Improved cookstoves to reduce household air pollution exposure in sub-Saharan Africa: A scoping review of intervention studies.

Household air pollution (HAP), primarily from biomass fuels used for cooking, is associated with adverse health outcomes and premature mortality. It affects almost half of the world's population, especially in low-income and low-resourced communities. However, many of the 'improved' biomass cookstoves (ICS) aimed at reducing HAP lack empirical evidence of pollutant reduction and reliability in the field. A scoping review guided by the Joanna Briggs Institute framework was systematically conducted to explore and analyse the characteristics of cookstoves to assess the ICS available to meet the socio-economic and health needs of households in sub-Sahara Africa (sSA). The review searched Scopus, PubMed, Web of Science, EMBASE, Global Health Database on OVID, BASE, and conducted a grey literature search from 2014 to 2022 for all field-based ICS studies. In addition, user perspectives were explored for cookstoves analysed as available, affordable, and effective in reducing harmful biomass emissions. The search returned 1984 records. Thirty-three references containing 23 ICS brands were included. The cookstoves were analysed into seven categories: (1) efficiency in HAP reduction, (2) availability, (3) affordability, (4) sustainability, (5) safety, (6) health outcomes, and (7) user experience. Most (86.9%) of the improved cookstoves showed a reduction in harmful emission levels compared to the traditional three-stone fire. However, the levels were higher than the WHO-recommended safe levels. Only nine were priced below 40 USD. Users placed emphasis on cookstoves' suitability for cooking, fuel and time savings, safety, and price. Equality in cooking-related gender roles and psychosocial benefits were also reported. The review demonstrated limited field testing, a lack of evidence of ICS emissions in real-life settings in sSA, heterogeneity in emission measurements, and incomplete descriptions of ICS and kitchen features. Gender differences in exposure and psychosocial benefits were also reported. The review recommends improved cookstove promotion alongside additional measures to reduce HAP at a cost affordable to low-resource households. Future research should focus on detailed reporting of study parameters to facilitate effective comparison of ICS performance in different social settings with different local foods and fuel types. Finally, a more community-based approach is needed to assess and ensure user voices are represented in HAP intervention studies, including designing the cookstoves.

Which Biomass Stove(s) Capable of Reducing Household Air Pollution Are Available to the Poorest Communities Globally?

Globally, household and ambient air pollution (HAAP) leads to approximately seven million premature deaths per year. One of the main sources of household air pollution (HAP) is the traditional stove. So-called improved cookstoves (ICS) do not reduce emissions to levels that benefit health, but the poorest communities are unlikely to have access to cleaner cooking in the medium term. Therefore, ICS are being promoted as an intermediate step. This paper summarises the current evidence on the ICS available to the global poorest, utilising data from the Clean Cookstoves Catalog and systematic review evidence from the field. The cheapest stoves offer little reduction in HAP. Only one ICS, available at US$5 or less, (the canarumwe) minimally reduced pollutants based on ISO testing standards and no studies included in the systematic reviews reported tested this stove in the field. We recommend field testing all ICS as standard, and clear information on stove characteristics, sustainability, safety, emissions efficiency, in-field performance, affordability, availability in different settings, and the ability of the stove to meet community cooking needs. In addition, ICS should be promoted alongside a suite of measures, including improved ventilation and facilities to dry wood, to further reduce the pollutant levels.

Do improved biomass cookstove interventions improve indoor air quality and blood pressure? A systematic review and meta-analysis.

OBJECTIVES: This systematic review and meta-analysis evaluates the most recent evidence to examine whether use of improved biomass cookstoves in households in low-middle income countries results in reduction in mean concentrations of carbon monoxide (CO) and particulate matter of size 2.5 µm (PM2.5) in the cooking area, as well as reduction in mean systolic (SBP) and diastolic blood pressure (DBP) of adults using the cookstoves when compared to adults who use traditional three stone fire or traditional biomass cookstoves. METHODS: We searched databases of scientific and grey literature. We included studies if published between January 2012 and June 2021, reported impact of ICS interventions in non-pregnant adults in low/middle-income countries, and reported post-intervention results along with baseline of traditional cookstoves. Outcomes included 24- or 48-h averages of kitchen area PM2.5, CO, mean SBP and DBP. Meta-analyses estimated weighted mean differences between baseline and post-intervention values for all outcome measures. RESULTS: Eleven studies were included; ten contributed estimates for HAP and four for BP. Interventions lead to significant reductions in PM2.5 (-0.73 mg/m3, 95% CI: -1.33, -0.13), CO (-8.37 ppm, 95%CI: -13.20, -3.54) and SBP (-2.82 mmHg, 95% CI: -5.53, -0.11); and a non-significant reduction in DBP (-0.80 mmHg, 95%CI: -2.33, 0.73), when compared to baseline of traditional cookstoves. Except for DBP, greatest reductions in all outcomes came from standard combustion ICS with a chimney, compared to ICS without a chimney and advanced combustion ICS. CONCLUSION: Among the reviewed biomass stove types, ICS with a chimney feature resulted in greatest reductions in HAP and BP.

A Review of Permeability and Flow Simulation for Liquid Composite Moulding of Plant Fibre Composites.

Liquid composite moulding (LCM) of plant fibre composites has gained much attention for the development of structural biobased composites. To produce quality composites, better understanding of the resin impregnation process and flow behaviour in plant fibre reinforcements is vital. By reviewing the literature, we aim to identify key plant fibre reinforcement-specific factors that influence, if not govern, the mould filling stage during LCM of plant fibre composites. In particular, the differences in structure (physical and biochemical) for plant and synthetic fibres, their semi-products (i.e., yarns and rovings), and their mats and textiles are shown to have a perceptible effect on their compaction, in-plane permeability, and processing via LCM. In addition to examining the effects of dual-scale flow, resin absorption, (subsequent) fibre swelling, capillarity, and time-dependent saturated and unsaturated permeability that are specific to plant fibre reinforcements, we also review the various models utilised to predict and simulate resin impregnation during LCM of plant fibre composites.

Parents' perceptions of unintentional paediatric burn injuries - A qualitative study.

BACKGROUND: Burn injuries disproportionally affect the world's poorest populations. However, there has been a lack of research that has investigated the social, cultural or contextual factors associated with this injury mechanism in these areas. As a result, there is a scarcity of information from which to develop culturally appropriate and targeted burn prevention initiatives. METHODS: A community survey was used to identify households to take part in this qualitative study. Semi-structured interviews were conducted with 32 parents from four different villages in Malawi to discuss their experiences of burn injuries sustained by children in the household as well as any existing preventative strategies used. In addition, 29 of the study households took part in an observation exercise to identify and discuss burn hazards present around the home environment. Transcripts and observations were recorded and transcribed verbatim. A thematic approach was used to analyse the data. RESULTS: The final themes could be categorised into three key areas: parental perception of hazards around the home; socio-cultural and developmental factors associated with burn injuries; and parental perception of burns prevention. Factors associated with unintentional burn injuries, as perceived by parents, included: increased exposure to hazards, children's play and development activities, increased fire use during the morning hours and the children's household roles and responsibilities. Although some parents identified possible burns prevention strategies numerous barriers to prevention were highlighted including: poverty, poor housing infrastructure and restrictions, knowledge deficit, inability to provide adequate supervision and the child's behaviour. CONCLUSIONS: Parents recognise that there are a number of burn hazards and risks present around the home however factors that prevented them acting included: a lack of knowledge about injury prevention, a lack of household safety equipment, a lack of control to make alternations to their housing and an inability to adequately supervise their children. In the future it is crucial that the local context and community are consulted in the development of any future burn injury prevention strategies to ensure that they are appropriate, accepted and effective.

Toilet training: what can the cookstove sector learn from improved sanitation promotion?

Within the domain of public health, commonalities exist between the sanitation and cookstove sectors. Despite these commonalities and the grounds established for cross-learning between both sectors, however, there has not been much evidence of knowledge exchange across them to date. Our paper frames this as a missed opportunity for the cookstove sector, given the capacity for user-centred innovation and multi-scale approaches demonstrated in the sanitation sector. The paper highlights points of convergence and divergence in the approaches used in both sectors, with particular focus on behaviour change approaches that go beyond the level of the individual. The analysis highlights the importance of the enabling environment, community-focused approaches and locally specific contextual factors in promoting behavioural change in the sanitation sector. Our paper makes a case for the application of such approaches to cookstove interventions, especially in light of their ability to drive sustained change by matching demand-side motivations with supply-side opportunities. Abbreviation: DALY: Disability-adjusted life year; CHC: Community Health Club; CLTS: Community-Led Total Sanitation; HAP: Household air pollution; BM-WASH: Integrated Behavioural Model for Water, Sanitation and Hygiene; ICS: Improved cookstove; LPG: Liquefied petroleum gas; NBA: Nirmal Bharat Abhiyan; NGO: Non:governmental organisation; OD: Open defecation; ODF: Open defecation free; HAST: Participatory Hygiene and Sanitation Transformation; RANAS: Risks, Attitudes, Norms, Abilities and Self-regulation RCT: Randomised controlled trial; (Sani) FOAM: Focus, Opportunity, Ability and Motivation; SBM: Swachh Bharat Mission; TSC: Total Sanitation Campaign; WASH: Water, Sanitation and Hygiene.

Effects of processing on the polyphenol and phenolic acid content and antioxidant capacity of semi-dried cherry tomatoes (Lycopersicon esculentum M.).

BACKGROUND: This study was performed to test the effects of pre-treating cherry tomatoes with a solution containing citric acid-NaCl-CaCl2 (10:10:24 g L(-1)), followed by one of three different drying regimes (40, 60, 80 °C) on the antioxidant capacity of their aqueous extracts and the extent of phenolic compound degradation. RESULTS: Chlorogenic acids, caffeic acid, ferulic acid, rutin and naringenin were all detected in the aqueous extracts. In fresh cherry tomatoes the predominant phenolic compound was rutin, followed by naringenin, which corresponded to 79% and 8% of the total phenolic compounds present, respectively. Pre-treatment was protective towards naringenin and had a modest protective effect on rutin and ferulic acid (0.1 > P > 0.05). Total phenolic content was similar in all samples, but there was a trend for the level of free polyphenols to be lower in treated tomatoes. The destruction of naringenin was confirmed by liquid chromatographic-mass spectrometric data. CONCLUSION: A significant effect of temperature on the antioxidant capacity was observed. After this treatment the industry might introduce some advances in the processing of tomatoes, preserving the main nutritive characteristics and saving the products as semi-dried.

A systematic study of carboxylic acids in negative ion mode electrospray ionisation mass spectrometry providing a structural model for ion suppression.

We report a systematic investigation of the effects and structural requirements for ion suppression in negative ion mode electrospray ionisation mass spectrometry of a series of carboxylic acids and present a structural model rationalising ion suppression effects.

Quercetin metabolites downregulate cyclooxygenase-2 transcription in human lymphocytes ex vivo but not in vivo.

Flavonoids have the potential to modulate inflammation by inhibition of cyclooxygenase-2 (COX-2) transcription. In this study, we compared the effect of the human flavonoid plasma metabolites (quercetin 3'-sulfate, quercetin 3-glucuronide and 3'-methylquercetin 3-glucuronide) on expression of COX-2 mRNA in human lymphocytes ex vivo using TaqMan real-time RT-PCR. We show that the flavonoid quercetin metabolites as detected in human plasma at physiologically significant concentrations inhibit COX-2 expression in human lymphocytes ex vivo. To examine the effect in vivo, we measured COX-2 mRNA levels in 8 subjects (5 men and 3 women) participating in a 3-way, single-blind, randomized crossover study after consumption of a single meal of white, low-quercetin onions, compared with yellow, high-quercetin onions. After consumption of high-quercetin onions, quercetin conjugates were detected in plasma (up to a maximum concentration of 4 micro mol/L at approximately 1 h). However, the expression of COX-2 mRNA in lymphocytes was unchanged by the consumption of high-quercetin onions compared with the low-quercetin group. The results show that a single high dose of the flavonoid quercetin from onions does not change COX-2 mRNA expression in human lymphocytes in vivo even though this change occurred in vitro and ex vivo.