Reduce Household Air Pollution Research Articles

Impact of randomly assigned “pay-as-you-go” liquefied petroleum gas prices on energy use for cooking: Experimental pilot evidence from rural Rwanda

The disease burden related to air pollution from traditional solid-fuel cooking practices in low- and middle-income countries impacts millions of people globally. Although the use of liquefied petroleum gas (LPG) fuel for cooking can meaningfully reduce household air pollution concentrations, major barriers, including affordability and accessibility, have limited widespread adoption. Using a randomized controlled trial, our objective was to evaluate the association between the cost and use of LPG among 23 rural Rwandan households. We provided a 2-burner LPG stove with accessories and incorporated a “pay-as-you-go” (PAYG) LPG service model that included fuel delivery. PAYG services remove the large up-front cost of cylinder refills by integrating “smart meter” technology that allows participants to pay in incremental amounts, as needed. We assigned three randomized discounted prices for LPG to each household at ∼4-week intervals over a 12-week period. We modeled the relationship between randomized PAYG LPG price and use (standardized to monthly periods), analyzing effect modification by relative household wealth. A 1000 Rwandan Franc (about 1 USD at the time of the study) increase in LPG price/kg was associated with a 4.1 kg/month decrease in use (95 % confidence interval [CI]: −6.7, −1.6; n = 69 observations). Wealth modified this association; we observed a 9.7 kg/month reduction (95 % CI: −14.8, −4.5) among wealthier households and a 2.5 kg/month reduction (95 % CI: −5.3, 0.3) among lower-wealth households (p-interaction = 0.01). The difference in price sensitivity was driven by higher LPG use among wealthier households at more heavily discounted prices; from an 80 % to 10 % discount, wealthy households used 17.5 to 5.3 kg/month and less wealthy households used 6.2 to 3.1 kg/month. Our pilot-level experimental evidence of PAYG LPG in a rural low-resource setting suggests that further exploration of subsidized pricing varied by household wealth is needed to ensure future policy initiatives can achieve targets without exacerbating inequities.

Comprehensive Review on Thermal Performance Enhancement of Domestic Gas Stoves.

Cooking is a daily activity in every household, which consumes energy and produces pollution. Using clean gas fuels instead of traditional solid fuels will significantly reduce household air pollution. Although the use of clean-burning burners can reduce emissions, early domestic gas cookers had poor thermal performance. Currently, even small improvements in efficiency can result in significant energy savings due to the large number of domestic gas stoves in use. There has been a long history of research into the development of domestic gas stoves to improve performance and reduce energy consumption. Meanwhile, research into the use of hydrogen-enriched natural gas as a promising environmentally friendly fuel is increasing. In this paper, we perform a descriptive statistics and graphical visualization of network analysis by combining common databases with Bibliometrix. We also analyze the energy balance of domestic gas stoves and the influence of a single factor and multiple factors on stove performance. Then we provide a detailed overview of some research technologies in enhancing the thermal performance of gas stoves. We also discuss the research progress and application prospects for the use of hydrogen-enriched natural gas as a fuel in domestic gas stoves and identify areas for future research and issues that need attention.

Deepened socioeconomic inequality in clean cooking fuel use in India from 2005-2006 to 2015–2016

Uptake of clean cooking fuels (CCF), such as liquefied petroleum gas (LPG), in place of traditional cooking fuels such as wood, charcoal, and kerosene can improve public health by reducing household air pollution exposures. Though studies have cross-sectionally examined socioeconomic determinants of cooking fuel adoption, little is known about socioeconomic disparities in CCF use over time. Data from the third (2005–06) and fourth (2015–16) rounds of the National Family Health Survey covering 109,041 and 601,509 households, respectively, were used to examine inequities in CCF use in India. While CCF use in India increased nationally from 25% in 2005–06 to 44% in 2015–16, the adoption of CCF varied widely across states and socio-economic groups. Approximately 2% of households in the poorest wealth quintile gained access to LPG during the study period, compared with an increase of 10% or more among households in the middle or richer wealth quintiles; the LPG access gap between the low (0.2%) and middle class (19.2%) was 19% in 2005–06 and nearly doubled to 35% (2.5% vs. 37.4%, respectively) in 2015–16. At the state level, there was a four-fold difference in the uptake of CCF over the two survey periods. The use of CCF increased by less than 10% in Himachal Pradesh, Bihar, Assam, Manipur, Mizoram, and Meghalaya as compared to the increases of at least 30% in Tamil Nadu (42%), undivided Andhra Pradesh (34%), and Kerala (30%). Further, in wealthier states (Delhi, Goa, Punjab, Haryana, Tamil Nadu, Kerala, and undivided Andhra Pradesh), CCF use increased by more than 20% among the poorest individuals compared with less than 1% among the poorest families in lower income states (Tripura, Meghalaya, Madhya Pradesh, Jharkhand, Chhattisgarh, Bihar). To promote a more equitable clean energy transition, poorer and rural Indian households should be prioritized for CCF promotion programs.

Kitchen Characteristics and Practices Associated with Increased PM2.5 Concentration Levels in Zimbabwean Rural Households.

Household air pollution (HAP) from biomass fuels significantly contributes to cardio-respiratory morbidity and premature mortality globally. Particulate matter (PM), one of the pollutants generated, remains the most accurate indicator of household air pollution. Determining indoor air concentration levels and factors influencing these levels at the household level is of prime importance, as it objectively guides efforts to reduce household air pollution. This paper describes household factors associated with increased PM2.5 levels in Zimbabwean rural household kitchens. Our HAP and lung health in women study enrolled 790 women in rural and urban households in Zimbabwe between March 2018 and December 2019. Here, we report data from 148 rural households using solid fuel as the primary source of fuel for cooking and heating and where indoor air samples were collected. Data on kitchen characteristics and practices were collected cross-sectionally using an indoor walk-through survey and a modified interviewer-administered questionnaire. An Air metrics miniVol Sampler was utilized to collect PM2.5 samples from the 148 kitchens over a 24 h period. To identify the kitchen features and practices that would likely influence PM2.5 concentration levels, we applied a multiple linear regression model. The measured PM2.5 ranged from 1.35 μg/m3 to 1940 μg/m3 (IQR: 52.1-472). The PM2.5 concentration levels in traditional kitchens significantly varied from the townhouse type kitchens, with the median for each kitchen being 291.7 μg/m3 (IQR: 97.2-472.2) and 1.35 μg/m3 (IQR: 1.3-97.2), respectively. The use of wood mixed with other forms of biomass was found to have a statistically significant association (p < 0.001) with increased levels of PM2.5 concentration. In addition, cooking indoors was strongly associated with higher PM2.5 concentrations (p = 0.012). Presence of smoke deposits on walls and roofs of the kitchens was significantly associated with increased PM2.5 concentration levels (p = 0.044). The study found that kitchen type, energy type, cooking place, and smoke deposits were significant predictors of increased PM2.5 concentrations in the rural households. Concentrations of PM2.5 were high as compared to WHO recommended exposure limits for PM2.5. Our findings highlight the importance of addressing kitchen characteristics and practices associated with elevated PM2.5 concentrations in settings where resources are limited and switching to cleaner fuels may not be an immediate feasible option.

Assessing Government Design Practices from a Human-Centered Perspective: Case Study of an Improved Cookstoves Program in Colombia

Governments and non-governmental organizations worldwide are promoting the transition to improvedcookstoves (ics), which aim to reduce household air pollution and decrease the use of biomass. This article follows a case-study approach to characterize and assess the design practices applied in a Colombian government-led program to foster the transition to ics in rural households between 2010-2018 in the department of Nariño. Data was collected from direct observation, 23 semi-structured interviews (with program beneficiaries, civil servants, and external stakeholders) and documentary evidence. We assessed the degree to which the program’s formulation, implementation, and evaluation considered the beneficiaries’ specific needs, values, contexts and human experience. We found that the government program design followed a top-down approach focused on a single design principle, efficiency. Moreover, the government’s design methods did not appear to sufficiently involve its potential beneficiaries or consider their actual human experiences and realities. We argue that if the government had applied a more human-centered design approach, it could have enhanced the integration of the socio-cultural backgrounds of the program’s beneficiaries. Overall, the results of this study underscore the importance of integrating human-centered design approaches to identify new paths to improve governments’ responsiveness and effectiveness.

Breathing Room: Cleaner Fuels for Home Cooking in LMICs.

Breathing Room: Cleaner Fuels for Home Cooking in LMICs.

Acceptance and uptake of improved biomass cookstoves in Peru – Learning from system level approaches to transform large-scale cooking interventions

Improved biomass cookstoves (ICS) are cooking technologies that increase wellbeing and reduce household air pollution. With the goal of identifying factors influencing ICS acceptance and uptake at five system levels (intrapersonal, interpersonal, community, institutional, and policy), we carried out a qualitative study in three regions in Peru. We conducted 32 focus group discussions (243 ICS users) and 26 semi-structured interviews with key stakeholders, applying a combination of two system-level frameworks for analysis: the socio-ecological model and the ICS adoption domain.Enabling and impeding factors at each level were closely related to each other. Decisions made by policy makers – often centralised and not considering local/regional realities – strongly influenced acceptance and barriers at lower levels. ICS acceptance and uptake tended to be low when ICS users were not involved from the start. Most ICS programmes focused on stove distribution outputs, without considering community needs, such as training on ICS building, maintenance and repair, or issues related to spare part availability, which is a strong barrier to sustained uptake of ICS.Using a combination of models that allows one to examine facilitators and barriers at multiple levels, as well as the interactions of those levels, was useful in assessing potential improvements to intervention design, facilitating programme success, preventing unforeseen programme adaptations, and improving cost-effectiveness of interventions.

Releasing the killer from the kitchen? Ventilation and air pollution from biomass cooking

Household air pollution from biomass cooking is the most significant environmental health risk in the Global South. Interventions to address this risk mostly promote less-polluting stoves and clean fuels, but their diffusion has proven difficult. This paper assesses the potentially complementary role of ventilation in reducing household air pollution. Using state-of-the-art measurements of kitchen concentrations of particulate matter (PM2.5) and personal exposure from around 250 households in rural Senegal, we show that higher ventilation is strongly related to lower kitchen concentration, though absolute pollution levels remain high. This association is robust to controlling for a comprehensive set of potential confounders. Yet, these reductions in concentration do not clearly translate into lower pollution exposure among cooks, probably due to avoidance behaviour. Our findings indicate that ventilation interventions may reduce smoke concentration nearly as much as many real-world clean stove interventions and can hence be an important complement to existing strategies. However, a more holistic approach is needed in order to reduce personal exposure in line with international health standards.

Associations of Household Solid Fuel Use With Falls and Fall-Related Injuries in Middle-Aged and Older Population in China: A Cohort Study.

Objective: This study evaluated the associations of solid fuels with incidence of falls and fall-related injuries. Methods: Data were taken from wave 1∼4 of the China Health and Retirement Longitudinal Study, including 15,651 participants aged 45years and older. Modified Poisson regression was used to examine the associations of solid fuels with falls and fall-related injuries. Results: Modified Poisson regression analysis showed that solid fuels users for cooking had an increasing incidence of falls and fall-related injuries, with RR of 1.211 (95% CI: 1.124, 1.305) and 1.248 (95% CI: 1.107, 1.408); for heating had an incidence, with RR of 1.178 (95% CI: 1.062, 1.306) and 1.134 (95% CI: 0.963, 1.335); combined for cooking and heating, with RR of 1.247 (95% CI: 1.105, 1.408) and 1.185 (95% CI: 0.982, 1.431). Conclusion: Our study suggests that solid fuel use is associated with a higher incidence of falls and fall-related injuries among adults aged 45 years and older in China. It is necessary to restrict solid fuel use to reduce household air pollution and make stronger environmental protection policies to improve household environment.

Multiple overlapping risk factors for childhood wheeze among children in Benin

BackgroundThe African continent is currently facing an epidemiological transition characterized by a shift from communicable to non-communicable diseases. Prominent amongst the latter are allergies and asthma. In that context, wheeze has multiple potential contributory factors that could include some of the endemic helminth infections, as well as environmental exposures, such as household air pollution. We sought to determine the relative importance of these risk factors among children in Benin.MethodsWe included 964 children aged 6–14 years living in the commune of Comé, south–west Benin. All children were participants in the longitudinal monitoring cohort of the DeWorm3 trial designed to evaluate multiple rounds of community mass treatment with albendazole for interruption of the transmission of soil transmitted helminths (STH). We administered a standard ISAAC questionnaire to determine the presence of wheeze. In addition, we assessed exposure to household air pollution and to other potential allergy-inducing factors, dietary intake and anthropometry. Using STH infection status assessed at the pretreatment baseline timepoint, we used multivariate statistical modelling, controlling for covariates, to investigate associations between wheeze and the different factors measured.ResultsThe prevalence of wheezing history was 5.2%, of current wheezing was 4.6% and of severe wheezing was 3.1%, while STH infections were found in 5.6% of children. These profiles did not vary as a function of either age or gender. Infection with Ascaris lumbricoides, but not hookworm species, was significantly associated with both current wheeze (adjusted Odds Ratio (aOR) = 4.3; 95% CI [1.5–12.0]) and severe wheeze (aOR = 9.2; 95% CI [3.1–27.8]). Significant positive associations with current wheeze, independent of each other and of STH infection status, were also found for (i) use of open cookstoves (aOR = 3.9; 95% CI [1.3–11.5]), (ii) use of palm cakes for fire lighting (aOR = 3.4; 95% CI [1.1–9.9]), (iii) contact with domestic animals and/or rodents (aOR = 2.5; 95% CI [1.1–6.0]), (iv) being overweight (aOR = 9.7; 95% CI [1.7–55.9]). Use of open cookstoves and being overweight were also independent risk factors for severe wheeze (aOR = 3.9; 95% CI [1.1–13.7]) and aOR = 10.3; 95% CI [1.8–60.0], respectively).ConclusionsChildren infected with A. lumbricoides appear to be at elevated risk of wheeze. Deworming may be an important intervention to reduce these symptoms. Improving cooking methods to reduce household air pollution, modifying dietary habits to avoid overweight, and keeping animals out of the house are all additional measures that could also contribute to reducing childrens’ risk of wheeze. Policymakers in LMIC should consider tailoring public health measures to reflect the importance of these different risk factors.

Hydrogen for Cooking: A Review of Cooking Technologies, Renewable Hydrogen Systems and Techno-Economics

About 3 billion people use conventional carbon-based fuels such as wood, charcoal, and animal dung for their daily cooking needs. Cooking with biomass causes deforestation and habitat loss, emissions of greenhouse gases, and smoke pollution that affects people’s health and well-being. Hydrogen can play a role in enabling clean and safe cooking by reducing household air pollution and reducing greenhouse gas emissions. This first-of-a-kind review study on cooking with hydrogen assessed existing cooking technologies and hydrogen systems in developing country contexts. Our critical assessment also included the modelling and experimental studies on hydrogen. Renewable hydrogen systems and their adoptability in developing countries were analysed. Finally, we presented a scenario for hydrogen production pathways in developing countries. Our findings indicated that hydrogen is attractive and can be safely used as a cooking fuel. However, radical and disruptive models are necessary to transform the traditional cooking landscape. There is a need to develop global south-based hydrogen models that emphasize adoptability and capture the challenges in developing countries. In addition, the techno-economic assumptions of the models vary significantly, leading to a wide-ranging levelized cost of electricity. This finding underscored the necessity to use comprehensive techno-economic assumptions that can accurately predict hydrogen costs.

A Descriptive Assessment of Household Air Pollution in Rural Kitchens in Kenya

Efforts to ensure households transition to modern fuels are expected to reduce household air pollution. However, exposure to toxic particles and gases in fuel stacking households remains under-researched. We implemented a household survey to identify household energy sources and assess exposure to particulate matter with diameter of ≤5 microns (PM2.5), ≤10 microns (PM10) and select polluting gases (Sulfur Dioxide (SO2), Total Volatile Organic Compounds (TVOCs), Carbon Dioxide (CO2), Nitrogen Dioxide (NO2), Carbon Monoxide (CO)) in a rural community. Wood was the main cooking fuel in 94.2% (1615/1703) households with fuel stacking reported in 86.1% (1462/1703) of total households. Daily time-weighted average concentrations of PM2.5 and PM10 were beyond World Health Organization (WHO) limits in wood-using households (189.53 (Standard deviation (SD) = 268.80) µg/m3 and 592.38 (SD = 623) µg/m3, respectively) and Liquid Petroleum Gas (LPG) -using households (57.2 (SD = 53.6) µg/m3 and 189.86 (SD = 168) µg/m3, respectively). Only daily average CO and TVOC concentration in wood-using households exceeded recommended levels. Household socio-economic status, education level of the head of household, use of a separate kitchen and household size influenced household energy choices. Rural households using wood as the main cooking fuel are exposed to high levels of particulate matter, carbon monoxide and total volatile organic compounds. LPG-using households may not realize health benefits if stacking with polluting fuels is practiced.

Cleaning the Flue in Wood-Burning Stoves Is a Key Factor in Reducing Household Air Pollution.

In experimental settings, replacing old wood stoves with new wood stoves results in reduced personal exposure to household air pollution. We tested this assumption by measuring PM2.5 and levoglucosan concentrations inside homes and correlated them with wood stove age. Methods: Thirty homes in the Albuquerque, NM area were monitored over a seven-day period using in-home particulate monitors placed in a common living area during the winter months. Real-time aerosol monitoring was performed, and filter samples were analyzed gravimetrically to calculate PM2.5 concentrations and chemically to determine concentrations of levoglucosan. A linear regression model with backward stepwise elimination was performed to determine the factors that would predict household air pollution measures. Results: In this sample, 73.3% of the households used wood as their primary source of heating, and 60% burned daily or almost daily. The mean burn time over the test week was 50 ± 38 h, and only one household burned wood 24/day (168 h). The average PM2.5 concentration (standard deviation) for the 30 homes during the seven-day period was 34.6 µg/m3 (41.3 µg/m3), and median (min, max) values were 15.5 µg/m3 (7.3 µg/m3, 193 µg/m3). Average PM2.5 concentrations in 30 homes ranged from 0–15 μg/m3 to >100 μg/m3. Maximum PM2.5 concentrations ranged from 100–200 μg/m3 to >3000 μg/m3. The levoglucosan levels showed a linear correlation with the total PM2.5 collected by the filters (R2 = 0.92). However, neither mean nor peak PM2.5 nor levoglucosan levels were correlated with the age (10.85 ± 8.54 years) of the wood stove (R2 ≤ 0.07, p > 0.23). The final adjusted linear regression model showed that average PM2.5 was associated with reports of cleaning the flue with a beta estimate of 35.56 (3.47–67.65) and R2 = 0.16 (p = 0.04). Discussion: Cleaning the flue and not the wood stove age was associated with household air pollution indices. Education on wood stove maintenance and safe burning practices may be more important in reducing household air pollution than the purchase of new stoves.

Effects of a Liquefied Petroleum Gas Stove and Continuous Fuel Distribution Intervention on Anthropometric Outcomes at Birth

Background and Aims: Air pollution may contribute to childhood stunting and impaired cognitive development. Potential anthropometric markers of poor growth and cognition include head circumference and length at birth. The Household Air Pollution Intervention Network (HAPIN) trial in India, Guatemala, Peru, and Rwanda was a randomized controlled field trial among 3200 pregnant women that assessed the effect of liquefied petroleum gas (LPG) stove and continuous free fuel intervention compared to cooking with biomass on health outcomes. We conducted an intention-to-treat analysis of the LPG intervention delivered during pregnancy starting at 9-19 weeks of gestation on head circumference and length at birth among offspring. Methods: Length and head circumference were measured in centimeters within 24 hours of birth. Birth length and head circumference z-scores were calculated using INTERGROWTH-21st standards which accounts for gestational age at birth. Separate linear regression models (adjusted for 10 strata, representing settings in Guatemala (1 site), Rwanda (1 site), India (2 sites) and Peru (six sites)) were created for head circumference, head circumference z-score, birth length and birth length z-score. Results: A total of 3060 live births were included in the analysis. The intervention had small or no effect on birth length (β=0.14, 95% CI -0.01 to 0.29), birth length Z-scores (β=0.09, 95% CI 0.01 to 0.16), head circumference (β= -0.01, 95% CI -0.11 to 0.09) and head-circumference Z-scores (β= -0.01, 95% CI -0.08 to 0.07). More than 90% of the women had a full-term pregnancy (94.6% in control and 94.1% in intervention group), and the mean (SD) time with the intervention was 21.23 weeks (3.67 weeks). Conclusion: Our intervention strategy aimed at reducing household air pollution during pregnancy had small or no effects on length and head circumference at birth among offspring. Keywords: Household air pollution, liquefied petroleum gas, biomass fuel, head circumference, birth length, newborn

Reducing household air pollution exposure to improve early child growth and development; a randomized control trial protocol for the “Poriborton-Extension: The CHANge trial”

BackgroundGlobally, household air pollution (HAP) is a leading environmental cause of morbidity and mortality. Our trial aims to assess the impact of liquefied petroleum gas (LPG) for cooking to reduce household air pollution exposure on child health outcomes, compared to usual cooking practices in Bangladesh. The primary aim is to evaluate if reduced exposure to HAP through the provision of LPG for cooking from early gestation through to age 2 improves child anthropometry, health, and neuro-cognitive developmental outcomes, compared to children exposed to emissions from usual practice.MethodsTwo-arm parallel cluster randomized controlled trial (cCRT). We will extend the intervention and follow-up of our existing “Poriborton” trial. In a subset of the original surviving participants, we will supply LPG cylinders and LPG stoves (intervention) compared to usual cooking practices and extend the follow-up to 24 months of age. The expected final sample size, for both (intervention and control) is 1854 children with follow-up to 2 years of age available for analysis.DiscussionThis trial will answer important research gaps related to HAP and child health and neuro-cognitive developmental outcomes. This evidence will help to understand the impact of a HAP intervention on child health to inform policies for the adoption of clean fuel in Bangladesh and other similar settings.Trial registrationThe Poriborton: Change trial: Household Air Pollution and Perinatal and early Neonatal mortality is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12618001214224, original trial registered on 19th July 2018, extension approved on 23rd June 2021. www.anzctr.org.au.

Protocol for a cluster randomised controlled trial of LPG cookstoves compared to usual cooking practices to reduce perinatal mortality and morbidity in rural Bangladesh called Poriborton: the CHANge trial

BackgroundHousehold air pollution is a leading health risk for global morbidity and mortality and a major health risk in South Asia. However, there are no prospective investigations of the impact of household air pollution on perinatal morbidity and mortality. Our trial aims to assess the impact of liquefied petroleum gas (LPG) for cooking to reduce household air pollution exposure on perinatal morbidity and mortality compared to usual cooking practices in Bangladesh.HypothesisIn a community-based cluster randomised controlled trial of pregnant women cooking with LPG throughout pregnancy, perinatal mortality will be reduced by 35% compared with usual cooking practices in a rural community in Bangladesh.MethodsA two-arm community-based cluster randomised controlled trial will be conducted in the Sherpur district, Bangladesh. In the intervention arm, pregnant women receive an LPG cookstove and LPG in cylinders supplied throughout pregnancy until birth. In the control or usual practice arm, pregnant women continue their usual cooking practices, predominately traditional stoves with biomass fuel. Eligible women are pregnant women with a gestational age of 40–120 days, aged between 15 and 49 years, and permanent residents of the study area. The primary outcome is the difference in perinatal mortality between the LPG arm and the usual cooking arm. Secondary outcomes include (i) preterm birth and low birth weight, (ii) personal level exposure to household air pollution, (iii) satisfaction and acceptability of the LPG stove and stove use, and (iv) cost-effectiveness and cost-utility in reducing perinatal morbidity and mortality. We follow up all women and infants to 45 days after the birth. Personal exposure to household air pollution is assessed at three-time points in a sub-sample of the study population using the MicroPEM™. The total required sample size is 4944 pregnant women.DiscussionThis trial will produce evidence of the effectiveness of reduced exposure to household air pollution through LPG cooking to reduce perinatal morbidity and mortality compared to usual cooking practices. This evidence will inform policies for the adoption of clean fuel in Bangladesh and other similar settings.Trial registrationAustralian New Zealand Clinical Trials Registry ACTRN12618001214224. Prospectively registered on 19 July 2019

Assessing the Effects of Cooking Fuels on Anopheles Mosquito Behavior: An Experimental Study in Rural Rwanda.

ABSTRACT.Globally, cleaner cooking fuels are increasingly promoted to reduce household air pollution. However, there is concern that reductions in smoke from biomass fuels could lead to more favorable conditions for mosquitoes and potentially increase vectorborne disease risk. We investigated household entry, host-seeking, household exit, and mortality among Anopheles mosquitoes across three cooking fuel types: wood, charcoal, and liquid petroleum gas (LPG) in six experimental huts in Rwanda. Fifty laboratory-reared Anopheles gambiae mosquitoes were released each night in entry compartments outside each hut, and fuels were burned for 1 hour in the hut verandas. Collectors conducted human landing catch during cooking and for 2 hours afterward, and CDC light traps were used for the rest of the night to measure host-seeking. Differences in each outcome were assessed using generalized linear mixed models with random effects for hut, collector, and day. Cooking with LPG compared with wood and charcoal was associated with substantial increases in household entry and host-seeking. Household exit was not significantly different across fuels, and mortality was lower in LPG-burning huts compared with wood. Although these results are not directly generalizable to field conditions, they indicate a potential for clean fuel adoption to increase exposure to Anopheles mosquitoes compared with traditional biomass fuels. Additional entomological and epidemiological studies are needed to investigate changes in disease vector exposure associated with clean fuel adoption, and evaluate whether enhanced vector control interventions should be promoted in tandem with cleaner cooking fuels.

Biodigester Cookstove Interventions and Child Diarrhea in Semirural Nepal: A Causal Analysis of Daily Observations.

Background:Hundreds of thousands of biodigesters have been constructed in Nepal. These household-level systems use human and animal waste to produce clean-burning biogas used for cooking, which can reduce household air pollution from woodburning cookstoves and prevent respiratory illnesses. The biodigesters, typically operated by female caregivers, require the handling of animal waste, which may increase domestic fecal contamination, exposure to diarrheal pathogens, and the risk of enteric infections, especially among young children.Objective:We estimated the effect of daily reported biogas cookstove use on incident diarrhea among children old in the Kavrepalanchok District of Nepal. Secondarily, we assessed effect measure modification and statistical interaction of individual- and household-level covariates (child sex, child age, birth order, exclusive breastfeeding, proof of vaccination, roof type, sanitation, drinking water treatment, food insecurity) as well as recent 14-d acute lower respiratory infection (ALRI) and season.Methods:We analyzed 300,133 person-days for 539 children in an observational prospective cohort study to estimate the average effect of biogas stove use on incident diarrhea using cross-validated targeted maximum likelihood estimation (CV-TMLE).Results:Households reported using biogas cookstoves in the past 3 d for 23% of observed person-days. The adjusted relative risk of diarrhea for children exposed to biogas cookstove use was 1.31 (95% confidence interval (CI): 1.00, 1.71) compared to unexposed children. The estimated effect of biogas stove use on diarrhea was stronger among breastfed children (2.09; 95% CI: 1.35, 3.25) than for nonbreastfed children and stronger during the dry season (2.03; 95% CI: 1.17, 3.53) than in the wet season. Among children exposed to biogas cookstove use, those with a recent ALRI had the highest mean risk of diarrhea, estimated at 4.53 events (95% CI: 1.03, 8.04) per 1,000 person-days.Discussion:This analysis provides new evidence that child diarrhea may be an unintended health risk of biogas cookstove use. Additional studies are needed to identify exposure pathways of fecal pathogen contamination associated with biodigesters to improve the safety of these widely distributed public health interventions. https://doi.org/10.1289/EHP9468

Effectiveness of interventions to reduce household air pollution from solid biomass fuels and improve maternal and child health outcomes in low- and middle-income countries: A systematic review and meta-analysis.

Interventions to reduce household air pollution (HAP) are key to reducing associated morbidity and mortality in low- and middle- income countries (LMICs); especially among pregnant women and young children. This systematic review aims to determine the effectiveness of interventions aimed to reduce HAP exposure associated with domestic solid biomass fuel combustion, compared to usual cooking practices, for improving health outcomes in pregnant women and children under five in LMIC settings. A systematic review and meta-analysis was undertaken with searches undertaken in MEDLINE, EMBASE, CENTRAL, GIM, ClinicalTrials.gov, and Greenfile in August 2020. Inclusion criteria were experimental, non-experimental, or quasi-experimental studies investigating the impact of interventions to reduce HAP exposure and improve associated health outcomes among pregnant women or children under 5years. Study selection, data extraction, and quality assessment using the Effective Public Health Practice Project tool were undertaken independently by two reviewers. Seventeen out of 7293 retrieved articles (seven pregnancy, nine child health outcome; 13studies) met the inclusion criteria. These assessed improved cookstoves (ICS; n=10studies), ethanol stoves (n=1study), and Liquefied Petroleum Gas (LPG; n=2studies) stoves interventions. Meta-analysis showed no significant effect of ICS interventions compared to traditional cooking for risk of preterm birth (n=2studies), small for gestational age (n=2studies), and incidence of acute respiratory infections (n=6studies). Although an observed increase in mean birthweight was observed, this was not statistically significant (n=4). However, ICS interventions reduced the incidence of childhood burns (n=3; observations=41723; Rate Ratio: 0.66 [95% CI: 0.45-0.96]; I2 : 46.7%) and risk of low birth weight (LBW; n=4; observations=3456; Odds Ratio: 0.73 [95% CI: 0.61-0.87]; I2 : 21.1%). Although few studies reported health outcomes, the data indicate that ICS interventions were associated with reduced risk of childhood burns and LBW. The data highlight the need for the development and implementation of robust, well-reported and monitored, community-driven intervention trials with longer-term participant follow-up.

Association of household solid fuel use and long-term exposure to PM2.5 with arthritis in middle-aged and older population in China: A cohort study

Air pollutants are common modifiable risk factors for arthritis. To explore the longitudinal effects of air pollution on arthritis based on a cohort study in middle-aged and elder people of China. Data was obtained from the China Health and Retirement Longitudinal Study (CHARLS) from 2011 to 2018. A total of 7449 participants aged 45 years and older were involved in our study. The generalized linear mixed models were conducted to examine the separate and joint effects of household air pollution and outdoor air pollution on arthritis, respectively. We found a strong significant association between air pollution and arthritis incidence. Individuals cooking primarily with solid fuel were more likely in higher risk of arthritis compared with cleaner fuel (OR= 1.15; 95% CI: 1.08–1.23). The group-based trajectory model identified four trajectory groups, compared with group “High-Decreasing rapidly”, adjusted ORs of incident arthritis for group “Middle-Decreasing moderately”, “Low-Decreasing slowly” and “Low-Stably” were 1.36 (95% CI, 1.03–1.79), 1.36 (95% CI, 1.01–1.83) and 1.81 (95% CI, 1.30–2.52), respectively. These associations were generally higher in participants younger than 65 years. In addition, solid fuel use and PM2.5 exposure had additive and multiplicative effects on arthritis. The results suggested that solid fuel use and long-term PM2.5 exposure were associated with a higher incidence of arthritis. Therefore, it is necessary to restrict solid fuel use to reduce household air pollution and make stronger environmental protection policies to reduce PM2.5 concentration.