Long-standing LPG subsidies, cooking fuel stacking, and personal exposure to air pollution in rural and peri-urban Ecuador

Impact of randomly assigned "pay-as-you-go" liquefied petroleum gas prices on energy use for cooking: Experimental pilot evidence from rural Rwanda

The disease burden related to air pollution from traditional solid-fuel cooking practices in low- and middle-income countries impacts millions of people globally. Although the use of liquefied petroleum gas (LPG) fuel for cooking can meaningfully reduce household air pollution concentrations, major barriers, including affordability and accessibility, have limited widespread adoption. Using a randomized controlled trial, our objective was to evaluate the association between the cost and use of LPG among 23 rural Rwandan households. We provided a 2-burner LPG stove with accessories and incorporated a "pay-as-you-go" (PAYG) LPG service model that included fuel delivery. PAYG services remove the large up-front cost of cylinder refills by integrating "smart meter" technology that allows participants to pay in incremental amounts, as needed. We assigned three randomized discounted prices for LPG to each household at ~4-week intervals over a 12-week period. We modeled the relationship between randomized PAYG LPG price and use (standardized to monthly periods), analyzing effect modification by relative household wealth. A 1000 Rwandan Franc (about 1 USD at the time of the study) increase in LPG price/kg was associated with a 4.1 kg/month decrease in use (95% confidence interval [CI]: -6.7, -1.6; n=69 observations). Wealth modified this association; we observed a 9.7 kg/month reduction (95% CI: -14.8, -4.5) among wealthier households and a 2.5 kg/month reduction (95% CI: -5.3, 0.3) among lower-wealth households (p-interaction=0.01). The difference in price sensitivity was driven by higher LPG use among wealthier households at more heavily discounted prices; from an 80% to 10% discount, wealthy households used 17.5 to 5.3 kg/month and less wealthy households used 6.2 to 3.1 kg/month. Our pilot-level experimental evidence of PAYG LPG in a rural low-resource setting suggests that further exploration of subsidized pricing varied by household wealth is needed to ensure future policy initiatives can achieve targets without exacerbating inequities.

In praise of fossil fuel subsidies (for cooking)

Households that burn biomass in inefficient open fires - a practice that results in $1.6 trillion in global damages from health impacts and climate-altering emissions yearly - are often unable to access cleaner alternatives, like gas, which is widely available but unaffordable, or electricity, which is unattainable for many due to insufficient supply and reliability of electricity services. Governments are often reluctant to make gas affordable. We argue that condemnation of all fossil fuel subsidies is short-sighted and does not adequately consider subsidizing gas for cooking as a potential strategy to improve public health and reduce greenhouse gas emissions.

Clearing the Air: Gas Stove Emissions and Direct Health Effects

Gas range use has direct health effects-beyond those from climate change related to fossil fuels. If kitchens are not well ventilated, benzene, nitrogen dioxide, and other VOCs may reach levels known to harm health.

Resilient clean cooking: Maintaining household clean cooking in Ecuador during the COVID-19 pandemic

Decades of government subsidies for LPG and electricity have facilitated near-universal clean cooking access and use in Ecuador, placing the nation ahead of most other peer low- and middle-income countries. The widespread socio-economic impacts of the COVID-19 pandemic has threatened the resilience of clean cooking systems globally, including by altering households' ability to purchase clean fuels and policymakers' considerations about continuing subsidy programs. As such, assessing the resilience of clean cooking in Ecuador during the pandemic can offer important lessons for the international community, especially other countries looking to ensure resilient transitions to clean cooking. We study household energy use patterns using interviews, newspaper reports, government data on household electricity and LPG consumption, and household surveys [N = 200 across two rounds]. The LPG and electricity distribution systems experienced occasional disruptions to cylinder refill delivery and meter reading processes, respectively, which were associated with pandemic-related mobility restrictions. However, for the most part, supply and distribution activities by private and public companies continued without fundamental change. Survey participants reported increases in unemployment and reductions in household income as well as increased use of polluting biomass as a secondary fuel. Ecuador's LPG and electricity distribution systems were resilient throughout the pandemic, with only minimal interruption of the widespread provision of low-cost clean cooking fuels. Our findings inform the global audience concerned about the resilience of clean household energy use on the potential for clean fuel subsidies to facilitate continued clean cooking even during the COVID-19 pandemic.

Widespread Clean Cooking Fuel Scale-Up and under-5 Lower Respiratory Infection Mortality: An Ecological Analysis in Ecuador, 1990-2019

BACKGROUND

Nationwide household transitions to the use of clean-burning cooking fuels are a promising pathway to reducing under-5 lower respiratory infection (LRI) mortality, the leading cause of child mortality globally, but such transitions are rare and evidence supporting an association between increased clean fuel use and improved health is limited.

OBJECTIVES

This study aimed to investigate the association between increased primary clean cooking fuel use and under-5 LRI mortality in Ecuador between 1990 and 2019.

METHODS

We documented cooking fuel use and cause-coded child mortalities at the canton (county) level in Ecuador from 1990 to 2019 (in four periods, 1988-1992, 1999-2003, 2008-2012, and 2015-2019). We characterized the association between clean fuel use and the rate of under-5 LRI mortalities at the canton level using quasi-Poisson generalized linear and generalized additive models, accounting for potential confounding variables that characterize wealth, urbanization, and child health care and vaccination rates, as well as canton and period fixed effects. We estimated averted under-5 LRI mortalities accrued over 30 y by predicting a counterfactual count of canton-period under-5 LRI mortalities were clean fuel use to not have increased and comparing with predicted canton-period under-5 LRI mortalities from our model and observed data.

RESULTS

From 1990 to 2019, the proportion of households primarily using a clean cooking fuel increased from 59% to 95%, and under-5 LRI mortality fell from 28 to 7 per 100,000 under-5 population. Canton-level clean fuel use was negatively associated with under-5 LRI mortalities in linear and nonlinear models. The nonlinear association suggested a threshold at approximately 60% clean fuel use, above which there was a negative association. Increases in clean fuel use between 1990 and 2019 were associated with an estimated 7,300 averted under-5 LRI mortalities (95% confidence interval: 2,600, 12,100), accounting for nearly 20% of the declines in under-5 LRI mortality observed in Ecuador over the study period.

DISCUSSION

Our findings suggest that the widespread household transition from using biomass to clean-burning fuels for cooking reduced under-5 LRI mortalities in Ecuador over the last 30 y. https://doi.org/10.1289/EHP11016.

The feasibility and acceptability of clean fuel use among rural households. A pilot study in Central Ghana

Background: 76% of the population in Ghana uses solid fuels as their primary source of cooking energy, including 41.3% firewood and 31.5% charcoal. Consequently, household air pollution (HAP) continues to be the leading risk factor for the majority of illness burden in the country. In the past, aggressive LPG distribution and adoption schemes have been implemented to reduce HAP in Ghana. Nevertheless, just 22% of Ghanaian households utilize LPG for cooking. Aims. The purpose of this study was to determine the viability and acceptability of four clean fuels among rural households in central Ghana, both separately and in combination. Methods: Quantitative and qualitative methods were used to conduct this study. The Kintampo Health Demographic Surveillance System was used to randomly pick ten homes who exclusively utilized biomass fuel. For each family (n = 10), we gave four stove and fuel combinations that were both clean. The stoves were utilized for two weeks, and free fuel was supplied. After each two-week trial period, interviews were conducted to gauge stove acceptance, with an emphasis on finding the specific energy requirements that each stove satisfied. Conclusions. LPG and ethanol stoves were the most popular among rural families, according to our data. In comparison to Mimi Moto and electric induction stoves, the two stoves were favoured because they were easier to use and clean, cooked faster, were deemed safer, and enabled a variety of cooking styles. Participants’ stove preferences appear to be primarily influenced by two domains: 1) realizing the benefits of clean stove technology and 2) overcoming early anxiety of clean stove use, particularly LPG.

Comparing human exposure to fine particulate matter in low and high-income countries: A systematic review of studies measuring personal PM2.5 exposure

BACKGROUND

Due to the adverse health effects of air pollution, researchers have advocated for personal exposure measurements whereby individuals carry portable monitors in order to better characterise and understand the sources of people's pollution exposure.

OBJECTIVES

The aim of this systematic review is to assess the differences in the magnitude and sources of personal PM2.5 exposures experienced between countries at contrasting levels of income.

METHODS

This review summarised studies that measured participants personal exposure by carrying a PM2.5 monitor throughout their typical day. Personal PM2.5 exposures were summarised to indicate the distribution of exposures measured within each country income category (based on low (LIC), lower-middle (LMIC), upper-middle (UMIC), and high (HIC) income countries) and between different groups (i.e. gender, age, urban or rural residents).

RESULTS

From the 2259 search results, there were 140 studies that met our criteria. Overall, personal PM2.5 exposures in HICs were lower compared to other countries, with UMICs exposures being slightly lower than exposures measured in LMICs or LICs. 34% of measured groups in HICs reported below the ambient World Health Organisation 24-h PM2.5 guideline of 15 μg/m3, compared to only 1% of UMICs and 0% of LMICs and LICs. There was no difference between rural and urban participant exposures in HICs, but there were noticeably higher exposures recorded in rural areas compared to urban areas in non-HICs, due to significant household sources of PM2.5 in rural locations. In HICs, studies reported that secondhand smoke, ambient pollution infiltrating indoors, and traffic emissions were the dominant contributors to personal exposures. While, in non-HICs, household cooking and heating with biomass and coal were reported as the most important sources.

CONCLUSION

This review revealed a growing literature of personal PM2.5 exposure studies, which highlighted a large variability in exposures recorded and severe inequalities in geographical and social population subgroups.

Assessing the Effects of Stove Use Patterns and Kitchen Chimneys on Indoor Air Quality during a Multiyear Cookstove Randomized Control Trial in Rural India

We conducted indoor air quality (IAQ) measurements during a multiyear cookstove randomized control trial in two rural areas in northern and southern India. A total of 1205 days of kitchen PM_2.5 were measured in control and intervention households during six ∼3 month long measurement periods across two study locations. Stoves used included traditional solid fuel (TSF), improved biomass, and liquefied petroleum gas (LPG) models. Intent-to-treat analysis indicates that the intervention reduced average 24 h PM_2.5 and black carbon in only one of the two follow-up measurement periods in both areas, suggesting mixed effectiveness. Average PM_2.5 levels were ∼50% lower in households with LPG (for exclusive LPG use: >75% lower) than in those without LPG. PM_2.5 was 66% lower in households making exclusive use of an improved chimney stove versus a traditional chimney stove and TSF-exclusive kitchens with a built-in chimney had ∼60% lower PM_2.5 than those without a chimney, indicating that kitchen ventilation can be as important as the stove technology in improving IAQ. Diurnal trends in real-time PM_2.5 indicate that kitchen chimneys were especially effective at reducing peak concentrations, which leads to decreases in daily PM_2.5 in these households. Our data demonstrate a clear hierarchy of IAQ improvement in real world, "stove-stacking" households, driven by different stove technologies and kitchen characteristics.

Household Air Pollution Concentrations after Liquefied Petroleum Gas Interventions in Rural Peru: Findings from a One-Year Randomized Controlled Trial Followed by a One-Year Pragmatic Crossover Trial

BACKGROUND

Household air pollution (HAP) from biomass fuel combustion remains a leading environmental risk factor for morbidity worldwide.

OBJECTIVE

Measure the effect of liquefied petroleum gas (LPG) interventions on HAP exposures in Puno, Peru.

METHODS

We conducted a 1-y randomized controlled trial followed by a 1-y pragmatic crossover trial in 180 women age 25-64 y. During the first year, intervention participants received a free LPG stove, continuous fuel delivery, and regular behavioral messaging, whereas controls continued their biomass cooking practices. During the second year, control participants received a free LPG stove, regular behavioral messaging, and vouchers to obtain LPG tanks from a nearby distributor, whereas fuel distribution stopped for intervention participants. We collected 48-h kitchen area concentrations and personal exposures to fine particulate matter (PM) with aerodynamic diameter ≤ 2.5 μ m (PM 2.5 ), black carbon (BC), and carbon monoxide (CO) at baseline and 3-, 6-, 12-, 18-, and 24-months post randomization.

RESULTS

Baseline mean  [ ± standard deviation  ( SD ) ] PM 2.5 (kitchen area concentrations 1,220 ± 1,010 vs. 1,190 ± 880   μ g / m 3 ; personal exposure 126 ± 214 vs. 104 ± 100   μ g / m 3 ), CO (kitchen 53 ± 49 vs. 50 ± 41  ppm ; personal 7 ± 8 vs. 7 ± 8  ppm ), and BC (kitchen 180 ± 120 vs. 210 ± 150   μ g / m 3 ; personal 19 ± 16 vs. 21 ± 22   μ g / m 3 ) were similar between control and intervention participants. Intervention participants had consistently lower mean  ( ± SD ) concentrations at the 12-month visit for kitchen (41 ± 59   μ g / m 3 , 3 ± 6   μ g / m 3 , and 8 ± 13  ppm ) and personal exposures (26 ± 34   μ g / m 3 , 2 ± 3   μ g / m 3 , and 3 ± 4  ppm ) to PM 2.5 , BC, and CO when compared to controls during the first year. In the second year, we observed comparable HAP reductions among controls after the voucher-based intervention for LPG fuel was implemented (24-month visit PM 2.5 , BC, and CO kitchen mean concentrations of 34 ± 74   μ g / m 3 , 3 ± 5   μ g / m 3 , and 6 ± 6  ppm and personal exposures of 17 ± 15   μ g / m 3 , 2 ± 2   μ g / m 3 , and 3 ± 4  ppm , respectively), and average reductions were present among intervention participants even after free fuel distribution stopped (24-month visit PM 2.5 , BC, and CO kitchen mean concentrations of 561 ± 1,251   μ g / m 3 , 82 ± 124   μ g / m 3 , and 23 ± 28  ppm and personal exposures of 35 ± 38   μ g / m 3 , 6 ± 6   μ g / m 3 , and 4 ± 5  ppm , respectively).

DISCUSSION

Both home delivery and voucher-based provision of free LPG over a 1-y period, in combination with provision of a free LPG stove and longitudinal behavioral messaging, reduced HAP to levels below 24-h World Health Organization air quality guidelines. Moreover, the effects of the intervention on HAP persisted for a year after fuel delivery stopped. Such strategies could be applied in LPG programs to reduce HAP and potentially improve health. https://doi.org/10.1289/EHP10054.

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.

Mutagenicity- and pollutant-emission factors of pellet-fueled gasifier cookstoves: Comparison with other combustion sources

Emissions from solid-fuel burning cookstoves are associated with 3 to 4 million premature deaths annually and contribute significantly to impacts on climate. Pellet-fueled gasifier stoves have some emission factors (EFs) approaching those of gas-fuel (liquid petroleum gas) stoves; however, their emissions have not been evaluated for biological effects. Here we used a new International Organization for Standardization (ISO) testing protocol to determine pollutant- and mutagenicity-EFs for a stove designed for pellet fuel, the Mimi Moto, and for two other forced-draft stoves, Xunda and Philips HD4012, burning pellets of hardwood or peanut hulls. The Salmonella assay-based mutagenicity-EFs (revertants/megajouledelivered) spanned three orders of magnitude and correlated highly (r = 0.99; n = 5) with EFs of the sum of 32 particle-phase polycyclic aromatic hydrocarbons (PAHs). The Mimi Moto/hardwood pellet combination had total-PAH- and mutagenicity-EFs 99.2 and 96.6% lower, respectively, compared to data published previously for the Philips stove burning non-pelletized hardwood, and 100 and 99.8% lower, respectively, compared to those of a wood-fueled three-stone fire. The Xunda burning peanut hull pellets had the highest fuel energy-based mutagenicity-EF (revertants/megajoulethermal) of the pellet stove/fuel combinations tested, which was between that of diesel exhaust, a known human carcinogen, and a natural-draft wood stove. Although the Mimi Moto burning hardwood pellets had the lowest fuel energy-based mutagenicity-EF, this value was between that of utility coal and utility wood boilers. This advanced stove/fuel combination has the potential to greatly reduce emissions in contrast to a traditional stove, but adequate ventilation is required to approach acceptable levels of indoor air quality.