beneficiaries increased LPG use by 5.9 h per week with a corresponding decrease of 4.8 h in weekly use of biomass fuel. Our findings suggest that promoting LPG usage through microloans for equipment is likely to be both commercially viable and beneficial to health through decreased use of polluting biomass fuel.

Estimating disease burden attributable to household air pollution: new methods within the Global Burden of Disease Study

BackgroundDespite a substantial reduction in the use of solid fuels worldwide, exposure to household air pollution (HAP) from use of these fuels for cooking remains a leading risk factor for global disease burden. Among environmental risk factors, the contribution of HAP to disease burden is second only to ambient particulate matter pollution. We present updates to our modeling methodology as well as our latest findings on attributable burden estimates. MethodsWe estimated HAP-attributable burden for cataract, chronic obstructive pulmonary disease, ischaemic heart disease, lower respiratory infections, lung cancer, neonatal disorders, stroke, and type 2 diabetes for 204 countries and territories from 1990 to 2019. We used spatio-temporal Gaussian Process Regression to model data from observational surveys and censuses reporting primary cooking fuel to estimate the proportion of individuals using a specific solid-fuel type (wood, coal/charcoal, agricultural residues, or dung) by location. We converted the fuel exposure estimates to year, location, and sex/age-specific PM2·5 exposures with a regression mapping function using household air pollution measurements. Using a Bayesian meta-regression tool, we estimated relative risk as a function of PM2·5 exposure for each disease based upon a systematic review of the epidemiological literature on indoor and ambient air pollution. We then combined our exposure estimates and relative risks to estimate population attributable fractions and attributable burden for each cause. FindingsIn 2019, 91·5 million global disability-adjusted life years (DALYs) (95% uncertainty interval 67·0–119) were attributable to HAP, a decline of more than 50% from 1990. We estimated 2·31 million (1·63–3·12) global deaths were attributable to HAP and accounted for over 4% of all deaths in 2019. HAP-attributable burden remains highest in sub-Saharan Africa and south Asia, with 3770·3 (2876·4–4720·2) and 2068·0 (1412·5–2799·7) age-standardised DALYs per 100 000 population, respectively. InterpretationAlthough the disease burden attributable to HAP decreased considerably between 1990 and 2019, it remains a significant risk factor. Our internally consistent methodology and comprehensive approach to estimation of HAP-attributable burden provides a robust resource for global health interventions. Efforts to transition to cleaner household energy sources should be accelerated. FundingBill & Melinda Gates Foundation.

Associations between the household environment and stunted child growth in rural India: a cross-sectional analysis.

Stunting is a major unresolved and growing health issue for India. There is a need for a broader interdisciplinary cross-sectoral approach in which disciplines such as the environment and health have to work together to co-develop integrated socio-culturally tailored interventions. However, there remains scant evidence for the development and application of such integrated, multifactorial child health interventions across India's most rural communities. In this paper we explore and demonstrate the linkages between environmental factors and stunting thereby highlighting the scope for interdisciplinary research. We examine the associations between household environmental characteristics and stunting in children under 5 years of age across rural Rajasthan, India. We used Demographic and Health Survey (DHS)-3 India (2005-2006) data from 1194 children living across 109,041 interviewed households. Multiple logistic regression analyses independently examined the association between (i) the primary source of drinking water, (ii) primary type of sanitation facilities, (iii) primary cooking fuel type, and (iv) agricultural land ownership and stunting adjusting for child age. The results suggest, after adjusting for child age, household access to (i) improved drinking water source was associated with 23% decreased odds [odds ratio (OR) = 0.77, 95% confidence interval (CI) 0.5-1.00], (ii) improved sanitation facility was associated with 41% decreased odds (OR = 0.51, 95% CI 0.3-0.82), and (iii) agricultural land ownership was associated with 30% decreased odds of childhood stunting (OR 0.70, 95% CI 0.51-0.94]. The cooking fuel source was not associated with stunting. Our findings indicate that a shift is needed from nutrition-specific to contextually appropriate interdisciplinary solutions, which incorporate environmental improvements. This will not only improve living conditions in deprived communities but also help to tackle the challenge of childhood malnutrition across India's most vulnerable communities.

ARE URBAN RWANDAN HOUSEHOLDS USING MODERN ENERGY SOURCES? AN EXPLORATION OF COOKING FUEL CHOICES

This study employed a discrete choice framework to explore cooking energy use patterns amongst urban Rwandan households using the latest EICV 5 microeconomic survey dataset. Specific analysis focused on choices for three primary cooking fuels namely: firewood, charcoal and liquidified petroleum gas. The findings show that ordered model provided better prediction for primary fuel choices rather than the secondary choices for multiple fuel users with income as a key determinant. Furthermore, asset index, house ownership, geographical location, number of rooms, household size and household head labor market participation were some of the non-price factors that significantly affected the choice probability for using charcoal as transitional fuel and liquidified petroleum gas as a modern fuel in Rwandan country context. Robustness test of the results emphasizes the need for government in collaboration with modern energy suppliers to have clean energy use campaigns and do market segmentation through repackaging of smaller gas cylinders so that many low- and middle-income households become aware and use modern energy services. This is essential to ensure good prospect of energy transition for the developing country case context amidst urbanization and climate change.Keywords: Energy; Households; Urban; Rwanda; FuelJEL Classifications: D12, O12, Q420DOI: https://doi.org/10.32479/ijeep.10735

Paraffin dangers, health and socioeconomic consequences: Urgent need for policy action

Illuminating paraffin (kerosene) is the primary cooking fuel for approximately two million South Africans. The highly flammable and toxic fuel is burnt in poorly made stoves that are prone to malfunction and are associated with accidental fires, burns and household air pollution. However, the fuel continues to be used as it is easily decanted, widely available in neighbourhood outlets, perceived as affordable, and often the only available option for low-income urban settlements. It is anticipated that increased and enforced home congestion during COVID-19 lockdowns will exacerbate exposure of homebound families to unsafe energy, especially during the cold winter months. Based on an accumulation of evidence on the health and socioeconomic impacts of paraffin, this article advocates for its expedited phase-out and substitution with safer energy.

Household Energy Use Among Female-Headed Households in Urban Ethiopia: Key Issues for the Uplift of Women

This article examines the linkages between cooking energy and gender based on a study conducted in Arba Minch town of southwestern Ethiopia. It primarily investigates cooking energy end-use within female-headed households (FHHs) residing in the town and specifically focuses on women who disproportionately suffer the impacts of energy accessibility. This study reveals that commercial cooking fuels are increasingly scarce and expensive, and the costs of modern cooking appliances are beyond the purchasing ability of most urban FHHs. Meeting the energy requirements in sustainable manner, thus, continues to be a major challenge that hinders FHHs’ efforts to improve their living situations. The results further show that though the income is an important factor, it is not the only powerful determinant in the consumption of cooking fuels within FHHs. Other socioeconomic characteristics were found to have a significant impact too. This study further examines the relevance of the “fuel stacking” model and finds that the majority of the FHHs, regardless of their economic status, depend on wood fuels as their primary cooking energy source. Even when family incomes rose, complete transition to cleaner fuels has not taken place; instead, it added fuels in the fuel stacking process.

Moving up the energy ladder: does socio-religious status matter?

This paper investigates the role played by socio-religious categories in determining primary cooking fuel choices among Indian households. We study this role in the broader context of climbing up the energy ladder. Our estimates based on a sample of 601,509 households and using multinomial probit regression suggest that socio-religious status along with economic status is critical in the choice of modern eco-friendly fuels. We find that belonging to a marginalized community in Hindu religion significantly dampens a households’ likelihood to move up the ladder when compared with upper caste households. While intra-religion differences among Hindu castes in terms of their probability of using modern fuels are wider, differences among Muslims appear smaller. Also, though Muslims perform worse than Hindu upper castes in terms of probability of using modern fuels they are much better off in comparison with other Hindu castes. Our results remain robust to alternative specifications and several robustness checks.

Solid fuel-related indoor air pollution and poor sleep quality in the elderly: a national longitudinal study in China

Background: Sleep disorders are a public health issue in an aging society. Outdoor air pollution has been linked to poor sleep quality, but few studies have investigated the relationship between indoor air pollution from solid fuel combustion and sleep quality in elderly. Objective: To evaluate the association between indoor air pollution due to cooking solid fuels and sleep quality among elderly in China. Methods: We analyzed data from CHARLS, a national survey of ~17,000 residents aged over 45 from 150 counties in China. Participants were restricted to those who completed waves of CHARLS in 2011, 2013, and 2015 (n=8,668). Sleep quality was indicated by self-reported average sleep duration (hours/night) and the numbers of restless days per week in the 2015 survey. Participants also reported household cooking fuel type in all three surveys. We compared the “solid fuels”, primarily coal and wood burning, with the “clean fuels” including electric, natural gas, and liquefied petroleum gas as the reference. Years of solid fuel use (0, 1-4 or ≥5 years) were evaluated. We used multinomial logistic regression to estimate the odd ratios (OR) and 95% confidence interval (CI) for sleep duration (7-9 hours/night as the reference) and restless sleep (0 day as the reference) according to fuel types adjusting for potential confounding factors.Results: Solid fuels use for 5 or more years was associated with a shorter duration of sleep (OR=1.17 95%CI 1.02, 1.35 for ≤6 hours/day) and higher frequencies of restless days of sleep (OR=1.30 95%CI 1.11, 1.52 for ≥5 days/week) compared with clean fuels users. The associations were smaller in magnitude for solid fuels use in 1-4 years. Conclusions: Primary cooking fuel was associated with poor sleep quality in an elderly Chinese population. Further research of the specific type of fuels and indoor air pollutants to inform intervention strategies.

Particle exposures and health effects in peri-urban South India: findings from the CHAI Project

We provide an overview of findings from the Cardiovascular health effects of air pollution in Telangana, India (CHAI) project, a recent effort to investigate health effects of household and ambient particle exposure in a cross-sectional cohort study. We developed a local land use regression model to estimate particle exposure for all households within 28 villages outside the city of Hyderabad using data from a measurement campaign. Mean measured PM2.5 was 34 (sd 3.2) µg/m3 and black carbon (BC) was 2.7 (sd 0.5) µg/m3. Approximately 60% of households reported using biomass as the primary cooking fuel. To integrate across multiple relevant sources of particle exposure in the population, we developed a model of average personal exposure based on personal exposure measurements (n=610, 24 h avg) and participants’ self-reported usual activities and behaviours. Personal exposure to PM2.5 and BC was predicted for all participants in the cohort (n=6000). Personal exposure measurements were not correlated (Rspearman &lt; 0.2) with annual ambient concentration at residence modeled by land-use regression. Predictors of personal exposure in women included cooking activities and household socioeconomic position, while in men predictors were smoking and occupation. We provide an overview of results from epidemiological analyses to estimate the independent effects of ambient particles and primary cooking fuel on carotid intima media thickness, blood pressure, and blood glucose levels. We also present results regarding the association between predicted personal exposure and vascular function measures over a wide exposure range (e.g. mean PM2.5 51 µg/m3 (IQR=9.4) for men, 61 µg/m3 (IQR=12.9) for women). We discuss lessons learned regarding investigating ambient air pollution in settings with high exposure to household air pollution and challenges using more personalized exposures in epidemiological analysis and how findings from CHAI fit within the broader context of air pollution health effects studies in Indian populations.