Assessing personal PM2.5 exposure using a novel neck-mounted monitoring device in rural Rwanda.

There is growing global concern regarding the detrimental health impacts of PM2.5 emissions from traditional stoves that utilize polluting fuels. Conventional methods for estimating daily personal PM2.5 exposure involve personal air samplers and measuring devices placed in a waist pouch, but these instruments are cumbersome and inconvenient. To address this issue, we developed a novel neck-mounted PM2.5 monitoring device (Pocket PM2.5 Logger) that is compact, lightweight, and can operate continuously for 1 week without recharging. Twelve participants who utilized charcoal, firewood, or propane gas for cooking in rural regions of Rwanda wore the Pocket PM2.5 Logger continuously for 1 week, and time-series variations in personal PM2.5 exposure were recorded at 5-min intervals. Individual daily exposure concentrations during cooking differed significantly among users of the different fuel types, and PM2.5 exposure was at least 2.6 and 3.4 times higher for charcoal and firewood users, respectively, than for propane gas users. Therefore, switching from biomass fuels to propane gas would reduce daily individual exposure by at least one-third. An analysis of cooking times showed that the median cooking time per meal was 30 min; however, half the participants cooked for 1.5 h per meal, and one-third cooked for over 4.5 h per meal. Reducing these extremely long cooking times would reduce exposure with all fuel types. The Pocket PM2.5 Logger facilitates the comprehensive assessment of personal PM2.5 exposure dynamics and is beneficial for the development of intervention strategies targeting household air pollution.

High time-resolution measurements of ultrafine and fine woodsmoke aerosol number and surface area concentrations in biomass burning kitchens: A case study in Western Kenya.

Indoor air pollution associated with biomass combustion for cooking remains a significant environmental health challenge in rural regions of sub-Saharan Africa; however, routine monitoring of woodsmoke aerosol concentrations continues to remain sparse. There is a paucity of field data on concentrations of combustion-generated ultrafine particles, which efficiently deposit in the human respiratory system, in such environments. Field measurements of ultrafine and fine woodsmoke aerosol (diameter range: 10-2500 nm) with field-portable diffusion chargers were conducted across nine wood-burning kitchens in Nandi County, Kenya. High time-resolution measurements (1 Hz) revealed that indoor particle number (PN) and particle surface area (PSA) concentrations of ultrafine and fine woodsmoke aerosol are strongly temporally variant, reach exceedingly high levels (PN > 106 /cm3 ; PSA > 104 µm2 /cm3 ) that are seldom observed in non-biomass burning environments, are influenced by kitchen architectural features, and are moderately to poorly correlated with carbon monoxide concentrations. In five kitchens, PN concentrations remained above 105 /cm3 for more than half of the day due to frequent cooking episodes. Indoor/outdoor ratios of PN and PSA concentrations were greater than 10 in most kitchens and exceeded 100 in several kitchens. Notably, the use of metal chimneys significantly reduced indoor PN and PSA concentrations.

Perceptions of long-term impact and change following a midwife-led biomass smoke education program for mothers in rural Uganda: a qualitative study.

INTRODUCTION: Women and children in Uganda and other low- and middle-income countries are exposed to disproportionately high levels of household air pollution from biomass smoke generated by smoke-producing cookstoves, especially in rural areas. This population is therefore particularly vulnerable to the negative health effects caused by household air pollution, including negative pregnancy outcomes and other health issues throughout life. The Midwife Project, a collaboration between research and health teams in the UK and Uganda, began in 2016 to implement an education program on lung health for mothers in Uganda, to reduce the health risks to women and children. Education materials were produced to guide midwives in the delivery of health messages across four rural health centres, and mixed-methods results of knowledge questionnaires and interviews demonstrated knowledge acquisition, acceptability and feasibility. This qualitative follow-up study aimed to improve understanding of the longer term impact of this education program from the perspective of midwives, village health team members and mothers, in consideration of rolling the program out more widely in rural Uganda. METHODS: Purposive sampling was carried out to recruit consenting antenatal or postnatal women, midwives and village health team members who had been involved in an education session. Individual interviews were conducted with 12 mothers and four village health team members, and four focus groups were conducted with 10 midwives in total. Interviews and focus groups were conducted across all four health centres by two researchers and six translators as appropriate depending on language spoken (English or Lusoga). These were semi-structured and directed by topic guides. Reflective and observational notes were also made. A thematic analysis was carried out by two researchers, along with production of a narrative for each mother, to enrich understanding of each individual story. RESULTS: Midwives and village health teams had continued with the program well past the project end date and all mothers expressed making, or intending to make, changes, suggesting long-term feasibility and acceptability. Main themes generated were ability to change and changes made, ability to change dictated by money, importance of practical education, perceived health improvements, and passing on knowledge. Additional findings were that some education topics seemed to be overlooked, and there was a lack of clarity about the village health team role for the purposes of this program. Some mothers had been motivated to overcome financial barriers, for example by reconstructing cooking areas cheaply themselves. However, information given in the program about building advice and potential financial gains was inconsistent. CONCLUSION: Recommendations for future biomass smoke education should include explicit building advice, emphasis on financial gains, encouragement to share the knowledge acquired and clarification of the village health team role. These program changes will improve focus and relevancy, optimise impact and, with behaviour change and implementation strategy in mind, could be used for widespread rollout in rural Uganda. Future research should include quantitative data collection to objectively examine surprising perceived health benefits, including reduction in malaria and burns, and further qualitative work on why some education content appears neglected.

Effect of improved cookstove intervention on childhood acute lower respiratory infection in Northwest Ethiopia: a cluster-randomized controlled trial.

BACKGROUND: Household air pollution exposure is linked with over 3.5 million premature deaths every year, ranking highest among environmental risk factors globally. Children are uniquely vulnerable and sensitive to the damaging health effects of household air pollution which includes childhood acute lower respiratory infection (ALRI). The use of improved cookstoves has been widely encouraged to reduce these health burdens. It is, however, unclear as to whether it is possible to prevent household air pollution-related disease burdens with biomass-fuelled improved cookstove intervention and the evidence regarding its child health effect still attracts wide debate. Therefore, we investigated the child health effect of improved baking stove intervention compared with the continuation of the open burning traditional baking stove. METHODS: A cluster-randomized controlled trial was conducted to assess the health effect of improved baking stove intervention. A total of 100 clusters were randomly allocated to both arms at a 1:1 ratio, and a total of four follow-up visits were carried out within 1 year immediately after the delivery of the intervention to all households allocated into the intervention arm. Data were analyzed in SPSS-22, and the intervention effect was estimated using a Generalized Estimating Equations modeling approach among the intention-to-treat population. RESULTS: A total of 5508 children were enrolled in the study across 100 randomly selected clusters in both arms, among which data were obtained from a total of 5333 participants for at least one follow-up visit which establishes the intention-to-treat population dataset. The intervention was not found to have a statistically significant effect on the longitudinal childhood ALRI with an estimated odds ratio of 0.95 (95% CI: 0.89-1.02). Nevertheless, the longitudinal change in childhood ALRI was significantly associated with age, baseline childhood ALRI, location of cooking quarter, secondary stove type and frequency of baking event measured at baseline. CONCLUSIONS: We found no evidence that an intervention comprising biomass-fuelled improved baking stove reduced the risk of childhood ALRI compared with the continuation of an open burning traditional baking stove. Therefore, effective cooking solutions are needed to avert the adverse health effect of household air pollution, particularly, childhood ALRI. TRIAL REGISTRATION: The trial was registered on August 2, 2018 at clinical trials.gov registry database (registration identifier number: NCT03612362).

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 (B = - 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.

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

BACKGROUND: Household air pollution (HAP) related to cooking is associated with significant global morbidity and mortality. An estimated three billion people worldwide are exposed to cooking related HAP caused by solid fuel combustion. This exposure is highest for the vulnerable population of women and children resulting in significant cumulative health effects. METHODS: A literature review was conducted for health effects of household air pollution related to biomass cookstoves in resource limited countries and to evaluate the effect of improved cookstoves on these health effects. We searched PubMed, Embase and Cochrane Library. We conducted searches in January 2018 with a repeat in February 2020. We included only studies conducted in resource limited countries, published in English, irrespective of publication year and studies that examined the health effects of HAP and/or studied the effects of improved cookstove (IC). Two authors independently screened journal article titles, abstracts and full-text articles to identify those that included the following search term: biomass cookstoves and health risks. We also assessed the limitations of IC with barriers to their uptake. RESULTS: Health effects associated with HAP mostly include increased blood pressure (BP), dyspnea, childhood pneumonia, lung cancer, low birthweight and cardiovascular diseases. Being a global problem with divergent environmental factors including wide variety of fuel used, housing condition, foods prepared, climatic condition and social factors; most solutions though efficient seems inadequate. Improved cookstove (IC) mitigates emissions and improves short term health, though few randomized long-term studies could substantiate its long-standing continuance and health benefits. CONCLUSION: There is ample data about the health effects of HAP, with some benefit with IC intervention for elevated blood pressure, dyspnea symptoms, mutagenicity and cardiovascular diseases. IC does not have any benefit in pregnancy outcomes or children health.

Household air pollution exposure and associations with household characteristics among biomass cookstove users in Puno, Peru.

BACKGROUND: Household air pollution (HAP) from combustion of biomass fuel, such as wood and animal dung, is among the leading environmental risk factors for preventable disease. Close to half of the world's population relies on biomass cookstoves for their daily cooking needs. Understanding factors that affect HAP can inform measures to maximize the effectiveness of cookstove interventions in a cost-effective manner. However, the impact of kitchen and household characteristics, as well as the presence of secondary stoves, on HAP concentrations is poorly understood in Puno, Peru. OBJECTIVE: To explore how household characteristics explain variability of kitchen area concentrations and personal exposures to CO, PM2.5 and BC from biomass cookstoves among women in rural Peru. METHODS: Household characteristics (including kitchen materials and layout, wealth, and cooking behaviors) and HAP measurements were collected from 180 households in Puno, Peru, from baseline measurements of a randomized trial. Kitchen area concentrations and personal exposures to carbon monoxide (CO), fine particulate matter (PM2.5) and black carbon (BC) were sampled for 48 h. We implemented simple and multivariable linear regression models to determine the associations between household characteristics and both kitchen area concentration and personal exposure to each pollutant. RESULTS: Mean daily kitchen area concentrations and personal exposures to HAP were, on average, 48 times above World Health Organization indoor guidelines for PM2.5. We found that roof type explained the most variability in HAP and was strongly associated with both kitchen area concentrations and personal exposures for all pollutants after adjusting for other household variables. Personal exposures were 27%-36% lower for PM2.5, CO and BC, in households with corrugated metal roofs, compared to roofs made of natural materials (straw, totora or reed) after adjusting for other factors. Higher kitchen area concentrations were also associated with less wealth, owning more animals, or sampling during the dry season in multivariable models. Having a liquefied petroleum gas (LPG) stove and having a chimney were associated with lower personal exposures, but were not associated with kitchen area concentrations. Personal exposures were lower by 21% for PM2.5 and 28% for CO and BC concentrations among participants who had both LPG and biomass stoves compared to those with only biomass cookstoves adjusting for other household factors. CONCLUSIONS: Characterizing HAP within different settings can help identify effective and culturally-relevant solutions to reduce HAP exposures. We found that housing roof type is strongly related to kitchen area concentrations and personal exposures to HAP, perhaps because of greater ventilation in kitchens with metal roofs compared to those with thatch roofs. Although HAP concentrations remained above guidelines for all households, promoting use of metal roof materials and LPG stoves may be actionable interventions that can help reduce exposures to HAP in high-altitude rural Peru and similar settings.

Comparing regional stove-usage patterns and using those patterns to model indoor air quality impacts.

Monitoring improved cookstove adoption and usage in developing countries can help anticipate potential health and environmental benefits that may result from household energy interventions. This study explores stove-usage monitor (SUM)-derived usage data from field studies in China (52 stoves, 1422 monitoring days), Honduras (270 stoves, 630 monitoring days), India (19 stoves, 565 monitoring days), and Uganda (38 stoves, 1007 monitoring days). Traditional stove usage was found to be generally similar among four seemingly disparate countries in terms of cooking habits, with average usage of between 171 and 257 minutes per day for the most-used stoves. In Honduras, where survey-based usage data were also collected, there was only modest agreement between sensor data and self-reported user data. For Indian homes, we combined stove-usage data with a single-zone Monte Carlo box model to estimate kitchen-level PM2.5 and CO concentrations under various scenarios of cleaner cookstove adoption. We defined clean cookstove performance based on the International Standards Organization (ISO) voluntary guidelines. Model results showed that even with 75% displacement of traditional stoves with the cleanest available stove (ISO tier-5), World Health Organization 24 hours PM2.5 standards were exceeded in 96.4% of model runs, underscoring the importance of full displacement.

Impacts of stove/fuel use and outdoor air pollution on chemical composition of household particulate matter.

Biomass combustion for cooking and heating releases particulate matter (PM2.5 ) that contributes to household air pollution. Fuel and stove types affect the chemical composition of household PM, as does infiltration of outdoor PM. Characterization of these impacts can inform future exposure assessments and epidemiologic studies, but is currently limited. In this study, we measured chemical components of PM2.5 (water-soluble organic matter [WSOM], ions, black carbon, elements, organic tracers) in rural Chinese households using traditional biomass stoves, semi-gasifier stoves with pelletized biomass, and/or non-biomass stoves. We distinguished households using one stove type (traditional, semi-gasifier, or LPG/electric) from those using multiple stoves/fuels. WSOM concentrations were higher in households using only semi-gasifier or traditional stoves (31%-33%) than in those with exclusive LPG/electric stove (13%) or mixed stove use (12%-22%). Inorganic ions comprised 14% of PM in exclusive LPG/electric households, compared to 1%-5% of PM in households using biomass. Total PAH content was much higher in households that used traditional stoves (0.8-2.8 mg/g PM) compared to those that did not (0.1-0.3 mg/g PM). Source apportionment revealed that biomass burning comprised 27%-84% of PM2.5 in households using biomass. In all samples, identified outdoor sources (vehicles, dust, coal combustion, secondary aerosol) contributed 10%-20% of household PM2.5 .

Nitrogen dioxide exposures from biomass cookstoves in the Peruvian Andes.

BACKGROUND: Household air pollution from biomass cookstoves is a major contributor to global morbidity and mortality, yet little is known about exposures to nitrogen dioxide (NO2 ). OBJECTIVE: To characterize NO2 kitchen area concentrations and personal exposures among women with biomass cookstoves in the Peruvian Andes. METHODS: We measured kitchen area NO2 concentrations at high-temporal resolution in 100 homes in the Peruvian Andes. We assessed personal exposure to NO2 in a subsample of 22 women using passive samplers. RESULTS: Among 97 participants, the geometric mean (GM) highest hourly average NO2 concentration was 723 ppb (geometric standard deviation (GSD) 2.6) and the GM 24-hour average concentration was 96 ppb (GSD 2.6), 4.4 and 2.9 times greater than WHO indoor hourly (163 ppb) and annual (33 ppb) guidelines, respectively. Compared to the direct-reading instruments, we found similar kitchen area concentrations with 48-hour passive sampler measurements (GM 108 ppb, GSD 3.8). Twenty-seven percent of women had 48-hour mean personal exposures above WHO annual guidelines (GM 18 ppb, GSD 2.3). In univariate analyses, we found that roof, wall, and floor type, as well as higher SES, was associated with lower 24-hour kitchen area NO2 concentrations. PRACTICAL IMPLICATIONS: Kitchen area concentrations and personal exposures to NO2 from biomass cookstoves in the Peruvian Andes far exceed WHO guidelines. More research is warranted to understand the role of this understudied household air pollutant on morbidity and mortality and to inform cleaner-cooking interventions for public health.

Noncommunicable Respiratory Disease and Air Pollution Exposure in Malawi (CAPS). A Cross-Sectional Study.

RATIONALE: Noncommunicable respiratory diseases and exposure to air pollution are thought to be important contributors to morbidity and mortality in sub-Saharan African adults. OBJECTIVES: We set out to explore the prevalence and determinants of noncommunicable respiratory disease among adults living in Chikhwawa District, Malawi. METHODS: We performed a cross-sectional study among adults in communities participating in a randomized controlled trial of a cleaner-burning biomass-fueled cookstove intervention (CAPS [Cooking and Pneumonia Study]) in rural Malawi. We assessed chronic respiratory symptoms, spirometric abnormalities, and personal exposure to air pollution (particulate matter <2.5 µm in aerodynamic diameter [PM2.5] and carbon monoxide [CO]). Weighted prevalence estimates were calculated; multivariable and intention-to-treat analyses were done. MEASUREMENTS AND MAIN RESULTS: One thousand four hundred eighty-one participants (mean [SD] age, 43.8 [17.8] yr; 57% female) were recruited. The prevalence of chronic respiratory symptoms, spirometric obstruction, and restriction were 13.6% (95% confidence interval [CI], 11.9-15.4), 8.7% (95% CI, 7.0-10.7), and 34.8% (95% CI, 31.7-38.0), respectively. Median 48-hour personal PM2.5 and CO exposures were 71.0 µg/m3 (interquartile range [IQR], 44.6-119.2) and 1.23 ppm (IQR, 0.79-1.93), respectively. Chronic respiratory symptoms were associated with current/ex-smoking (odds ratio [OR], 1.59; 95% CI, 1.05-2.39), previous tuberculosis (OR, 2.50; 95% CI, 1.04-15.58), and CO exposure (OR, 1.46; 95% CI, 1.04-2.05). Exposure to PM2.5 was not associated with any demographic, clinical, or spirometric characteristics. There was no effect of the CAPS intervention on any of the secondary trial outcomes. CONCLUSIONS: The burden of chronic respiratory symptoms, abnormal spirometry, and air pollution exposures in adults in rural Malawi is of considerable potential public health importance. We found little evidence that air pollution exposures were associated with chronic respiratory symptoms or spirometric abnormalities and no evidence that the CAPS intervention had effects on the secondary trial outcomes. More effective prevention and control strategies for noncommunicable respiratory disease in sub-Saharan Africa are needed. Clinical trial registered with www.isrctn.com (ISRCTN 59448623).

Prevalence and risk factors of acute lower respiratory infection among children living in biomass fuel using households: a community-based cross-sectional study in Northwest Ethiopia.

BACKGROUND: Childhood acute lower respiratory infection in the form of pneumonia is recognized as the single largest cause of childhood death globally accounting for 16% of the overall deaths. Some studies also reported a higher prevalence of childhood acute respiratory infection in Ethiopia, which ranges from 16% up to 33.5%. Concerning the risk factors, there are limited community-based studies in Ethiopia in general, and in the current study region in particular. Therefore, the present study was conducted to investigate the prevalence of childhood acute respiratory infection and associated factors in Northwest Ethiopia. METHODS: As part of the wider stove trial project, a cross-sectional study was conducted in May 2018 among a total of 5830 children aged less than 4 years old in randomly selected clusters. Binary logistic regression was applied to identify factors linked with childhood acute lower respiratory infection and adjusted odds ratios were used as measures of effect with a 95% confidence interval. RESULTS: A total of 5830 children were included in the study within 100 clusters. Out of which 51.7% were male and 48.3% female. The prevalence of childhood lower acute respiratory infection was 19.2% (95% CI: 18.2-20.2) and found to decrease among children living in homes with chimney, eaves space and improved cookstove than children living in households with no chimney, eaves space and improved cookstove with estimated AOR of 0.60 (95% CI: 0.51-0.70), 0.70 (95% CI: 0.60-0.84) and 0.43 (95% CI: 0.28-0.67) respectively. It was also associated with other cooking-related factors such as cow dung fuel use [AOR = 1.54 (95% CI: 1.02-2.33)], child spending time near stove during cooking [AOR = 1.41 (95% CI: 1.06-1.88), presence of extra indoor burning events [AOR = 2.19 (95% CI: 1.41-3.40)] and with frequent cooking of meals [AOR = 1.55 (95% CI: 1.13-2.13)]. CONCLUSION: High prevalence of childhood acute lower respiratory infection was demonstrated by this study and it was found to be associated with household ventilation, cooking technology, and behavioral factors. Therefore, we recommend a transition in household ventilation, cooking technologies as well as in child handling and in the peculiar local extra indoor burning practices.

Facilitators and barriers to improved cookstove adoption: a community-based cross-sectional study in Northwest Ethiopia.

BACKGROUND: Among the environmental risk factors, household air pollution exposure from traditional cooking practices is one of the biggest killers globally, which mainly impacts developing countries where many families rely on traditional cooking practices. Although improved cookstove adoption is central to tackle this public health issue, the efforts to disseminate cookstove technologies have faced challenges, and the adoption rates are reported to be very low in many developing countries including Ethiopia. Therefore, this study aimed to determine the magnitude and identify potential factors that may act as facilitators or barriers to adoption from users' point of view. METHODS: As part of the wider stove trial project, a cross-sectional study was conducted among a total of 5830 households under randomly selected clusters. The required data were collected through face-to-face interviews, and a backward stepwise logistic regression analysis technique was applied to evaluate the effect of potential predictor variables on adoption using adjusted odds ratio (AOR) as measures of effect. RESULTS: The prevalence of adoption was found to be 12.3% (95% CI 11.5-13.2), and households headed by females (AOR 1.96; 95% CI 1.24-3.10), private house ownership (AOR 4.58; 95% CI 3.89-6.19), separate cooking location (AOR 1.84; 95% CI 1.49-2.78), fuel purchasing (AOR 2.13; 95% CI 1.64-2.76), health benefit (AOR 1.76; 95% CI 1.15-2.70), optimistic social interaction (AOR 1.81; 95% CI 1.46-2.26), traditional suitability (AOR 1.58; 95% CI 1.28-1.95), stove use demonstration experience (AOR 2.47; 95% CI 1.98-3.07), cheap price (AOR 2.48; 95% CI 1.91-3.21), availability (AOR 1.81; 95% CI 1.5-1, 2.17), fuel-saving benefit (AOR 1.63; 95% CI 1.18-2.24), and more durable stove (AOR 1.71; 95% CI 1.30-2.26) of cookstove played a significant role as facilitators to adoption. In addition, lower educational level of head (AOR 0.31; 95% CI 0.23-0.42) and fuel processing requirement (AOR 0.55; 95% CI 0.44-0.70) of cookstove were found to be barriers for adoption. CONCLUSIONS: Extremely lower improved cookstove adoption was observed due to household- and setting-related, cookstove technology-related, user knowledge- and perception-related, and financial- and market development-related factors. Therefore, to gain successful adoption, implementers and policymakers should consider those important factors in the implementation of clean cooking solutions to the community.

Longitudinal evaluation of a household energy package on blood pressure, central hemodynamics, and arterial stiffness in China.

BACKGROUND: Cardiovascular diseases are the leading contributors to disease burden in China and globally, and household air pollution exposure is associated with risk of cardiovascular disease. OBJECTIVES: We evaluated whether subclinical cardiovascular outcomes in adult Chinese women would improve after distribution of an energy package comprised of a semi-gasifier cookstove, water heater, chimney, and supply of processed biomass fuel. METHODS: We enrolled 204 households (n = 205 women) from 12 villages into a controlled before- and after-intervention study on cardiovascular health and air pollution in Sichuan Province. The intervention was distributed to 124 households during a government-sponsored rural energy demonstration program. The remaining 80 households received the package 18 months later at the end of the study, forming a comparison group. One woman from each household had their blood pressure (BP), central hemodynamics, and arterial stiffness measured along with exposures to air pollution and demographic and household characteristics, on up to five visits. We used a difference-in-differences mixed-effects regression approach with Bayesian inference to assess the impact of the energy package on sub-clinical cardiovascular outcomes. RESULTS: Women who did not receive the energy package had greater mean decreases in brachial systolic (-4.1 mmHg, 95% credible interval (95%CIe) -7.3, -0.9) and diastolic BP (-2.0 mmHg, 95%CIe -3.6, -0.5) compared with women who received the package (systolic: -2.7, 95%CIe -5.0, -0.4; diastolic: -0.3, 95%CIe -1.4, 0.8) resulting in slightly positive but not statistically significant difference-in-differences effect estimates of 1.3 mmHg (95%CIe -2.5, 5.2) and 1.7 mmHg (95%CIe -0.3, 3.6), respectively. Similar trends were found for central BP, central pulse pressure, and arterial stiffness. Air pollution exposures decreased on average for both treatment groups, with a greater range of reductions among women who did not receive the package (with package: -30% to -50%; without package: +2% to -69%), likely as a result of increased use of gas fuel and electric stoves among this group. Outdoor air quality changed very little over time. CONCLUSIONS: Gasifier stoves have been widely promoted as the next generation of 'clean-cooking' technologies, however their effectiveness in improving health in real-world settings should be carefully evaluated and communicated before scaling up their implementation.

Usage and impacts of the Envirofit HM-5000 cookstove.

Burning solid fuels to fulfill daily household energy needs results in chronic exposure to household air pollution (HAP), which is among the world's greatest health risks. This paper presents the results of a cross-sectional study of cookstove usage, fuel consumption, and indoor PM2.5 concentrations in rural and urban Honduran homes cooking with the Envirofit HM-5000 metal plancha stove (n = 32) as compared to control households using baseline cooking technologies (n = 33). Temperature-based stove usage measurements showed high HM-5000 acceptance, with significant displacement of the traditional cookstoves at both the urban (99%, P < .05) and rural study sites (75%, P < .05). However, longer-term usage data collected in peri-urban households showed that participants cooked on the HM-5000 more frequently during the 3-day monitoring period than during the following 3 weeks. Average indoor PM2.5 was 66% lower in HM-5000 households as compared to control households (P < .05). Lower indoor PM2.5 concentrations observed in participant homes as compared to control households, supported by high usage and traditional stove displacement, suggest the potential for the HM-5000 to yield health improvements in adopting Honduran households.

Randomized Controlled Ethanol Cookstove Intervention and Blood Pressure in Pregnant Nigerian Women.

RATIONALE: Hypertension during pregnancy is a leading cause of maternal mortality. Exposure to household air pollution elevates blood pressure (BP). OBJECTIVES: To investigate the ability of a clean cookstove intervention to lower BP during pregnancy. METHODS: We conducted a randomized controlled trial in Nigeria. Pregnant women cooking with kerosene or firewood were randomly assigned to an ethanol arm (n = 162) or a control arm (n = 162). BP measurements were taken during six antenatal visits. In the primary analysis, we compared ethanol users with control subjects. In subgroup analyses, we compared baseline kerosene users assigned to the intervention with kerosene control subjects and compared baseline firewood users assigned to ethanol with firewood control subjects. MEASUREMENTS AND MAIN RESULTS: The change in diastolic blood pressure (DBP) over time was significantly different between ethanol users and control subjects (P = 0.040); systolic blood pressure (SBP) did not differ (P = 0.86). In subgroup analyses, there was no significant intervention effect for SBP; a significant difference for DBP (P = 0.031) existed among preintervention kerosene users. At the last visit, mean DBP was 2.8 mm Hg higher in control subjects than in ethanol users (3.6 mm Hg greater in control subjects than in ethanol users among preintervention kerosene users), and 6.4% of control subjects were hypertensive (SBP ≥140 and/or DBP ≥90 mm Hg) versus 1.9% of ethanol users (P = 0.051). Among preintervention kerosene users, 8.8% of control subjects were hypertensive compared with 1.8% of ethanol users (P = 0.029). CONCLUSIONS: To our knowledge, this is the first cookstove randomized controlled trial examining prenatal BP. Ethanol cookstoves have potential to reduce DBP and hypertension during pregnancy. Accordingly, clean cooking fuels may reduce adverse health impacts associated with household air pollution. Clinical trial registered with www.clinicaltrials.gov (NCT02394574).

Enhancing LPG adoption in Ghana (ELAG): a factorial cluster-randomized controlled trial to Enhance LPG Adoption & Sustained use.

BACKGROUND: Three billion individuals worldwide rely on biomass fuel [dung, wood, crops] for cooking and heating. Further, health conditions resulting from household air pollution (HAP) are responsible for approximately 3.9 million premature deaths each year. Though transition away from traditional biomass stoves is projected curb the health effects of HAP by mitigating exposure, the benefits of newer clean cookstove technologies can only be fully realized if use of these new stoves is exclusive and sustained. However, the conditions under which individuals adopt and sustain use of clean cookstoves is not well understood. METHODS: The Enhancing LPG Adoption in Ghana (ELAG) study is a cluster-randomized controlled trial employing a factorial intervention design. The first component is a behavior change intervention based on the Risks, Attitudes, Norms, Abilities, and Self-regulation (RANAS) model. This intervention seeks to align these five behavioral factors with clean cookstove adoption and sustained use. A second intervention is access-related and will improve LPG availability by offering a direct-delivery refueling service. These two interventions will be integrated via a factorial design whereby 27 communities are assigned to one of the following: the control arm, the educational intervention, the delivery, or a combined intervention. Intervention allocation is determined by a covariate-constrained randomization approach. After intervention, approximately 900 households' individual fuel use is tracked for 12 months via iButton stove use monitors. Analysis will include hierarchical linear models used to compare intervention households' fuel use to control households. DISCUSSION: Literature to-date demonstrates that recipients of improved cookstoves rarely completely adopt the new technology. Instead, they often practice partial adoption (fuel stacking). Consequently, interventions are needed to influence adoption patterns and simultaneously to understand drivers of fuel adoption. Ensuring uptake, adoption, and sustained use of improved cookstove technologies can then lead to HAP-reductions and consequent improvements in public health. TRIAL REGISTRATION: NCT03352830 (November 24, 2017).

Associations between household air pollution and reduced lung function in women and children in rural southern India.

Half of the world's population still relies on solid fuels to fulfill its energy needs for cooking and space heating, leading to high levels of household air pollution (HAP), adversely affecting human health and the environment. A cross-sectional cohort study was conducted to investigate any associations between: (1) HAP metrics (mass concentration of particulate matter of aerodynamic size less than 2.5 µm (PM2.5 ), lung-deposited surface area (LDSA) and carbon monoxide (CO)); (2) a range of household and socio-demographic characteristics; and (3) lung function for women and children exposed daily to biomass cookstove emissions, in rural southern India. HAP measurements were collected inside the kitchen of 96 households, and pulmonary function tests were performed for the women and child in each enrolled household. Detailed questionnaires captured household characteristics, health histories and various socio-demographic parameters. Simple linear and logistic regression analysis was performed to examine possible associations between the HAP metrics, lung function and all household/socio-demographic variables. Obstructive lung defects (forced vital capacity (FVC) ≥ lower limit of normal (LLN) and forced expiratory volume in 1 second (FEV1 )/FVC < LLN) were found in 8% of mothers and 9% of children, and restrictive defects (FVC < LLN and FEV1 /FVC ≥ LLN) were found in 17% of mothers and 15% of children. A positive association between LDSA, included for the first time in this type of epidemiological study, and lung function was observed, indicating LDSA is a superior metric compared to PM2.5 to assess effects of PM on lung function. HAP demonstrated a moderate association with subnormal lung function in children. The results emphasize the need to look beyond mass-based PM metrics to assess fully the association between HAP and lung function.

Mutagenicity of particle emissions from solid fuel cookstoves: A literature review and research perspective.

Household solid fuel use is a major source of many air pollutants causing severe air pollution and adverse health outcomes. In evaluation of health impacts of household air pollution, it is essential to characterize toxic properties like mutagenicity of residential fuel combustion emissions and exposure assessments. Mutagenicity of emissions from solid fuel cookstoves were analyzed through a literature review. T98 and TA100 strains are two most widely used strains in mutagenic Ames test, and results for these two strains are generally positively correlated though they have different endpoints. Direct and indirect mutagenic activities are positively correlated, and statistically insignificantly different though indirect mutagenic emissions are apparently higher. Mutagenicity emission factors on the basis of fuel energy (MJ) or useful energy delivered (MJd) for solid fuel cookstoves vary in nearly 3 orders of magnitude, ranging from 3.0×104 rev./MJd to 1.8×107 rev./MJd (or 1.1×104 rev./MJ to 4.2×106 rev./MJ). Low mutagenic emissions are reported for high efficiency stoves such as a forced-draft one. Mutagenicity emission factors are positively correlated with emissions of PM2.5. Relationship between mutagenicity and polycyclic aromatic hydrocarbons (PAHs) emissions is inconsistent among studies as PAHs are minor fractions of toxic organics contributing to the total mutagenicity. Generally, studies on mutagenicity of emissions from household cookstoves are very limited, and future studies are encouraged on mutagenic emissions from different fuel types and household stoves, evaluation of mutagenic activities of both gaseous and particulate emissions, and toxicology and exposure assessments of household air pollution.

Kerosene lighting contributes to household air pollution in rural Uganda.

The literature on the contribution of kerosene lighting to indoor air particulate concentrations is sparse. In rural Uganda, kitchens are almost universally located outside the main home, and kerosene is often used for lighting. In this study, we obtained longitudinal measures of particulate matter 2.5 microns or smaller in size (PM2.5 ) from living rooms and kitchens of 88 households in rural Uganda. Linear mixed-effects models with a random intercept for household were used to test the hypotheses that primary reported lighting source and kitchen location (indoor vs outdoor) are associated with PM2.5 levels. During initial testing, households reported using the following sources of lighting: open-wick kerosene (19.3%), hurricane kerosene (45.5%), battery-powered (33.0%), and solar (1.1%) lamps. During follow-up testing, these proportions changed to 29.5%, 35.2%, 18.2%, and 9.1%, respectively. Average ambient, living room, and kitchen PM2.5 levels were 20.2, 35.2, and 270.0 µg/m3 . Living rooms using open-wick kerosene lamps had the highest PM2.5 levels (55.3 µg/m3 ) compared to those using solar lighting (19.4 µg/m3 ; open wick vs solar, P=.01); 27.6% of homes using open-wick kerosene lamps met World Health Organization indoor air quality standards compared to 75.0% in homes using solar lighting.