Factors Determining Black Carbon Exposures among Pregnant Women Enrolled in the HAPIN Trial.

Residential biomass burning is an important source of black carbon (BC) exposure among rural communities in low- and middle-income countries. We collected 7165 personal BC samples and individual/household level information from 3103 pregnant women enrolled in the Household Air Pollution Intervention Network trial. Women in the intervention arm received free liquefied petroleum gas stoves and fuel throughout pregnancy; women in the control arm continued the use of biomass stoves. Median (IQR) postintervention BC exposures were 9.6 µg/m3 (5.2-14.0) for controls and 2.8 µg/m3 (1.6-4.8) for the intervention group. Using mixed models, we characterized predictors of BC exposure and assessed how exposure contrasts differed between arms by select predictors. Primary stove type was the strongest predictor (R2 = 0.42); the models including kerosene use, kitchen location, education, occupation, or stove use hours also provided additional explanatory power from the base model adjusted only for the study site. Our full, trial-wide, model explained 48% of the variation in BC exposures. We found evidence that the BC exposure contrast between arms differed by study site, adherence to the assigned study stove, and whether the participant cooked. Our findings highlight factors that may be addressed before and during studies to implement more impactful cookstove intervention trials.

Using fuzzy cognitive map in bow tie method for dynamic risk assessment of spherical storage tanks: A case study.

The present study aimed to perform a dynamic risk assessment of liquefied petroleum gas (LPG) in spherical storage tanks using the Hazard and Operability (HAZOP) method. The "LPG release from spherical storage tank" scenario was determined to be a top event based on the risk level. The causes and consequences of this scenario were then specified using the Bow-Tie method. Additionally, fuzzy cognitive mapping (FCM) was utilized to identify the most critical threats, consequences, and effective barriers in a dynamic approach. Results showed that fracture/rupture in pipelines/a storage tank due to fire had the highest output degree and was identified as the most influential threat in the occurrence of the LPG release. Fatality/injury due to fire and explosion had the highest input degree and was more influenced by the release of LPG as the main consequence in the selected scenario. The findings of this study enabled us to make a logical decision about effective barriers for avoiding and minimizing the release of LPG and its threats and consequences based on the fuzzy cognitive map. Moreover, the results of this study showed that the FCM method could determine the most critical nodes with a higher degree and represent their relationships.

Household cooking fuel and gallbladder cancer risk: a multi-centre case-control study in India.

PURPOSE: Gallbladder cancers (GBC), unique to certain geographical regions, are lethal digestive tract cancers, disproportionately affecting women, with limited information on risk factors. METHODS: We evaluated the association between household cooking fuel and GBC risk in a hospital-based case-control study conducted in the North-East and East Indian states of Assam and Bihar. We explored the potential mediation by diet, fire-vents, 'daily exposure duration' and parity (among women). We recruited biopsy-confirmed GBC (n = 214) men and women aged 30-69 years between 2019 and 2021, and controls frequency-matched by age, sex and region (n = 166). Information about cooking fuel, lifestyle, personal and family history, female reproductive factors, socio-demographics, and anthropometrics was collected. We tested associations using multivariable logistic regression analyses. RESULTS: All participants (73.4% women) were categorised based on predominant cooking fuel use. Group-1: LPG (Liquefied Petroleum Gas) users in the previous 20 years and above without concurrent biomass use (26.15%); Group-2: LPG users in the previous 20 years and above with concurrent secondary biomass use (15.9%); Group-3: Biomass users for ≥ 20 years (57.95%). Compared to group-1, accounting for confounders, GBC risk was higher in group-2 [OR: 2.02; 95% CI: 1.00-4.07] and group-3 [OR: 2.01; 95% CI: 1.08-3.73] (p-trend:0.020). These associations strengthened among women that attenuated with high daily consumption of fruits-vegetables but not with fire-vents, 'daily exposure duration' or parity. CONCLUSION: Biomass burning was associated with a high-risk for GBC and should be considered as a modifiable risk factor for GBC. Clean cooking fuel can potentially mitigate, and a healthy diet can partially reduce the risk among women.

Testing the effectiveness of household fuel conservation strategies: Policy implications for increasing the affordability of exclusive clean cooking.

BACKGROUND: Exclusive clean fuel use is essential for realizing health and other benefits but is often unaffordable. Decreasing household-level fuel needs could make exclusive clean fuel use more affordable, but there is a lack of knowledge on the amount of fuel savings that could be achieved through fuel conservation behaviors relevant to rural settings in low- and middle-income countries. METHODS: Within a trial in Peru, we trained a random half of intervention participants, who had previously received a liquefied petroleum gas (LPG) stove and were purchasing their own fuel, on fuel conservation strategies. We measured the amount of fuel and mega joules (MJ) of energy consumed by all participants, including control participants who were receiving free fuel from the trial. We administered surveys on fuel conservation behaviors and assigned a score based on the number of behaviors performed. RESULTS: Intervention participants with the training had a slightly higher conservation score than those without (7.2 vs. 6.6 points; p = 0.07). Across all participants, average daily energy consumption decreased by 9.5 MJ for each 1-point increase in conservation score (p < 0.001). Among households who used exclusively LPG (n = 99), each 1-point increase in conservation score was associated with a 0.04 kg decrease in LPG consumption per household per day (p = 0.03). Using pressure cookers and heating water in the sun decreased energy use, while using clay pots and forgetting to close stove knobs increased energy use. CONCLUSION: Our findings suggest that a household could save 1.16 kg of LPG per month for each additional fuel conservation behavior, for a maximum potential savings of 8.1 kg per month. Fuel conservation messaging could be integrated into national household energy policies to increase the affordability of exclusive clean fuel use, and subsequently achieve the environmental and health benefits that could accompany such a transition.

Did COVID-19 Change the Availability and Use of Clean Energy for Cooking? Evidence From Ghana.

A major part of Ghana's current household energy policy is focused on using a branded cylinder recirculation model (BCRM) to promote the safe use of Liquefied Petroleum Gas (LPG) for primary cooking. The implementation of the BCRM is expected to increase LPG adoption by households to the announced policy goal of 50% of the population by 2030. We investigated the impact of the COVID-19 pandemic on the implementation of the BCRM, availability, and household use of cleaner fuels. This was assessed using existing data on clean fuel use prior to the COVID-19 pandemic. Additional data was collected using questionnaire-based household surveys and qualitative interviews. It was found that the expansion of BCRM was significantly impacted by the COVID-19 pandemic. Planning activities such as baseline data collection and stakeholder engagement were delayed due to the COVID-19 restrictions. Changes in household incomes during the pandemic had the biggest percentage effect on household choice of cooking fuel, causing a regression in some cases, to polluting fuel use. This study provides insights that could be valuable in future understanding of the interactions between pandemic control measures and economic disruptions that may affect household energy choices for cooking.

Fidelity and adherence to a liquefied petroleum gas stove and fuel intervention: The multi-country Household Air Pollution Intervention Network (HAPIN) trial.

BACKGROUND: Reducing household air pollution (HAP) to levels associated with health benefits requires nearly exclusive use of clean cooking fuels and abandonment of traditional biomass fuels. METHODS: The Household Air Pollution Intervention Network (HAPIN) trial randomized 3,195 pregnant women in Guatemala, India, Peru, and Rwanda to receive a liquefied petroleum gas (LPG) stove intervention (n = 1,590), with controls expected to continue cooking with biomass fuels (n = 1,605). We assessed fidelity to intervention implementation and participant adherence to the intervention starting in pregnancy through the infant's first birthday using fuel delivery and repair records, surveys, observations, and temperature-logging stove use monitors (SUMs). RESULTS: Fidelity and adherence to the HAPIN intervention were high. Median time required to refill LPG cylinders was 1 day (interquartile range 0-2). Although 26% (n = 410) of intervention participants reported running out of LPG at some point, the number of times was low (median: 1 day [Q1, Q3: 1, 2]) and mostly limited to the first four months of the COVID-19 pandemic. Most repairs were completed on the same day as problems were reported. Traditional stove use was observed in only 3% of observation visits, and 89% of these observations were followed up with behavioral reinforcement. According to SUMs data, intervention households used their traditional stove a median of 0.4% of all monitored days, and 81% used the traditional stove < 1 day per month. Traditional stove use was slightly higher post-COVID-19 (detected on a median [Q1, Q3] of 0.0% [0.0%, 3.4%] of days) than pre-COVID-19 (0.0% [0.0%, 1.6%] of days). There was no significant difference in intervention adherence pre- and post-birth. CONCLUSION: Free stoves and an unlimited supply of LPG fuel delivered to participating homes combined with timely repairs, behavioral messaging, and comprehensive stove use monitoring contributed to high intervention fidelity and near-exclusive LPG use within the HAPIN trial.

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

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

Fidelity and adherence to a liquefied petroleum gas stove and fuel intervention: the multi-country Household Air Pollution Intervention Network (HAPIN) trial.

Background: Reducing household air pollution (HAP) to levels associated with health benefits requires nearly exclusive use of clean cooking fuels and abandonment of traditional biomass fuels. Methods: The Household Air Pollution Intervention Network (HAPIN) trial randomized 3,195 pregnant women in Guatemala, India, Peru, and Rwanda to receive a liquefied petroleum gas (LPG) stove intervention (n=1,590), with controls expected to continue cooking with biomass fuels (n=1,605). We assessed fidelity to intervention implementation and participant adherence to the intervention starting in pregnancy through the infant's first birthday using fuel delivery and repair records, surveys, observations, and temperature-logging stove use monitors (SUMs). Results: Fidelity and adherence to the HAPIN intervention were high. Median time required to refill LPG cylinders was 1 day (interquartile range 0-2). Although 26% (n=410) of intervention participants reported running out of LPG at some point, the number of times was low (median: 1 day [Q1, Q3: 1, 2]) and mostly limited to the first four months of the COVID-19 pandemic. Most repairs were completed on the same day as problems were reported. Traditional stove use was observed in only 3% of observation visits, and 89% of these observations were followed up with behavioral reinforcement. According to SUMs data, intervention households used their traditional stove a median of 0.4% of all monitored days, and 81% used the traditional stove <1 day per month. Traditional stove use was slightly higher post-COVID-19 (detected on a median [Q1, Q3] of 0.0% [0.0%, 3.4%] of days) than pre-COVID-19 (0.0% [0.0%, 1.6%] of days). There was no significant difference in intervention adherence pre- and post-birth. Conclusion: Free stoves and an unlimited supply of LPG fuel delivered to participating homes combined with timely repairs, behavioral messaging, and comprehensive stove use monitoring contributed to high intervention fidelity and near-exclusive LPG use within the HAPIN trial.

A holistic review on the recent trends, advances, and challenges for high-precision room temperature liquefied petroleum gas sensors.

Liquefied petroleum gas (LPG), which is mainly composed of hydrocarbons, such as propane and butane, is a flammable gas that is considered a clean source of energy. Currently, the overwhelming use of LPG as fuel in vehicles, domestic settings, and industry has led to several incidents and deaths globally due to leakage. As a result, the appropriate detection of LPG is vital; thus, gas-sensing devices that can monitor this gas rapidly and accurately at room temperature, are required. This work reviews the current advances in LPG gas sensors, which operate at room temperature. The influences of the synthesis methods and parameters, doping, and use of catalysts on the sensing performance are discussed. The formation of heterostructures made from semiconducting metal oxides, polymers, and graphene-based materials, which enhance the sensor selectivity and sensitivity, is also discussed. The future trends and challenges confronted in the advancement of LPG room temperature operational gas sensors, and critical ideas concerning the future evolution of LPG gas sensors, are deliberated. Additionally, the advancements in the next-generation gas sensors, such as the wireless detection of LPG leakage, self-powered sensors driven by triboelectric/piezoelectric mechanisms, and artificial intelligent systems are also reviewed. This review further focuses on the use of smartphones to circumvent the use of costly instruments and paves the way for cost-efficient and portable monitoring of LPG. Finally, the approach of utilizing the Internet of Things (IoT) to detect/monitor the leakage of LPG has also been discussed, which will provide better alerts to the users and thus minimize the effects of leakages.

Sustained use of liquefied petroleum gas following one year of free fuel and behavioral support in Puno, Peru.

Background: Existing efforts to promote cleaner fuels have not achieved exclusive use. We investigated whether receiving 12 months of free liquefied petroleum gas (LPG) and behavioral support could motivate continued purchase and use. Methods: The Cardiopulmonary outcomes and Household Air Pollution (CHAP) trial enrolled 180 women. Half were randomly assigned to an intervention group, which included free LPG delivered in months 1-12 followed by a post-intervention period in which they no longer received free fuel (months 13-24). For the purposes of comparison, we also include months 1-12 of data from control participants. We tracked stove use with temperature monitors, surveys, and observations, and conducted in-depth interviews with 19 participants from the intervention group at the end of their post-intervention period. Results: Participants from the intervention group used their LPG stove for 85.4 % of monitored days and 63.2 % of cooking minutes during the post-intervention months (13-24) when they were not receiving free fuel from the trial. They used a traditional stove (fogón) on 45.1 % of days post-intervention, which is significantly lower than fogón use by control participants during the intervention period (72.2 % of days). In months 13-24 post-intervention, participants from the intervention group purchased on average 12.3 kg and spent 34.1 soles (10.3 USD) per month on LPG. Continued LPG use was higher among participants who said they could afford two tanks of LPG per month, did not cook for animals, and removed their traditional stove. Women described that becoming accustomed to LPG, support and training from the project, consistent LPG supply, choice between LPG providers, and access to delivery services facilitated sustained LPG use. However, high cost was a major barrier to exclusive use. Conclusion: A 12-month period of intensive LPG support achieved a high level of sustained LPG use post-intervention, but other strategies are needed to sustain exclusive use.

Effects of a household air pollution intervention using liquefied petroleum gas stoves, continuous fuel distribution and behavioural messaging on dietary and sodium intake of adult women in Puno, Peru: a randomised controlled trial.

OBJECTIVE: Household air pollution (HAP) is a widespread environmental exposure worldwide. While several cleaner fuel interventions have been implemented to reduce personal exposures to HAP, it is unclear if cooking with cleaner fuels also affects the choice of meals and dietary intake. DESIGN: Individually randomised, open-label controlled trial of a HAP intervention. We aimed to determine the effect of a HAP intervention on dietary and Na intake. Intervention participants received a liquefied petroleum gas (LPG) stove, continuous fuel delivery and behavioural messaging during 1 year whereas control participants continued with usual cooking practices that involved the use of biomass-burning stoves. Dietary outcomes included energy, energy-adjusted macronutrients and Na intake at baseline, 6 months and 12 months post-randomisation using 24-h dietary recalls and 24-h urine. We used t-tests to estimate differences between arms in the post-randomisation period. SETTING: Rural settings in Puno, Peru. PARTICIPANTS: One hundred women aged 25-64 years. RESULTS: At baseline, control and intervention participants were similar in age (47·4 v. 49·5 years) and had similar daily energy (8894·3 kJ v. 8295·5 kJ), carbohydrate (370·8 g v. 373·3 g) and Na intake (4·9 g v. 4·8 g). One year after randomisation, we did not find differences in average energy intake (9292·4 kJ v. 8788·3 kJ; P = 0·22) or Na intake (4·5 g v. 4·6 g; P = 0·79) between control and intervention participants. CONCLUSIONS: Our HAP intervention consisting of an LPG stove, continuous fuel distribution and behavioural messaging did not affect dietary and Na intake in rural Peru.

Activity and stability of lipase from Candida Antarctica after treatment in pressurized fluids.

Lipase B from Candida antarctica (CalB) is one of the biocatalysts most used in organic synthesis due to its ability to act in several medium, wide substrate specificity and enantioselectivity, tolerance to non-aqueous environment, and resistance to thermal deactivation. Thus, the objective of this work was to treat CalB in supercritical carbon dioxide (SC-CO2) and liquefied petroleum gas (LPG), and measure its activity before and after high-pressure treatment. Residual specific hydrolytic activities of 132% and 142% were observed when CalB was exposed to SC-CO2 at 35 â„ƒ, 75 bar and 1 h and to LPG at 65 â„ƒ, 30 bar and 1 h, respectively. Residual activity of the enzyme treated at high pressure was still above 100% until the 20th day of storage at low temperatures. There was no difference on the residual activity loss of CalB treated with LPG and stored at different temperatures over time. Greater difference was observed between CalB treated with CO2 and flash-frozen in liquid nitrogen (- 196 â„ƒ) followed by storage in freezer (- 10 â„ƒ) and CalB stored in freezer at - 10 â„ƒ. Such findings encourage deeper studies on CalB as well as other enzymes behavior under different types of pressurized fluids aiming at industrial application.

Impact of smokeless cooking fuel use on health status of women in a rural setting of eastern India.

The sustainable development goals (SDG 7.1) reinforce to ensure that everyone has access to affordable, safe and renewable energy. In India, women are typically responsible for cooking and are most vulnerable to household air contaminants. We conducted a descriptive cross-sectional comparative study in Odisha, India between exclusive LPG (liquefied petroleum gas) users and non-LPG users. A total of 900 women, 450 from each group, were randomly selected. The LPG-users had a better predictor of physical, psychological, social, and environmental wellbeing than non-LPG users. We found the ophthalmic disorders (adjusted odds ratio (AOR) 2.87, 95% CI 1.16-7.10, p = .023), asthma (AOR 2.05, 95% CI 1.15-3.65, p = .015), and ALRI (acute lower respiratory infections) (AOR 9.19, 95% CI 2.06-40.96, p < .004) were significantly higher in non-LPG users in comparison to LPG users. Access to smokeless cooking fuel will improve women's quality of life by eliminating the consumption of biofuel and thereby providing a healthier cooking environment.

Epidemiology and Early Bacteriology of Extremely Severe Burns from an LPG Tanker Explosion in Eastern China.

The incidence of liquefied petroleum gas (LPG)-related accidents in China has increased over the recent years. In addition, infection remains a big challenge in cases of severe burns. Therefore, the present study aimed to provide valuable information for a better control of infections in the event of such disasters. In this study, a total of 16 patients who suffered extremely severe burns after an LPG tanker explosion were included. Thereafter, bacteriological culture results were collected within a week. Of 16 patients, 13 (81.25%) were male and the average age of all patients was 60.63 years. In addition, the mean burned area was 83.03% TBSA. Additionally, a total of 553 organism cultures were conducted out of which 287 isolates (51.90%) showed positive results. Notably, 38.52% were Gram-negative bacteria, 7.59% were Gram-positive bacteria and 5.79% were fungi. Moreover, the most prevalent Gram-negative bacteria were Stenotrophomonas maltophilia (28.97%) followed by Acinetobacter baumannii (28.53%), and Klebsiella pneumoniae (14.02%). On the other hand, the three most predominant Gram-positive bacteria were Enterococcus faecalis (33.33%), Staphylococcus aureus (28.89%) and Staphylococcus sciuri (17.78%). Furthermore, the most common fungi included Candida (38.24%), Fusarium (20.59%) and Aspergillus fumigatus (14.71%). With regard to the bacterial resistance patterns, carbapenem-resistant organisms included Acinetobacter baumannii (97.80%), Pseudomonas aeruginosa (67.57%), and Klebsiella pneumoniae (75.56%). In addition, Staphylococcus sciuri, Staphylococcus epidermidis, and Staphylococcus haemolyticus were identified to be methicillin-resistant. This study revealed that there was a high incidence of infection in victims of severe burns as a result of mass burn accidents, accompanied by early fungal infection.

The role of liquefied petroleum gas in decarbonizing India: fresh evidence from wavelet-partial wavelet coherence approach.

India is predominantly a fossil fuel-intensive South Asian country that has traditionally settled for higher economic gains at the expense of lower environmental quality. However, in the contemporary era, it has become essential for India to come up with viable solutions that can enable the nation to transform its economy into a low-carbon one. Although replacing fossil fuel use with renewable energy sources is assumed to be the ideal pathway to decarbonizing the Indian economy, achieving this clean energy transition involves a long-term process. Thus, the Indian government should rather consider adoption of interim solutions to the environmental pollution problems faced by the nation. Against this backdrop, this study looks at whether enhancing the consumption level of liquefied petroleum gas, a relatively cleaner fossil fuel, can help India reduce its carbon dioxide emissions figures and attain environmentally sustainable economic growth. The econometric analysis is designed as per the theoretical framework of the environmental Kuznets curve hypothesis whereby the effects of economic growth on carbon dioxide emissions are examined controlling for liquefied petroleum gas consumption in the context of India between 1990 and 2018. Based on the findings from the autoregressive distributed lag model bounds test analysis, it is witnessed that there are long-run cointegrating relationships among per capita levels of carbon dioxide emissions, real gross domestic product, and liquefied petroleum gas consumption of India. Besides, the environmental Kuznets curve hypothesis is found to be valid only in the short run; however, it does not sustain in the long run since the economic growth-carbon dioxide emissions nexus is observed to follow a U-shaped relationship in the long run. Moreover, higher liquefied petroleum gas consumption is found to boost carbon dioxide emissions in the short run while reducing it in the long run. Furthermore, the findings from the wavelet and partial wavelet coherence and causality analyses also advocate in favor of promoting the use of liquefied petroleum gas in India in order to significantly curb the energy use-related carbon dioxide emission figures of the nation. Hence, considering these important findings, this study recommends that the Indian government should design policies for augmenting liquefied petroleum gas into the national energy mix and also adopt relevant green economic growth strategies in order to facilitate environmentally-sustainable growth of its economy.

Modifying influence of polyphenols on hematotoxicity, cardiotoxicity, and hepatotoxicity induced by liquefied petroleum gas in rats.

OBJECTIVE: This study was designed to investigate the effects of liquefied petroleum gas (LPG) on hematotoxic, cardiotoxic, and hepatotoxic indices and the modifying influence of selected polyphenols. METHODS: Adult male Wistar rats were exposed to1000 ppm LPG for 10 min at 12-h interval for 30 days with or without cotreatment with 50 mg/kg rutin, quercetin, tannic acid, or gallic acid followed by hematological, biochemical, and histopathological evaluations in animal tissues. RESULTS: Exposure to LPG induced hematotoxicity, cardiotoxicity, and hepatotoxicity. This is reflected in alterations to levels or activities of blood parameters (hemoglobin, packed cell volume, red blood cells, mean corpuscular volume, mean corpuscular hemoglobin, and platelets), enzymatic and nonenzymatic oxidative stress markers, nitrite, lactate dehydrogenase, creatine kinase-MB, transaminases, γ-glutamyl transpeptidase, bilirubin, and plasma albumin. LPG exposure also caused dyslipidemia and histoarchitectural changes. Treatment with the selected polyphenols effectively attenuated LPG-induced toxicity in rat tissues. CONCLUSION: The results indicate that continuous exposure to LPG could lead to blood-, heart-, and liver-related diseases and dietary polyphenols could provide benefits in diseases associated with LPG inhalation toxicity.

Scheduling the periodic delivery of liquefied petroleum gas tank with time window by using artificial intelligence approaches: An example in Taiwan.

INTRODUCTION: In Taiwan, liquefied petroleum gas tank users have to call a gas company to deliver a full liquefied petroleum gas tank when their tank is out of gas. The calls usually congest in the cooking time and the customers have to wait for a long time for a full liquefied petroleum gas tank. Additionally, allocating manpower is difficult for the gas company. OBJECTIVES: A strategy of periodic delivery for gas companies was presented to deliver liquefied petroleum gas tanks in advance and charge the gas fee based on the weight of returned tanks. Additionally, a new encoding scheme was proposed and embedded into three evolutionary algorithms to solve the nondeterministic polynomial-hard problem. The objective of the problem is to minimize the total traveling distance of the vehicle such that the delivery efficiency of tanks increases and the waiting time of customer decreases. METHODS: A new encoding scheme was presented to convert any random sequence of integers into a solution of the problem and embedded into three evolutionary algorithms, namely, immune algorithm, genetic algorithm, and particle swarm optimization, to solve the delivery problem. Additionally, the encoding scheme can be used to different frequency types of demand based on customers' requests. RESULTS: Numerical results, including a practical example in Yunlin, Taiwan, were provided to show that the adopted approaches can significantly improve the efficiency of delivery. CONCLUSIONS: The periodic delivery strategy and the new encoding scheme can effectively solve the practical problem of liquefied petroleum gas tank in Taiwan.

Analytical data on respiratory symptoms and pulmonary impairments due to exposure to non-combusted liquefied petroleum gas.

The article is aimed at assessing the effects of chronic exposure to non-combusted LPG on the prevalence of respiratory symptoms and appraising the potential pulmonary impairments among LPG vendors. A case control design in which vendors and non-vendors of LPG from Calabar, Nigeria were used for the data collection. Seventy five (75) apparently healthy LPG vendors and Seventy five (75) apparently healthy non LPG vendors, aged 18 to 50 years were considered. A structured questionnaire was randomly administered to the participants to obtain information on age, family history, medical history, physical lifestyle, drug usage, occupation and duration on the job. The Forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC) and peak expiratory flow (PEF) were obtained using a Spirometer while FEV1/FVC was calculated. Independent t-test was applied to determine the mean difference between the exposed and control groups at 5% level of significance. Chi-square test/Fisher's exact test was used to investigate all forms of associations in the study. It is evident in the data that nasal irritation/sneezing and cough were significantly associated with the LPG vendors. The pulmonary function parameters except FEV1/FVC indicated significant reduction among LPG vendors. The data can further be reused by applying regression analysis, correlation analysis to determine the relationship between pulmonary function indices and duration of exposure. Also, analysis of variance (ANOVA) can be used for determining the effect of interaction between age of exposed group and duration of exposure on pulmonary function parameters.

COVID-19 impacts on household energy & food security in a Kenyan informal settlement: The need for integrated approaches to the SDGs.

This longitudinal study presents the joint effects of a COVID-19 community lockdown on household energy and food security in an informal settlement in Nairobi, Kenya. Randomly administered surveys were completed from December 2019-March 2020 before community lockdown (n = 474) and repeated in April 2020 during lockdown (n = 194). Nearly universal (95%) income decline occurred during the lockdown and led to 88% of households reporting food insecurity. During lockdown, a quarter of households (n = 17) using liquefied petroleum gas (LPG), a cleaner cooking fuel typically available in pre-set quantities (e.g. 6 kg cylinders), switched to polluting cooking fuels (kerosene, wood), which could be purchased in smaller amounts or gathered for free. Household size increases during lockdown also led to participants' altering their cooking fuel, and changing their cooking behaviors and foods consumed. Further, households more likely to switch away from LPG had lower consumption prior to lockdown and had suffered greater income loss, compared with households that continued to use LPG. Thus, inequities in clean cooking fuel access may have been exacerbated by COVID-19 lockdown. These findings demonstrate the complex relationship between household demographics, financial strain, diet and cooking patterns, and present the opportunity for a food-energy nexus approach to address multiple Sustainable Development Goals (SDGs): achieving zero hunger (SDG 2) and universal affordable, modern and clean energy access (SDG 7) by 2030. Ensuring that LPG is affordable, accessible and meets the dietary and cooking needs of families should be a policy priority for helping improve food and energy security among the urban poor.

Pay-as-you-go liquefied petroleum gas supports sustainable clean cooking in Kenyan informal urban settlement during COVID-19 lockdown.

Approximately 2.8 billion people rely on polluting fuels (e.g. wood, kerosene) for cooking. With affordability being a key access barrier to clean cooking fuels, such as liquefied petroleum gas (LPG), pay-as-you-go (PAYG) LPG smart meter technology may help resource-poor households adopt LPG by allowing incremental fuel payments. To understand the potential for PAYG LPG to facilitate clean cooking, objective evaluations of customers' cooking and spending patterns are needed. This study uses novel smart meter data collected between January 2018-June 2020, spanning COVID-19 lockdown, from 426 PAYG LPG customers living in an informal settlement in Nairobi, Kenya to evaluate stove usage (e.g. cooking events/day, cooking event length). Seven semi-structured interviews were conducted in August 2020 to provide context for potential changes in cooking behaviours during lockdown. Using stove monitoring data, objective comparisons of cooking patterns are made with households using purchased 6 kg cylinder LPG in peri-urban Eldoret, Kenya. In Nairobi, 95% of study households continued using PAYG LPG during COVID-19 lockdown, with consumption increasing from 0.97 to 1.22 kg/capita/month. Daily cooking event frequency also increased by 60% (1.07 to 1.72 events/day). In contrast, average days/month using LPG declined by 75% during lockdown (17 to four days) among seven households purchasing 6 kg cylinder LPG in Eldoret. Interviewed customers reported benefits of PAYG LPG beyond fuel affordability, including safety, time savings and cylinder delivery. In the first study assessing PAYG LPG cooking patterns, LPG use was sustained despite a COVID-19 lockdown, illustrating how PAYG smart meter technology may help foster clean cooking access.