Health effects of household air pollution related to biomass cook stoves in resource limited countries and its mitigation by improved cookstoves

Environmental BaP/BPDE suppressed trophoblast cell invasion/migration and induced miscarriage by down-regulating lnc-HZ01/MEST/VIM axis

Environmental benzo(a)pyrene (BaP) and itsmetabolite benzo(a)pyrene-7, 8-dihydrodiol-9, 10-epoxide (BPDE), classic endocrine disrupting chemical and persistent organic pollutant, could cause miscarriage. However, the detailed mechanisms are still largely unclear and should be further explored. In this study, we discovered that exposure of trophoblast cells with BPDE could suppressed cell invasion/migration by inhibiting MEST/VIM (Vimentin) pathway. Moreover, BPDE exposure also increased lnc-HZ01 expression level, which further inhibited MEST/VIM pathway and then suppressed invasion/migration. Knockdown of lnc-HZ01 or overexpression of MEST could efficiently rescue invasion/migration of BPDE-exposed Swan 71 cells. Furthermore, lnc-HZ01 was highly expressed and MEST/VIM were lowly expressed in recurrent miscarriage (RM) villous tissues compared with healthy control (HC) group. Finally, we also found that BaP exposure inhibited murine Mest/Vim pathway in placental tissues and induced miscarriage in BaP-exposed mice. Therefore, the regulatory mechanisms were similar in BPDE-exposed human trophoblast cells, RM villous tissues, and placental tissues of BaP-exposed mice with miscarriage, building a bridge to connect BaP/BPDE exposure, invasion/migration, and miscarriage. This study provided novel insights in the toxicological effects and molecular mechanisms of BaP/BPDE-induced miscarriage, which is helpful for better elucidating the toxicological risks of BaP/BPDE on female reproduction.

Assessing the health consequences of indoor air pollution from biomass fuel combustion on pediatric populations in rural communities of Pakistan

Indoor air pollution arising from burning of biomass fuels poses a significant threat to child health in rural areas of Pakistan. This cross-sectional study aimed to assess health implications associated with indoor air pollution resulting from biomass burning among children under 12 years of age in rural Punjab. A questionnaire-based survey was conducted in six randomly selected rural districts of Punjab, characterized by their primary reliance on biomass fuels. The findings revealed that several characteristics, such as monthly household income, number of living rooms, secondary use of solid fuels, kitchen type, type of cooking stove, and presence of child in the kitchen with their mother, exhibited significant associations (p < 0.05) with negative health impacts among children. Reported health effects among the children included coughing (18.7%), watery eyes (17.7%), eye irritation (12.3%), runny nose (11.8%), breathing difficulties (8.5%), phlegm (38%), headache (25%), nausea (20.1%), dizziness (6.7%), asthma (6.4%), tuberculosis (1.8%), and pneumonia (1.5%).

An integrated agroforestry-bioenergy system for enhanced energy and food security in rural sub-Saharan Africa

Most people in rural sub-Saharan Africa lack access to electricity and rely on traditional, inefficient, and polluting cooking solutions that have adverse impacts on both human health and the environment. Here, we propose a novel integrated agroforestry-bioenergy system that combines sustainable biomass production in sequential agroforestry systems with biomass-based cleaner cooking solutions and rural electricity production in small-scale combined heat and power plants and estimate the biophysical system outcomes. Despite conservative assumptions, we demonstrate that on-farm biomass production can cover the household's fuelwood demand for cooking and still generate a surplus of woody biomass for electricity production via gasification. Agroforestry and biochar soil amendments should increase agricultural productivity and food security. In addition to enhanced energy security, the proposed system should also contribute to improving cooking conditions and health, enhancing soil fertility and food security, climate change mitigation, gender equality, and rural poverty reduction.

Assessing household fine particulate matter (PM2.5) through measurement and modeling in the Bangladesh cook stove pregnancy cohort study (CSPCS)

Biomass fuel burning is a significant contributor of household fine particulate matter (PM2.5) in the low to middle income countries (LMIC) and assessing PM2.5 levels is essential to investigate exposure-related health effects such as pregnancy outcomes and acute lower respiratory infection in infants. However, measuring household PM2.5 requires significant investments of labor, resources, and time, which limits the ability to conduct health effects studies. It is therefore imperative to leverage lower-cost measurement techniques to develop exposure models coupled with survey information about housing characteristics. Between April 2017 and March 2018, we continuously sampled PM2.5 in three seasonal waves for approximately 48-h (range 46 to 52-h) in 74 rural and semi-urban households among the participants of the Bangladesh Cook Stove Pregnancy Cohort Study (CSPCS). Measurements were taken simultaneously in the kitchen, bedroom, and open space within the household. Structured questionnaires captured household-level information related to the sources of air pollution. With data from two waves, we fit multivariate mixed effect models to estimate 24-h average, cooking time average, daytime and nighttime average PM2.5 in each of the household locations. Households using biomass cookstoves had significantly higher PM2.5 concentrations than those using electricity/liquefied petroleum gas (626 μg/m3 vs. 213 μg/m3). Exposure model performances showed 10-fold cross validated R2 ranging from 0.52 to 0.76 with excellent agreement in independent tests against measured PM2.5 from the third wave of monitoring and ambient PM2.5 from a separate satellite-based model (correlation coefficient, r = 0.82). Significant predictors of household PM2.5 included ambient PM2.5, season, and types of fuel used for cooking. This study demonstrates that we can predict household PM2.5 with moderate to high confidence using ambient PM2.5 and household characteristics. Our results present a framework for estimating household PM2.5 exposures in LMICs, which are often understudied and underrepresented due to resource limitations.

Latin America and the Caribbean Code Against cancer 1st edition: Environment, occupation, and cancer

Within the framework of the Latin America and Caribbean region (LAC) Code Against Cancer 1st edition, the current work presents recommendations to reduce exposure to environmental and occupational carcinogenic agents relevant for LAC. Using the methodology established by the International Agency for Research on Cancer (IARC) in the World Code Against Cancer Framework and experience from developing the European Code Against Cancer 4th edition, a working group of LAC cancer-prevention experts reviewed the list of Group I IARC carcinogenic agents, identified prevalent environmental and occupational exposures in the region, and proposed evidence-based cancer prevention recommendations suited to the epidemiological, socioeconomic, and cultural conditions of LAC countries. Two sets of recommendations were drafted: those targeting the general public and a second set for policymakers. Outdoor and indoor air pollution, ultra-violet radiation and occupational exposures to silica dust, asbestos, benzene, diesel, and welding fumes were identified as prevalent carcinogens in LAC and as agents that could be reduced or eliminated to prevent cancers. Recommendations for additional risk factors were not included due to insufficient data of their attributable burden in LAC (sunbeds, radon, aflatoxin), or lack of a clear preventive action to be taken by the individual (arsenic in drinking water, medical radiation), or lack of evidence of carcinogenicity effect (bisphenol A, phthalates, and pesticides). A broad consensus was reached on environmental and occupational carcinogenic exposures present throughout the LAC region and on individual-level and public policy-level recommendations to reduce or eliminate these exposures. Key educational content for the dissemination of these recommendations was also developed as part of LAC Code Against Cancer 1st Edition.

Reduction of household air pollution through clean fuel intervention and recovery of cellular immune balance

BACKGROUND

We conducted a clean fuel intervention trial (Bangladesh Global Environmental and Occupational Health (GEOHealth) (NCT02824237) with liquefied petroleum gas (LPG) for 26 months among rural Bangladeshi women chronically exposed to household air pollution (HAP) from biomass fuel (BMF) use. We aimed to evaluate the effect of HAP reduction following LPG intervention on immune response outcome.

METHODS

We supplied LPG cook stove and refills in cylinder in 200 households for 26 months. We measured personal exposure to HAP [particulate matter 2.5 (PM2·5), black carbon (BC) and carbon monoxide (CO)] in 200 women (main cook) by personal monitors at pre- and post-intervention. Immune function was assessed before and after intervention, in blood collected within 2 weeks of HAP measurements. Primary endpoints included reduction in HAP, lymphocyte proliferation and oxidative stress response, and alterations in T and B cell proportions.

FINDINGS

Exclusive LPG use for 26 months resulted in significant reduction in PM2·5 (43.5%), BC (13%) and CO (48%) exposure in the women. For one unit decrease in BC, Treg cells and memory B cells increased by 7% and 34% respectively, in the peripheral circulation. One unit decrease in CO was significantly associated with increase in early B cells and plasmablasts by 66% and 5% respectively. For one unit decrease in BC, percent-dividing cells, proliferation and expansion indices increased by 2%, 0.4%, and 1%, respectively.

INTERPRETATION

Reduced personal exposure to HAP through clean fuel intervention was related to a return towards cellular immune balance.

Economic Growth Facilitates Household Fuel Use Transition to Reduce PM2.5-Related Deaths in China

Exposure to ambient and indoor particle matter (PM2.5) leads to millions of premature deaths in China. In recent years, indoor air pollution and premature deaths associated with polluting fuel cooking demonstrate an abrupt decline. However, the driving forces behind the mortality change are still unclear due to the uncertainty in household fuel use prediction. Here, we propose an integrated approach to estimate the fuel use fractions and PM2.5-related deaths from outdoor and indoor sources during 2000-2020 across China. Our model estimated 1.67 and 1.21 million premature deaths attributable to PM2.5 exposure in 2000 and 2020, respectively. We find that the residential energy transition is associated with a substantial reduction in premature deaths from indoor sources, with 100,000 (95% CI: 76,000-122,000) for urban and 265,000 (228,000-300,000) for rural populations during 2000-2020. Economic growth is the dominant driver of fuel use transition and avoids 21% related deaths (357,000, 315,000-402,000) from polluting fuel cooking since 2000, which offsets the adverse impact of ambient emissions contributed by economic growth. Our findings give an insight into the coupled impact of socioeconomic factors in reshaping health burden in exposure pathways.

Bridging the "Know-Do" Gaps in Five Non-Communicable Diseases Using a Common Framework Driven by Implementation Science

According to the United Nations High-Level Meeting 2018, five non-communicable diseases (NCDs) including cardiovascular diseases, chronic respiratory diseases, diabetes mellitus, cancer, and mental health conditions accounted for two-thirds of global deaths. These five NCDs share five common risk factors including tobacco use, unhealthy diets, physical inactivity, alcohol use, and air pollution. Low- and middle-income countries (LMICs) face larger burden of NCDs than high-income countries (HICs), due to differences in ecological, technological, socioeconomic and health system development. Based on high-level evidence albeit mainly from HICs, the burden caused by NCDs can be reduced by affordable medicines and best practices. However, "know-do" gaps, ie, gaps between what we know in science and what we do in practice, has limited the impact of these strategies, especially in LMICs. Implementation science advocates the use of robust methodologies to evaluate sustainable solutions in health, education and social care aimed at informing practice and policies. In this article, physician researchers with expertise in NCDs reviewed the common challenges shared by these five NCDs with different clinical courses. They explained the principles of implementation science and advocated the use of an evidence-based framework to implement solutions focusing on early detection, prevention and empowerment, supplemented by best practices in HICs and LMICs. These successful stories can be used to motivate policymakers, payors, providers, patients and public to co-design frameworks and implement context-relevant, multi-component, evidence-based practices. In pursuit of this goal, we propose partnership, leadership, and access to continuing care as the three pillars in developing roadmaps for addressing the multiple needs during the journey of a person with or at risk of these five NCDs. By transforming the ecosystem, raising awareness and aligning context-relevant practices and policies with ongoing evaluation, it is possible to make healthcare accessible, affordable and sustainable to reduce the burden of these five NCDs.

Assessment of indoor air quality of porous media combustion-based cookstoves

The present study analyzes the emission mitigation ability of a porous media combustion (PMC) technology-based cookstove compared to a free flame combustion (FFC) technology-based cookstove. Emission of pollutants, i.e., PM2.5, PM10, and CO, caused due to burning of fuels, namely, methanol, ethanol, kerosene, and LPG in the kitchen environment are measured. The study incorporated exhaustive real-time indoor air quality (IAQ) measurements and presented the temporal variation of measured pollutant concentrations for 2 h (morning meal duration). In addition, 24 h average concentration of the measured pollutants is also compared with the limits prescribed in WHO guidelines for domestic settings. The results emphasized that the utilization of cookstove based on PMC would help in improving the IAQ of the kitchen area by decreasing the concentrations of PM2.5, PM10, and CO. For 2 h duration measurements, the methanol cookstove based on PMC reduced the concentrations of PM2.5, PM10, and CO by 7.7%, 8.1%, and 17.2%, respectively, compared to FFC cookstove. Similarly, in the case of PMC-based LPG cookstove and kerosene cookstove, the respective values were 11.7%, 20.4%, and 41.6% and 55.3%, 62.6%, and 66.6%. Among all the tested cookstoves, PMC-based LPG cookstove achieved the lowest emission values (PM2.5: 20.6 μg/m³, PM10: 31.3 μg/m³, and CO: 1 ppm) which are lower than the prescribed WHO values (PM2.5: 25 μg/m³, PM10: 50 μg/m³, and CO: 6 ppm).

BPDE exposure promotes trophoblast cell pyroptosis and induces miscarriage by up-regulating lnc-HZ14/ZBP1/NLRP3 axis

Environmental Benzo(a)pyrene (BaP) and its ultimate metabolite BPDE (benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide) are typical persistent organic pollutants and endocrine disrupting chemicals. BaP/BPDE exposure might cause human trophoblast cell dysfunctions and induce miscarriage. However, the underlying mechanisms remain largely elusive. In this study, we found that BPDE exposure induced human trophoblast cell pyroptosis by up-regulating NLRP3/Caspase1/GSDMD pathway. We also identified that lnc-HZ14 was highly expressed in BPDE-exposed trophoblast cells and in recurrent miscarriage (RM) vs healthy control (HC) villous tissues. Lnc-HZ14 promoted trophoblast cell pyroptosis by promoting IRF1-mediated ZBP1 transcription, increasing METTL3-mediated m6A methylation on NLRP3 mRNA and its stability, and also enhancing ZBP1/NLRP3 protein interactions. Knockdown of lnc-HZ14/ZBP1/NLRP3 axis could efficiently alleviate BPDE-induced trophoblast cell pyroptosis. Higher level of pyroptosis, as indicated by the up-regulation of lnc-HZ14/ZBP1/NLRP3 axis, was found in RM vs HC villous tissues. In BaP-exposed mouse model, BaP exposure induced placental tissue pyroptosis and miscarriage by up-regulating murine Zbp1/Nlrp3 axis, and knockdown of Nlrp3 could efficiently reduce placenta pyroptosis and alleviate BaP-induced mouse miscarriage. Serum IL-1β protein level might act as a promising indicator to predict the risk of miscarriage. These findings provided new insights into BaP/BPDE-induced trophoblast cell pyroptosis and miscarriage and might be helpful for further assessment of the toxicological effects of BaP/BPDE on the female reproduction.

Associations between household solid fuel use and activities of daily living trajectories: A nationwide longitudinal study of middle and older adults in China

BACKGROUND

More studies focus on reporting the effects of ambient air pollution on physical activity while ignoring the hazards of indoor air pollution caused by household solid fuel use. Moreover, the impact of individual cognitive and depressive status on the health effects of air pollution is often overlooked.

OBJECTIVE

We examined the association between household solid fuel and activities of daily living (ADL) trajectories, and further examined this association in homogeneous subgroups of cognitive or depressive trajectories.

METHODS

Participants were from the China Health and Retirement Longitudinal Study, which conducted four waves of surveys from 2011 to 2018. We collected information on participants' household fuel use, then the ADL, cognitive and depressive performances were assessed in each wave. The latent growth mixture model (LGMM) was used to identify the optimal trajectory class for ADL, cognition, and depression. Then, the multinomial logistic regression was used to assess the association between solid fuel use and ADL trajectories in total population, as well as subgroups with different cognitive or depression trajectories. Furthermore, we examined the association between switching household fuel types and ADL trajectories across the four-wave survey.

RESULTS

The study sample included 7052 participants. We identified three ADL trajectory classes in total population: "Low-stable", "Moderate-anterior rise", and "Moderate-posterior rise". The multinomial logistic regression results showed that solid fuel use was associated with elevated odds for the adverse ADL trajectories, and this association was still shown in homogeneous subgroups of cognitive or depressive trajectories, while some effects were less significant. In addition, the risk of adverse ADL trajectories generally increases with the times of solid fuel use across the four-wave survey.

CONCLUSIONS

For middle and older adults in China, household solid fuel use was not conducive to physical activity development, which inspires that a further transformation to cleaner fuels is an important intervention.

Physical, chemical and optical properties of PM2.5 and gaseous emissions from cooking with biomass fuel in the Indo-Gangetic Plain

The current study was designed to capture real-world cooking process-wise emissions generated by the combustion of mixed biomass fuel in traditional mud cookstoves in rural kitchens of the north Indian state of Uttar-Pradesh during regular meal preparations. Combustion characteristics, including modified combustion efficiency, thermal efficiency and burn rate, were examined to understand their relationship with emissions. Variations were observed in emission factors (EFs) of PM_2.5, trace gases, namely CO, CO₂, NO_x and SO_2, for different cooking processes. While the highest emission of PM_2.5, CO and SO₂ were observed for boiling (7.0 ± 2.7, 68 ± 29.3, 1.0 ± 1.7 gkg^-1, respectively), CO₂ and NO_x recorded the highest EFs for frying (1537 ± 278.2 & 1.6 ± 0.9 gkg^-1 respectively). Although the study reported similar carbon content emissions for different processes, high EC emissions were observed for baking (1.1 ± 0.3 gkg^-1). A high concentration of K⁺ (indicating biomass burning) and toxic trace metals including Al, Cu, Sr, Ti, Mo & Cd has been reported in the present study. EFs of black carbon and brown carbon from mixed fuel burning during uncontrolled cooking have been discussed for different cooking processes which are critical inputs to emission inventories and radiative forcing calculation. The processes of frying and sautéing were found to be more consistent in emissions of pollutants than boiling and baking (variability- 13 %-167 %). Overall, this study emphasizes that a measurement of combustion characteristics and cooking method type should also be contemplated along with fuel and stove types during field emission studies.

Maternal exposure to ambient PM2.5 and term birth weight: A systematic review and meta-analysis of effect estimates

Effect estimates of prenatal exposure to ambient PM_2.5 on change in grams (β) of birth weight among term births (≥37 weeks of gestation; term birth weight, TBW) vary widely across studies. We present the first systematic review and meta-analysis of evidence regarding these associations. Sixty-two studies met the eligibility criteria for this review, and 31 studies were included in the meta-analysis. Random-effects meta-analysis was used to assess the quantitative relationships. Subgroup analyses were performed to gain insight into heterogeneity derived from exposure assessment methods (grouped by land use regression [LUR]-models, aerosol optical depth [AOD]-based models, interpolation/dispersion/Bayesian models, and data from monitoring stations), study regions, and concentrations of PM_2.5 exposure. The overall pooled estimate involving 23,925,941 newborns showed that TBW was negatively associated with PM_2.5 exposure (per 10 μg/m³ increment) during the entire pregnancy (β = -16.54 g), but with high heterogeneity (I² = 95.6%). The effect estimate in the LUR-models subgroup (β = -16.77 g) was the closest to the overall estimate and with less heterogeneity (I² = 18.3%) than in the other subgroups of AOD-based models (β = -41.58 g; I² = 95.6%), interpolation/dispersion models (β = -10.78 g; I² = 86.6%), and data from monitoring stations (β = -11.53 g; I² = 97.3%). Even PM_2.5 exposure levels of lower than 10 μg/m³ (the WHO air quality guideline value) had adverse effects on TBW. The LUR-models subgroup was the only subgroup that obtained similar significant of negative associations during the three trimesters as the overall trimester-specific analyses. In conclusion, TBW was negatively associated with maternal PM_2.5 exposures during the entire pregnancy and each trimester. More studies based on relatively standardized exposure assessment methods need to be conducted to further understand the precise susceptible exposure time windows and potential mechanisms.

Spirometry parameter alterations due to exposure to indoor air pollutants in rural homes in Bogotá, Colombia

The aim of this study was to determine the association between the concentrations of intradomiciliary PM_2.5, CO, and BC and alterations in respiratory function parameters in a population living in rural dwellings in Bogotá, Colombia. For this cross-sectional study, people were recruited from the rural areas of the localities of Usme and Sumapaz in Bogotá. In total, 68 participants were recruited by means of nonrandom sampling. Indoor air monitoring of PM_2.5, BC, and CO was carried out. Additionally, evaluations of pulmonary function were performed using spirometry. The variables of pulmonary function were included in a multiple linear regression by successive steps and adjusted by the main variables described as modifiers of spirometry parameters, which are age, height, sex, disability, and a history of tobacco use. Assumptions of multicollinearity and the randomization of variances in the residuals were evaluated. Negative associations were found between spirometry parameters and the concentrations of indoor air pollutants. For FEV1/FVC and theoretical FEV1, there was a statistically significant association with the concentration of carbon monoxide (p = 0.003 and 0.019, respectively). The environmental concentrations were higher in homes where biomass was used for cooking, but these differences were statistically significant only for BC and CO (p = 0.008 and 0.03, respectively). The concentrations of carbon monoxide in rural homes were associated with alterations in respiratory function parameters.

World Heart Federation Roadmap for Hypertension - A 2021 Update

The World Heart Federation (WHF) Roadmap series covers a large range of cardiovascular conditions. These Roadmaps identify potential roadblocks and their solutions to improve the prevention, detection and management of cardiovascular diseases and provide a generic global framework available for local adaptation. A first Roadmap on raised blood pressure was published in 2015. Since then, advances in hypertension have included the publication of new clinical guidelines (AHA/ACC; ESC; ESH/ISH); the launch of the WHO Global HEARTS Initiative in 2016 and the associated Resolve to Save Lives (RTSL) initiative in 2017; the inclusion of single-pill combinations on the WHO Essential Medicines' list as well as various advances in technology, in particular telemedicine and mobile health. Given the substantial benefit accrued from effective interventions in the management of hypertension and their potential for scalability in low and middle-income countries (LMICs), the WHF has now revisited and updated the 'Roadmap for raised BP' as 'Roadmap for hypertension' by incorporating new developments in science and policy. Even though cost-effective lifestyle and medical interventions to prevent and manage hypertension exist, uptake is still low, particularly in resource-poor areas. This Roadmap examined the roadblocks pertaining to both the demand side (demographic and socio-economic factors, knowledge and beliefs, social relations, norms, and traditions) and the supply side (health systems resources and processes) along the patient pathway to propose a range of possible solutions to overcoming them. Those include the development of population-wide prevention and control programmes; the implementation of opportunistic screening and of out-of-office blood pressure measurements; the strengthening of primary care and a greater focus on task sharing and team-based care; the delivery of people-centred care and stronger patient and carer education; and the facilitation of adherence to treatment. All of the above are dependent upon the availability and effective distribution of good quality, evidence-based, inexpensive BP-lowering agents.

Household air pollution related to biomass cook stove emissions and its interaction with improved cookstoves

Introduction

Household air pollution (HAP) is associated with significant global morbidity and mortality. Newer initiatives including improved cookstove (IC) and cleaner fuels are being implemented to improve HAP effects.

Methods

A literature review was conducted for household air pollution related to biomass cookstoves in resource limited countries. In January 2018, we electronically searched the PubMed database for the term cookstoves with no date restrictions. We included cohort, case-control, cross-sectional studies, conference abstracts, editorials, and reviews; studies that assessed the emissions related to cookstove and factors affecting HAP emissions.

Results

Twenty-three articles met the objectives of the review. Fine particulate matter with aerodynamic diameter <2.5 µm (PM_2.5), carbon monoxide (CO) and polycyclic aromatic hydrocarbons (PAH) are the major HAP emissions. Emission factors are based on the stove and fuel used while the activity is based on cooking practices. Changes in composition and sources of PM_2.5 causes modification to its resulting toxicity. Many PAHs and their metabolites released by HAP have carcinogenic, teratogenic and mutagenic potential. Improving ventilation decreases concentrations of PM_2.5 and CO in the household air. Few standard tools are available to measure ventilation and continued IC efficacy in long term.

Conclusion

Unavailability of tools to measure ventilation and continued IC efficacy in long term affect uniformity and comparability of IC study results. Community education about the health effects of HAP and importance of ventilation in decreasing HAP is an important aspect of public health policy to prevent HAP effects.

The potential co-benefits for health, economy and climate by substituting raw coal with waste cooking oil as a winter heating fuel in rural households of northern China

The toxic emissions from coal combustion associated with domestic winter heating requirements are an important public health issue. Waste cooking oil (WCO) holds promise as a means of reducing pollutant emissions thereby improving human health with the co-benefit of decreasing climate-forcing gas emissions by avoiding the combustion of mineral coal. With an annual production of ~2.17 Mt of WCO in Northern China, it could be used to meet the winter heating demand of ~3.25 million rural households, offsetting ~9.83 Mt of raw coal consumption. Through the adoption of coal-to-WCO shift in rural regions of 15 provinces, approximately 15.0%, 15.6%, 15.9% and 13.7%, respectively of CO, PM_2.5, SO₂ and NO_X emissions would be eliminated. It is estimated that such a change would remove the respective contributions of these pollutants to the premature deaths of respectively, 63,400, 29,300, 173,00 and 31,300 rural residents. Such a positive health impact on the labor cohort would reduce the loss of labor supply and work time, as well as producing billions of RMB in economic benefits. WCO-based heating technology has the same effect on the reduction of GWC₁₀₀ value as other modern energy carriers while also being cheaper and sustainable, long term. Reducing household emissions by substituting raw coal with green energy is a vital strategy to support pathways for sustainable environment design. The results of this work for the coal-to-WCO shift can reinforce the support for coal phase-out in China.

Biomass-fuelled improved cookstove intervention to prevent household air pollution in Northwest Ethiopia: a cluster randomized controlled trial

Background

Household air pollution from biomass fuels burning in traditional cookstoves currently appeared as one of the most serious threats to public health with a recent burden estimate of 2.6 million premature deaths every year worldwide, ranking highest among environmental risk factors and one of the major risk factors of any type globally. Improved cookstove interventions have been widely practiced as potential solutions. However, studies on the effect of improved cookstove interventions are limited and heterogeneous which suggested the need for further research.

Methods

A cluster randomized controlled trial study was conducted to assess the effect of biomass-fuelled improved cookstove intervention on the concentration of household air pollution compared with the continuation of an open burning traditional cookstove. A total of 36 clusters were randomly allocated to both arms at a 1:1 ratio, and improved cookstove intervention was delivered to all households allocated into the treatment arm. All households in the included clusters were biomass fuel users and relatively homogenous in terms of basic socio-demographic and cooking-related characteristics. Household air pollution was determined by measuring the concentration of indoor fine particulate, and the effect of the intervention was estimated using the Generalized Estimating Equation.

Results

A total of 2031 household was enrolled in the study across 36 randomly selected clusters in both arms, among which data were obtained from a total of 1977 households for at least one follow-up visit which establishes the intention-to-treat population dataset for analysis. The improved cookstove intervention significantly reduces the concentration of household air pollution by about 343 μg/m³ (Ḃ = − 343, 95% CI − 350, − 336) compared to the traditional cookstove method. The overall reduction was found to be about 46% from the baseline value of 859 (95% CI 837–881) to 465 (95% CI 458–472) in the intervention arm compared to only about 5% reduction from 850 (95% CI 828–872) to 805 (95% CI 794–817) in the control arm.

Conclusions

The biomass-fuelled improved cookstove intervention significantly reduces the concentration of household air pollution compared to the traditional method. This suggests that the implementation of these cookstove technologies may be necessary to achieve household air pollution exposure reductions.

Trial registration

The trial project was retrospectively registered on August 2, 2018, at the clinical trials.gov registry database (https://clinicaltrials.gov/) with the NCT03612362 registration identifier number.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12199-020-00923-z.