Robust paths to net greenhouse gas mitigation and negative emissions via advanced biofuels.

Biofuel and bioenergy systems are integral to most climate stabilization scenarios for displacement of transport sector fossil fuel use and for producing negative emissions via carbon capture and storage (CCS). However, the net greenhouse gas mitigation benefit of such pathways is controversial due to concerns around ecosystem carbon losses from land use change and foregone sequestration benefits from alternative land uses. Here, we couple bottom-up ecosystem simulation with models of cellulosic biofuel production and CCS in order to track ecosystem and supply chain carbon flows for current and future biofuel systems, with comparison to competing land-based biological mitigation schemes. Analyzing three contrasting US case study sites, we show that on land transitioning out of crops or pasture, switchgrass cultivation for cellulosic ethanol production has per-hectare mitigation potential comparable to reforestation and severalfold greater than grassland restoration. In contrast, harvesting and converting existing secondary forest at those sites incurs large initial carbon debt requiring long payback periods. We also highlight how plausible future improvements in energy crop yields and biorefining technology together with CCS would achieve mitigation potential 4 and 15 times greater than forest and grassland restoration, respectively. Finally, we show that recent estimates of induced land use change are small relative to the opportunities for improving system performance that we quantify here. While climate and other ecosystem service benefits cannot be taken for granted from cellulosic biofuel deployment, our scenarios illustrate how conventional and carbon-negative biofuel systems could make a near-term, robust, and distinctive contribution to the climate challenge.

Biomass fuel use and acute respiratory infection among children younger than 5 years in Ethiopia: a systematic review and meta-analysis.

OBJECTIVES: The objective of this study was to estimate the magnitude of acute respiratory infection (ARI) among children younger than 5 years (under-five children) and its association with biomass fuel use for domestic purposes and other behavioural and housing characteristics in Ethiopia. STUDY DESIGN: Systematic review and meta-analysis. METHODS: PubMed, Google Scholar, MEDLINE and the Cochrane Library were systematically searched (using the Preferred Items for Systematic Review and Meta-analysis guideline) for studies that reported an association between biomass fuel use for domestic purposes and ARI. Grey literature and other sources of unpublished information, which were subjected to the same extraction methods and quality appraisal as published studies, were also identified. A meta-analysis was performed to combine the quantitative measures from eligible individual studies into a summary estimate. Quality assessment was conducted using the modified Newcastle-Ottawa Scale quality assessment tool for cross-sectional and case-control studies. Funnel and Doi plots were used to detect potential publication bias. Statistical analyses were performed using Comprehensive Meta-Analysis and MetaXL, version 5.3, software. RESULTS: A total of 21 (18 cross-sectional and 3 case-control) eligible studies with their combined 30,013 participants were reviewed. The overall pooled prevalence of ARI among under-five children in households where biomass fuel was the main source of energy was estimated to be 22% (95% confidence interval [CI]: 17-29). In the subgroup analysis by area of residence, the highest prevalence was found in urban regions 26% (95% CI: 24-28). Based on the preceding 2 weeks before the interview, a significant association was found between biomass fuel use and ARI (odds ratio [OR] = 2.6, 95% CI: 2.05-3.30). In addition to biomass fuel use, being female (OR = 1.57, 95% CI: 1.06-2.33), absence of a window in the kitchen (OR = 2.89, 95% CI: 2.11-3.96), being carried on the back or in lap during cooking (OR = 2.76, 95% CI: 1.96-3.89) and non-separated kitchen from the main house (OR = 1.99, 95% CI: 1.49-2.68) were associated with ARI. CONCLUSIONS: Based on the results of this review, ARI among under-five children remains high. The present study also revealed that ARI is associated with biomass fuel use, child's gender, absence of a window in the kitchen, non-separated kitchen and carrying the child while cooking. Improved solid fuel stoves, advanced combustion designs, windows or chimneys, separating the kitchen from the main house are all measures required to reduce ARI in under-five children. SYSTEMATIC REVIEW REGISTRATION: The review has been registered with PROSPERO (registration number CRD42020181372).

Biocides Used as Additives to Biodiesels and Their Risks to the Environment and Public Health: A Review.

One of the advantages of using biodiesel and its blends with diesel oil is the lower levels of emissions of particulate matter, sulfur dioxide, carbon monoxide, among others, making it less harmful to the environment and to humans. However, this biofuel is susceptible to microbial contamination and biodeterioration. In this sense, studies on the use of effective low toxicity biocides are being carried out, and this work aims to present the latest information (2008⁻2018) available in the scientific databases, on the use of biocides in biodiesel, mainly concerning their toxicity to the environment and public health. The results showed that in relation to the control of microbial contamination, the current scenario is limited, with seven publications, in which the most studied additives were isothiazolinones, oxazolidines, thiocyanates, morpholines, oxaborinanes, thiocarbamates and phenolic antioxidants. Studies regarding direct experiments with humans have not been found, showing the need for more studies in this area, since the potential growth of biodiesel production and consumption in the world is evident. Thus, there are need for more studies on antimicrobial products for use in biodiesel, with good broad-spectrum activity (bactericidal and fungicidal), and further toxicological tests to ensure no or little impact on the environment.

Community Participatory Interventions to Improve Farmer Knowledge and Practices of Household Biogas Unit Operation in Ha Nam Province, Vietnam.

CONTEXT: The use of biogas systems to treat livestock waste is a common practice in Vietnam. However, farmers' knowledge and practices of the safe and appropriate use of household biogas units (HBUs) are still limited and could negatively impact human, animal, and environmental health. OBJECTIVE: To assess the effectiveness of an intervention to improve knowledge and practices of biogas operation among farmers in 2 communes of Ha Nam Province, Vietnam. DESIGN: A community-based intervention approach. SETTING: This study was conducted from 2015 to 2016 in 2 communes of Ha Nam Province, Vietnam. PARTICIPANTS: Only farmers with HBUs (N = 399) participated in this research. Farmers were assigned to either an intervention group or a control group at a ratio of 1:2. INTERVENTION: Two intervention steps were implemented over a 6-month period as follows: (i) the core farmer group trained in 6 steps of HBU safe handling practice; and (ii) the core farmer group conducted peer-to-peer communication with its neighbors in the commune using the provided material. MAIN OUTCOME MEASURE(S): Farmers' knowledge and practices in biogas operation were assessed by a structured questionnaire. The questionnaire was administered before (baseline) and after the intervention (follow-up) to both the control and intervention groups. RESULTS: There was a significant difference in the knowledge and practices of biogas operation between the 2 groups, in which farmers in the intervention group demonstrated better understanding of the related topic than the control group (P < .05, t test). A linear regression model indicated that baseline and follow-up scores in both knowledge and practices of the intervention group were higher than those of the control group. After the intervention, the mean difference score in knowledge and practices between the intervention and control groups was 5.0 and 2.0 points, respectively (P < .01). CONCLUSION: A community-based intervention approach could be applied to improve knowledge and practices among farmers in using biogas systems. However, further studies should be conducted to assess the sustainability and effectiveness of this model.

[Preliminary analysis of lung function of population with biofuel smoke exposure].

Objective: To analyse the impaired lung functions of people with biofuel smoke exposure. Methods: Nonsmokers with biofuel smoke exposure were selected as research objects in a mountainous area of northern Guangdong where the families used biofuels as main energies and the nonsmokers without biofuel smoke exposure in the same area as control. Questionnaire interviews and spirometry tests were performed on all subjects. To analyse the differences of lung functions in both. Results: Seventy hundred and seventeen subjects were enro1led in this study.There were 530 nonsmokers with biofuel smoke exposure(observation group) including 442 women and 88 men, average age 54±10. There were 187 nonsmokers without biofuel smoke exposure(control group) including 141 women and 46 men, average age 54±10. There was no significant difference between two groups in age, height, weight, BMI, waist circumference, hip circumference and waist/hip ratio(P>0.05). The pulmonary ventilation function index(FEV(1)%Pred, FEV(1)/FVC) in the observation group was significantly less than that in control group [(100±18) vs.(106±25); (80±10) vs.(83±6) respectively, P<0.05]. Small airway function index(PEF25, PEF50, PEF75, MMPEF and MMPEF%Pred) was significantly less than that in control group(P<0.01). According to the univariate regression analysis and multivariate regression analysis, regression coefficients between BIOFUEL-INDEX and FEV/FVC was -0.1, 95%CI(-0.1, -0.1, P<0.01). According to the threshold analysis, the vertice of BIOFUEL-INDEX was 46.0, where the predicted Y value was 81.76, 95%CI (80.2, 83.33). When BIOFUEL-INDEX<46.0, the regression coefficient was 0, 95%CI (-0.1, 0.0)(P>0.05); when BIOFUEL-INDEX> 46.0, the regression coefficient 2 was -0.1, 95%CI (-0.2, -0.1)(P<0.01). The difference between coefficient 2 and 1 was -0.1, 95%CI (-0.2, 0.0), which was statistically significant (P<0.05). The Log-Likelihood ratio between Model I and Model Ⅱ had statistical significance (P=0.019). Conclusions: The biofuel smokes exposure causes damages in lung function.

Health impacts of anthropogenic biomass burning in the developed world.

Climate change policies have stimulated a shift towards renewable energy sources such as biomass. The economic crisis of 2008 has also increased the practice of household biomass burning as it is often cheaper than using oil, gas or electricity for heating. As a result, household biomass combustion is becoming an important source of air pollutants in the European Union.This position paper discusses the contribution of biomass combustion to pollution levels in Europe, and the emerging evidence on the adverse health effects of biomass combustion products.Epidemiological studies in the developed world have documented associations between indoor and outdoor exposure to biomass combustion products and a range of adverse health effects. A conservative estimate of the current contribution of biomass smoke to premature mortality in Europe amounts to at least 40 000 deaths per year.We conclude that emissions from current biomass combustion products negatively affect respiratory and, possibly, cardiovascular health in Europe. Biomass combustion emissions, in contrast to emissions from most other sources of air pollution, are increasing. More needs to be done to further document the health effects of biomass combustion in Europe, and to reduce emissions of harmful biomass combustion products to protect public health.

Effectiveness of selective catalytic reduction systems on reducing gaseous emissions from an engine using diesel and biodiesel blends.

The aim of this investigation was to quantify organic and inorganic gas emissions from a four-cylinder diesel engine equipped with a urea selective catalytic reduction (SCR) system. Using a bench dynamometer, the emissions from the following mixtures were evaluated using a Fourier transform infrared (FTIR) spectrometer: low-sulfur diesel (LSD), ultralow-sulfur diesel (ULSD), and a blend of 20% soybean biodiesel and 80% ULSD (B20). For all studied fuels, the use of the SCR system yielded statistically significant (p < 0.05) lower NOx emissions. In the case of the LSD and ULSD fuels, the SCR system also significantly reduced emissions of compounds with high photochemical ozone creation potential, such as formaldehyde. However, for all tested fuels, the SCR system produced significantly (p < 0.05) higher emissions of N2O. In the case of LSD, the NH3 emissions were elevated, and in the case of ULSD and B20 fuels, the non-methane hydrocarbon (NMHC) and total hydrocarbon of diesel (HCD) emissions were significantly higher.

Carbon accounting and economic model uncertainty of emissions from biofuels-induced land use change.

Few of the numerous published studies of the emissions from biofuels-induced "indirect" land use change (ILUC) attempt to propagate and quantify uncertainty, and those that have done so have restricted their analysis to a portion of the modeling systems used. In this study, we pair a global, computable general equilibrium model with a model of greenhouse gas emissions from land-use change to quantify the parametric uncertainty in the paired modeling system's estimates of greenhouse gas emissions from ILUC induced by expanded production of three biofuels. We find that for the three fuel systems examined--US corn ethanol, Brazilian sugar cane ethanol, and US soybean biodiesel--95% of the results occurred within ±20 g CO2e MJ(-1) of the mean (coefficient of variation of 20-45%), with economic model parameters related to crop yield and the productivity of newly converted cropland (from forestry and pasture) contributing most of the variance in estimated ILUC emissions intensity. Although the experiments performed here allow us to characterize parametric uncertainty, changes to the model structure have the potential to shift the mean by tens of grams of CO2e per megajoule and further broaden distributions for ILUC emission intensities.

Biodiesel exhaust: the need for a systematic approach to health effects research.

Biodiesel is a generic term for fuel that can be made from virtually any plant or animal oil via transesterification of triglycerides with an alcohol (and usually a catalyst). Biodiesel has received considerable scientific attention in recent years, as it is a renewable resource that is directly able to replace mineral diesel in many engines. Additionally, some countries have mandated a minimum biodiesel content in all diesel fuel sold on environmental grounds. When combusted, biodiesel produces exhaust emissions containing particulate matter, adsorbed chemicals and a range of gases. In many cases, absolute amounts of these pollutants are lower in biodiesel exhaust compared with mineral diesel exhaust, leading to speculation that biodiesel exhaust may be less harmful to health. Additionally, engine performance studies show that the concentrations of these pollutants vary significantly depending on the renewable oil used to make the biodiesel and the ratio of biodiesel to mineral diesel in the fuel mix. Given the strategic and legislative push towards the use of biodiesel in many countries, a concerning possibility is that certain biodiesels may produce exhaust emissions that are more harmful to health than others. This variation suggests that a comprehensive, systematic and comparative approach to assessing the potential for a range of different biodiesel exhausts to affect health is urgently required. Such an assessment could inform biodiesel production priorities, drive research and development into new exhaust treatment technologies, and ultimately minimize the health impacts of biodiesel exhaust exposure.

Effect of indoor air pollution from biomass and solid fuel combustion on symptoms of preeclampsia/eclampsia in Indian women.

Available evidence concerning the association between indoor air pollution (IAP) from biomass and solid fuel combustion and preeclampsia/eclampsia is not available in developing countries. We investigated the association between exposure to IAP from biomass and solid fuel combustion and symptoms of preeclampsia/eclampsia in Indian women by analyzing cross-sectional data from India's third National Family Health Survey (NFHS-3, 2005-2006). Self-reported symptoms of preeclampsia/eclampsia during pregnancy such as convulsions (not from fever), swelling of legs, body or face, excessive fatigue or vision difficulty during daylight, were obtained from 39,657 women aged 15-49 years who had a live birth in the previous 5 years. Effects of exposure to cooking smoke, ascertained by type of fuel used for cooking on preeclampsia/eclampsia risk, were estimated using logistic regression after adjusting for various confounders. Results indicate that women living in households using biomass and solid fuels have two times higher likelihood of reporting preeclampsia/eclampsia symptoms than do those living in households using cleaner fuels (OR = 2.21; 95%: 1.26-3.87; P = 0.006), even after controlling for the effects of a number of potentially confounding factors. This study is the first to empirically estimate the associations of IAP from biomass and solid fuel combustion and reported symptoms suggestive of preeclampsia/eclampsia in a large nationally representative sample of Indian women and we observed increased risk. These findings have important program and policy implications for countries such as India, where large proportions of the population rely on polluting biomass fuels for cooking and space heating. More epidemiological research with detailed exposure assessments and clinical measures of preeclampsia/eclampsia is needed in a developing country setting to validate these findings.

Respiratory health effects of air pollution: update on biomass smoke and traffic pollution.

Mounting evidence suggests that air pollution contributes to the large global burden of respiratory and allergic diseases, including asthma, chronic obstructive pulmonary disease, pneumonia, and possibly tuberculosis. Although associations between air pollution and respiratory disease are complex, recent epidemiologic studies have led to an increased recognition of the emerging importance of traffic-related air pollution in both developed and less-developed countries, as well as the continued importance of emissions from domestic fires burning biomass fuels, primarily in the less-developed world. Emissions from these sources lead to personal exposures to complex mixtures of air pollutants that change rapidly in space and time because of varying emission rates, distances from source, ventilation rates, and other factors. Although the high degree of variability in personal exposure to pollutants from these sources remains a challenge, newer methods for measuring and modeling these exposures are beginning to unravel complex associations with asthma and other respiratory tract diseases. These studies indicate that air pollution from these sources is a major preventable cause of increased incidence and exacerbation of respiratory disease. Physicians can help to reduce the risk of adverse respiratory effects of exposure to biomass and traffic air pollutants by promoting awareness and supporting individual and community-level interventions.

Peak expiratory flow rates among women exposed to different cooking fuels in rural India.

Plant or animal based material burned for cooking or heating (biofuels) can cause indoor air pollution. We studied the effect of exposure to biofuel and other types of fuel smoke on peak expiratory flow rates (PEFR) among rural Indian women. We conducted a community based cross-sectional study of 760 non-smoking women who cooked using one of four types of fuel: biofuel, kerosene, liquefied petroleum gas (LPG) or a combination of two or more fuels. A PEFR <80% of predicted was considered abnormal. An abnormal PEFR was seen in 43.3% of women using biofuels, 20.5% of those using kerosene, 23.4% of those using LPG and 21.4% of those using mixed fuel. Multivariate logistic regression analysis showed among those using mixed fuel, age [OR: - 2.08, 95% confidence interval (CI): 1.32 - 3.28, p = 0.00], height (OR: -1.06, 95% CI: 1.00 - 1.12, p = 0.02) and exposure index (estimated hours spent cooking daily multiplied by the years cooked) (OR: -2.74, 95% CI: 1.68 - 4.47, p = 0.00) were significant predictors of abnormal PEFR. Among women using biofuels and LPG, only exposure index was found to be a significant predictor of abnormal PEFR (p<0.05). No significant association was found between abnormal PEFR and exposure index among women who used only kerosene for fuel (p>0.05). Using mixed fuel was found to be more likely to cause an abnormal PEFR.

Biomass use and its health effects among the vulnerable and marginalized refugee families in the Gaza Strip.

Introduction: Biomass fuel remains the most common type of fuel used in many developing countries, leading to indoor air pollution and serious health impacts. Objective: The objective of this study was to compile evidence on the impact household fuel combustion has on child and adult health, with an emphasis on solid fuel use in Gaza. Methods: In this cross-sectional study, 110 structured self-administered questionnaires were distributed in April 2019 among families living in the Al-Maghazi refugee camp. Results: Participants reported that the main fuel used were wood, coal, cardboard, and a mix of wood, cardboard, and plastic, which were used for cooking, heating, baking, boiling water, and lighting. The most common symptoms were nasal irritation (71.8%), followed by headache (66.4%) and dizziness (65.4%). The results of logistic regression showed that the participants who used wood fuel had a higher chance of feeling eye irritation than those who used a mix of wood, cardboard, and dried grass (OR = 1.316; 95% CI = 1.54-8.99). The participants who opened windows during the burning process of biomass fuel were five times more likely to develop pneumonia than those who closed windows (OR = 5.53; 95%CI = 11.60-19.0). Conclusion: there is an urgent need for community awareness campaigns designed to inform people about the risks of exposure to biomass fuel smoke and how to better implement household ventilation.

Association of cooking fuel use with risk of cancer and all-cause mortality among Chinese elderly people: a prospective cohort study.

When cooking with biomass and fossil fuels, their incomplete burning can lead to air pollution, which can trigger pernicious effects on people's health, especially among the elderly, who are more vulnerable to toxic and harmful environmental damage. This study explored the association between different cooking fuel types and the risk of cancer and all-cause mortality among seniors constructing Cox regression models. Data were obtained by linking waves of 6, 7, and 8 of the Chinese Longitudinal Healthy Longevity Survey, which included a total of 7269 participants who were 65 years old and over. Cooking fuels were categorized as either biomass, fossil, or clean fuels. And the effects of switching cooking fuels on death risk were also investigated using Cox regression models. The results indicate that, compared with the users of clean fuels, individuals using biomass or fossil fuels were at a greater death risk for cancer [HR (95% CI): biomass, 1.13 (1.05-1.20); fossil, 1.16 (1.06-1.25)] and all causes [HR (95% CI): biomass, 1.29 (1.16-1.42); fossil, 1.32 (1.22-1.50)]. Furthermore, compared with sustained users of biomass fuels, individuals converting from biomass to clean fuels significantly reduced death risk for cancer [HR (95% CI): 0.81 (0.72-0.95)] and all causes [HR (95% CI): 0.76 (0.64-0.93)]. Similarly, all-cause death risk [HR (95% CI): 0.77 (0.62-0.93)] was noticeably reduced among these participants converting from fossil to clean fuels than persistent users of fossil fuels. Subgroup analyses revealed that males had a greater cancer and all-cause death risk when exposed to unclean fuels. These findings can inform the development of policies and the implementation of measures related to cooking fuel use to promote the health of older people and reduce the burden of disease on society.

Risk assessment of PM(2.5) to child residents in Brazilian Amazon region with biofuel production.

BACKGROUND: Exposure to fine fractions of particulate matter (PM(2.5)) is associated with increased hospital admissions and mortality for respiratory and cardiovascular disease in children and the elderly. This study aims to estimate the toxicological risk of PM(2.5) from biomass burning in children and adolescents between the age of 6 and 14 in Tangará da Serra, a municipality of Subequatorial Brazilian Amazon. METHODS: Risk assessment methodology was applied to estimate the risk quotient in two scenarios of exposure according to local seasonality. The potential dose of PM(2.5) was estimated using the Monte Carlo simulation, stratifying the population by age, gender, asthma and Body Mass Index (BMI). RESULTS: Male asthmatic children under the age of 8 at normal body rate had the highest risk quotient among the subgroups. The general potential average dose of PM(2.5) was 1.95 µg/kg.day (95% CI: 1.62 - 2.27) during the dry scenario and 0.32 µg/kg.day (95% CI: 0.29 - 0.34) in the rainy scenario. During the dry season, children and adolescents showed a toxicological risk to PM(2.5) of 2.07 µg/kg.day (95% CI: 1.85 - 2 .30). CONCLUSIONS: Children and adolescents living in the Subequatorial Brazilian Amazon region were exposed to high levels of PM(2.5) resulting in toxicological risk for this multi-pollutant. The toxicological risk quotients of children in this region were comparable or higher to children living in metropolitan regions with PM(2.5) air pollution above the recommended limits to human health.

Respiratory disease associated with solid biomass fuel exposure in rural women and children: systematic review and meta-analysis.

BACKGROUND: Numerous studies with varying associations between domestic use of solid biomass fuels (wood, dung, crop residue, charcoal) and respiratory diseases have been reported. OBJECTIVE: To present the current data systematically associating use of biomass fuels with respiratory outcomes in rural women and children. METHODS: Systematic searches were conducted in 13 electronic databases. Data were abstracted from original articles that satisfied selection criteria for meta-analyses. Publication bias and heterogeneity of samples were tested. Studies with common diagnoses were analysed using random-effect models. RESULTS: A total of 2717 studies were identified. Fifty-one studies were selected for data extraction and 25 studies were suitable for meta-analysis. The overall pooled ORs indicate significant associations with acute respiratory infection in children (OR 3.53, 95% CI 1.94 to 6.43), chronic bronchitis in women (OR 2.52, 95% CI 1.88 to 3.38) and chronic obstructive pulmonary disease in women (OR 2.40, 95% CI 1.47 to 3.93). In contrast, no significant association with asthma in children or women was noted. CONCLUSION: Biomass fuel exposure is associated with diverse respiratory diseases in rural populations. Concerted efforts in improving stove design and lowering exposure to smoke emission may reduce respiratory disease associated with biomass fuel exposure.

Association between biofuel exposure and adverse birth outcomes at high altitudes in Peru: a matched case-control study.

Nearly one-third of the Peruvian population burns biofuels for cooking. Similarly, approximately one-third of this population lives at high altitudes. Cooking with biofuels and living at high altitudes have been implicated in adverse perinatal outcomes. This study attempted to determine the risk of low birth weight (LBW) and/or preterm delivery in relation to biofuel use in inhabitants at high altitudes in Peru. A matched-case study was performed in two high-altitude cities. All subjects (n=190) were identified from public-hospital records. Cases were matched by hospital by week of birth and area of residence. Cases were defined as: women with an at-term but LBW newborn; or women with a preterm birth. Adjusted conditional logistic regression analyses were used to determine odds ratio. Fifty-two percent of the cases used biofuel whereas only 30% of the controls used biofuel. The use of biofuel for cooking was found to be strongly associated with increased risks of LBW, but was not significantly linked to preterm births.