Biomass smoke exposure and somatic growth among children: The RESPIRE and CRECER prospective cohort studies in rural Guatemala.

BACKGROUND: Cooking-related biomass smoke is a major source of household air pollution (HAP) and an important health hazard. Prior studies identified associations between HAP exposure and childhood stunting; less is known for underweight and wasting. Few studies had personal HAP measurements. METHODS: 557 households in rural Guatemala were enrolled in the CRECER study, the follow-up study of the RESPIRE randomized intervention trial. They were assigned to three groups that received chimney stoves at different ages of the study children. Multiple personal carbon monoxide (CO) exposure measurements were used as proxies for HAP exposures. Children's heights and weights were measured from 24 to 60 months of age. Height-for-age z-score (HAZ), weight-for-age z-score (WAZ), and weight-for-height z-score (WHZ) were calculated based on the World Health Organization's Multicentre Growth Reference Study. HAZ, WAZ, and WHZ below -2 were classified as stunting, underweight, and wasting, respectively. Generalized linear models and mixed effects models were applied. RESULTS: 541 children had valid anthropometric data, among whom 488 (90.2 %) were stunted, 192 (35.5 %) were underweight, and 2 (0.3 %) were wasted. A 1 ppm higher average CO exposure was associated with a 0.21 lower HAZ (95 % CI: 0.17-0.25), a 0.13 lower WAZ (95 % CI: 0.10-0.17) and a 0.06 lower WHZ (95 % CI: 0.02-0.10).The associations for HAZ were stronger among boys (coefficient = -0.29, 95 % CI: -0.35 - -0.22) than among girls (coefficient = -0.15, 95 % CI: -0.20 - -0.10). A 1 ppm-year higher cumulative CO exposure was associated with a higher risk of moderate stunting among boys (OR = 1.27, 95 % CI: 1.05-1.59), but not among girls. DISCUSSION: In this rural Guatemalan population, higher HAP exposure was associated with lower HAZ and WAZ. The associations between HAP and HAZ/stunting were stronger among boys. Reducing HAP might benefit childhood somatic growth in rural populations of low-income countries.

Biomass Smoke Exposure and Atopy among Young Children in the Western Highlands of Guatemala: A Prospective Cohort Study.

Women and children in rural regions of low-income countries are exposed to high levels of household air pollution (HAP) as they traditionally tend to household chores such as cooking with biomass fuels. Early life exposure to air pollution is associated with aeroallergen sensitization and developing allergic diseases at older ages. This prospective cohort study assigned HAP-reducing chimney stoves to 557 households in rural Guatemala at different ages of the study children. The children's air pollution exposure was measured using personal CO diffusion tubes. Allergic outcomes at 4-5 years old were assessed using skin prick tests and International Study of Asthma and Allergies in Childhood (ISAAC)-based questionnaires. Children assigned to improved stoves before 6 months old had the lowest HAP exposure compared to the other groups. Longer exposure to the unimproved stoves was associated with higher risks of maternal-reported allergic asthma (OR = 2.42, 95% CI: 1.11-5.48) and rhinitis symptoms (OR = 2.01, 95% CI: 1.13-3.58). No significant association was found for sensitization to common allergens such as dust mites and cockroaches based on skin prick tests. Reducing HAP by improving biomass burning conditions might be beneficial in preventing allergic diseases among children in rural low-income populations.

Emissions Measurements from Household Solid Fuel Use in Haryana, India: Implications for Climate and Health Co-benefits.

A large concern with estimates of climate and health co-benefits of "clean" cookstoves from controlled emissions testing is whether results represent what actually happens in real homes during normal use. A growing body of evidence indicates that in-field emissions during daily cooking activities differ substantially from values obtained in laboratories, with correspondingly different estimates of co-benefits. We report PM2.5 emission factors from uncontrolled cooking (n = 7) and minimally controlled cooking tests (n = 51) using traditional chulha and angithi stoves in village kitchens in Haryana, India. Minimally controlled cooking tests (n = 13) in a village kitchen with mixed dung and brushwood fuels were representative of uncontrolled field tests for fine particulate matter (PM2.5), organic and elemental carbon (p > 0.5), but were substantially higher than previously published water boiling tests using dung or wood. When the fraction of nonrenewable biomass harvesting, elemental, and organic particulate emissions and modeled estimates of secondary organic aerosol (SOA) are included in 100 year global warming commitments (GWC100), the chulha had a net cooling impact using mixed fuels typical of the region. Correlation between PM2.5 emission factors and GWC (R2 = 0.99) implies these stoves are climate neutral for primary PM2.5 emissions of 8.8 ± 0.7 and 9.8 ± 0.9 g PM2.5/kg dry fuel for GWC20 and GWC100, respectively, which is close to the mean for biomass stoves in global emission inventories.

Increased air pollution exposure among the Chinese population during the national quarantine in 2020.

The COVID-19 quarantine in China is thought to have reduced ambient air pollution. The overall exposure of the population also depends, however, on indoor air quality and human mobility and activities. Here, by integrating real-time mobility data and a questionnaire survey on time-activity patterns during the pandemic, we show that despite a decrease in ambient PM2.5 during the quarantine, the total population-weighted exposure to PM2.5 considering both indoor and outdoor environments increased by 5.7 µg m-3 (95% confidence interval, 1.2-11.0 µg m-3). The increase in population-weighted exposure was mainly driven by a nationwide urban-to-rural population migration before the Spring Festival coupled with the freezing of the migration backward due to the quarantine, which increased household energy consumption and the fraction of people exposed to rural household air pollution indoors. Our analysis reveals an increased inequality of air pollution exposure during the quarantine and highlights the importance of household air pollution for population health in China.

Towards safe drinking water and clean cooking for all.

The public health community has tried for decades to show, through evidence-based research, that safe water, sanitation, and hygiene (WASH) and clean cooking fuels that reduce household air pollution are essential to safeguard health and save lives in low-income and middle-income countries. In the past 40 decades, there have been many innovations in the development of low-cost and efficacious technologies for WASH and household air pollution, but many of these technologies have been associated with disappointing health outcomes, often because low-income households have either not adopted, or inconsistently adopted, these technologies. In this Viewpoint, we argue that public health researchers (ourselves included) have had an oversimplified understanding of poverty; our work has not focused on insights into the lived experience of poverty, with its uncertainties, stresses from constant scarcity, and attendant fears. Such insights are central to understanding why technologies for safe water or clean cooking are unused by so many households that could benefit from them. We argue that, rather than improved versions of household-scale delivery models, transformative investments in safe water and clean cooking for all require utility-scale service models. Until then, research should focus on interim safe water and clean cooking options that are directed towards the utility-scale service model.

Individual and population level protection from particulate matter exposure by wearing facemasks.

Because of the severe air pollution in northern China, facemasks have gained popularity in this area in recent years. Although the results of previous studies have shown the effectiveness of wearing facemasks for intercepting particles, the individual differences and the overall health benefits of wearing facemasks have not been comprehensively documented. In this study, using both model and personal tests under various conditions, we test eight major brands of facemasks for their removal efficiencies (REs) of particulate matter (PM) in six size ranges (from 0.3 µm to >10 µm). The results are used to assess the overall exposure reduction at the individual and population levels in Beijing. We find significant differences in REs among PM sizes, facemask brands, pollution levels, and genders. Combining the information on the usage of various brands, facemask wearing rates, and PM2.5 concentrations in the ambient and indoor air in this area, we evaluate the overall effect of facemask wearing on PM2.5 exposure reduction. It is quantitatively demonstrated that because people spend most time indoors, facemask protection is limited. For facemask wearers, the overall exposure can be reduced by less than 20%, whereas the reduction rate is as low as 2.4 ± 1.6% for the entire adult populations even in the year with the highest level of pollution with an annual mean PM2.5 concentration of 102 ± 98 µg∙m-3. As a strategy of self-protection from long-term exposure to particulate matter, wearing facemasks outdoors is inferior to the installation of indoor air purifiers.

Boiled or Bottled: Regional and Seasonal Exposures to Drinking Water Contamination and Household Air Pollution in Rural China.

BACKGROUND: Inadequate access to safe drinking water remains a global health problem, particularly in rural areas. Boiling is the most commonly used form of point-of-use household water treatment (HWT) globally, although the use of bottled water in low- and middle-income countries (LMICs) is increasing rapidly. OBJECTIVES: We assessed the regional and seasonal prevalence of HWT practices (including bottled water use) in low-income rural areas in two Chinese provinces, evaluated the microbiological safety of drinking water and associated health outcomes, and estimated the air pollution burden associated with the use of solid fuels for boiling. METHODS: We conducted cross-sectional surveys and collected drinking water samples from 1,033 rural households in Guangxi and Henan provinces. Temperature sensors affixed to pots and electric kettles were used to corroborate self-reported boiling frequencies and durations, which were used to model household air pollution (HAP) in terms of estimated particulate matter ≤2.5µm in aerodynamic diameter (PM2.5) concentrations. RESULTS: Based on summer data collection in both provinces, after controlling for covariates, boiling with electric kettles was associated with the largest log reduction in thermotolerant coliforms (TTCs) (-0.66 log10 TTC most probable number/100mL), followed by boiling with pots (-0.58), and bottled water use (-0.39); all were statistically significant (p<0.001). Boiling with electric kettles was associated with a reduced risk of TTC contamination [risk ratio (RR)=0.25, p<0.001] and reported diarrhea (RR=0.80, p=0.672). TTCs were detected in 51% (n=136) of bottled water samples. For households boiling with biomass, modeled PM2.5 concentrations averaged 79 µg/m3 (standard deviation=21). DISCUSSION: Our findings suggest that where boiling is already common and electricity access is widespread, the promotion of electricity-based boiling may represent a pragmatic stop-gap means of expanding safe water access until centralized, or decentralized, treated drinking water is available; displacing biomass use for water boiling could also reduce HAP concentrations and exposures. Our results also highlight the risks of increasing bottled water use in rural areas, and its potential to displace other sources of safe drinking water, which could in turn hamper efforts in China and other LMICs toward universal and affordable safe water access. https://doi.org/10.1289/EHP7124.

The quest for improved air quality may push China to continue its CO2 reduction beyond the Paris Commitment.

China is challenged with the simultaneous goals of improving air quality and mitigating climate change. The "Beautiful China" strategy, launched by the Chinese government in 2020, requires that all cities in China attain 35 µg/m3 or below for annual mean concentration of PM2.5 (particulate matter with aerodynamic diameter less than 2.5 µm) by 2035. Meanwhile, China adopts a portfolio of low-carbon policies to meet its Nationally Determined Contribution (NDC) pledged in the Paris Agreement. Previous studies demonstrated the cobenefits to air pollution reduction from implementing low-carbon energy policies. Pathways for China to achieve dual targets of both air quality and CO2 mitigation, however, have not been comprehensively explored. Here, we couple an integrated assessment model and an air quality model to evaluate air quality in China through 2035 under the NDC scenario and an alternative scenario (Co-Benefit Energy [CBE]) with enhanced low-carbon policies. Results indicate that some Chinese cities cannot meet the PM2.5 target under the NDC scenario by 2035, even with the strictest end-of-pipe controls. Achieving the air quality target would require further reduction in emissions of multiple air pollutants by 6 to 32%, driving additional 22% reduction in CO2 emissions relative to the NDC scenario. Results show that the incremental health benefit from improved air quality of CBE exceeds 8 times the additional costs of CO2 mitigation, attributed particularly to the cost-effective reduction in household PM2.5 exposure. The additional low-carbon energy polices required for China's air quality targets would lay an important foundation for its deep decarbonization aligned with the 2 °C global temperature target.

Incentivizing Elimination of Biomass Cooking Fuels with a Reversible Commitment and a Spare LPG Cylinder.

In India, approximately 480,000 deaths occur annually from exposure to household air pollution from the use of biomass cooking fuels. Displacing biomass use with clean fuels, such as liquefied petroleum gas (LPG), can help reduce these deaths. Through government initiatives, most Indian households now own an LPG stove and one LPG cylinder. Many households, however, continue to regularly use indoor biomass-fueled mud stoves (chulhas) alongside LPG. Focusing on this population in rural Maharashtra, India, this study (N = 186) tests the effects of conditioning a sales offer for a spare LPG cylinder on a reversible commitment requiring initially disabling indoor chulhas. We find that almost all relevant households (>98%) were willing to accept this commitment. Indoor chulha use decreased by 90% (95% CI = 80% to 101%) when the sales offer included the commitment, compared to a 23% decrease (95% CI = 14% to 32%) without it. For both treatment groups, we find that 80% purchased the spare cylinder at the end of the study.

Marriage-based pilot clean household fuel intervention in India for improved pregnancy outcomes.

INTRODUCTION: Health interventions often target pregnant women and their unborn children. Interventions in rural India targeting pregnant women, however, often do not cover the critical early windows of susceptibility during the first trimester and parts of the second trimester. This pilot seeks to determine if targeting newlyweds could protect entire pregnancies with a clean stove and fuel intervention. METHODS: We recruited 50 newlywed couples who use biomass as a cooking fuel into a clean cooking intervention that included a liquefied petroleum gas (LPG) stove, two gas cylinders, a table to place the stove on and health education. We first evaluated whether community health workers in this region could identify and recruit couples at marriage. We quantified how many additional days of pregnancy could be covered by an intervention if we recruited at marriage versus recruiting after detection of pregnancy. RESULTS: On average, we identified and visited newlywed couples within 40 (SD 21) days of marriage. Of the 50 couples recruited, 25 pregnancies and 18 deliveries were identified during this 1-year study. Due to challenges securing fuel from the LPG supply system, not all couples received their intervention prior to pregnancy. Regardless, couples recruited in the marriage arm had substantially more days with the intervention than couples recruited into a similar arm recruited at pregnancy (211 SD 46 vs 120 SD 45). At scale, a stove intervention targeting new marriages would cover about twice as many weeks of first pregnancies as an intervention recruiting after detection of pregnancy. CONCLUSIONS: We were able to recruit in early marriage using existing community health workers. Households recruited early in marriage had more days with clean fuel coverage than those recruited at pregnancy. Our findings indicate that recruitment at marriage is feasible and warrants further exploration for stove and other interventions targeting pregnancy-related outcomes.

Global impact of atmospheric arsenic on health risk: 2005 to 2015.

Arsenic is a toxic pollutant commonly found in the environment. Most of the previous studies on arsenic pollution have primarily focused on arsenic contamination in groundwater. In this study, we examine the impact on human health from atmospheric arsenic on the global scale. We first develop an improved global atmospheric arsenic emission inventory and connect it to a global model (Goddard Earth Observing System [GEOS]-Chem). Model evaluation using observational data from a variety of sources shows the model successfully reproduces the spatial distribution of atmospheric arsenic around the world. We found that for 2005, the highest airborne arsenic concentrations were found over Chile and eastern China, with mean values of 8.34 and 5.63 ng/m3, respectively. By 2015, the average atmospheric arsenic concentration in India (4.57 ng/m3) surpassed that in eastern China (4.38 ng/m3) due to the fast increase in coal burning in India. Our calculation shows that China has the largest population affected by cancer risk due to atmospheric arsenic inhalation in 2005, which is again surpassed by India in 2015. Based on potential exceedance of health-based limits, we find that the combined effect by including both atmospheric and groundwater arsenic may significantly enhance the risks, due to carcinogenic and noncarcinogenic effects. Therefore, this study clearly implies the necessity in accounting for both atmospheric and groundwater arsenic in future management.

Energy and air pollution benefits of household fuel policies in northern China.

In addition to many recent actions taken to reduce emissions from energy production, industry, and transportation, a new campaign substituting residential solid fuels with electricity or natural gas has been launched in Beijing, Tianjin, and 26 other municipalities in northern China, aiming at solving severe ambient air pollution in the region. Quantitative analysis shows that the campaign can accelerate residential energy transition significantly, and if the planned target can be achieved, more than 60% of households are projected to remove solid fuels by 2021, compared with fewer than 20% without the campaign. Emissions of major air pollutants will be reduced substantially. With 60% substitution realized, emission of primary PM2.5 and contribution to ambient PM2.5 concentration in 2021 are projected to be 30% and 41% of those without the campaign. With 60% substitution, average indoor PM2.5 concentrations in living rooms in winter are projected to be reduced from 209 (190 to 230) µg/m3 to 125 (99 to 150) µg/m3 The population-weighted PM2.5 concentrations can be reduced from 140 µg/m3 in 2014 to 78 µg/m3 or 61 µg/m3 in 2021 given that 60% or 100% substitution can be accomplished. Although the original focus of the campaign was to address ambient air quality, exposure reduction comes more from improved indoor air quality because ∼90% of daily exposure of the rural population is attributable to indoor air pollution. Women benefit more than men.

Table of contents Ujjwala 2. 0 from access to sustained usage

By September 2019, some 80 million poor households will have been connected to LPG since 2015 through the national programme, Pradhan Mantri Ujjwala Yojana (Ujjwala). This is in addition to "normal" growth in LPG connections amounting to approximately 40 million households. By any account, this is a remarkable achievement, bringing total households with LPG connections from about 60% of the country early this decade to some 95% by the beginning of the next. Connection, however, does not mean full usage and many new Ujjwala households and others continue to use significant amounts of biomass fuel, with consequent impacts on the health of village populations from the smoke. In addition, it is now well established that smoke from household biomass use is the largest single source of outdoor air pollution in the country, although of course not the only one.3 Its continued use thus is a problem for all Indians. How to continue to fulfill the promise of Ujjwala in its second phase, here called Ujjwala 2.0, is an important policy discussion in the country.

Advanced household heat pumps for air pollution control: A pilot field study in Ulaanbaatar, the coldest capital city in the world.

Ulaanbaatar - the coldest capital in the world - is home to half of Mongolia's population, much of which uses coal for household heating, contributing to high wintertime air pollution. We piloted two-stage air-to-air heat pumps in 2017, when temperatures dropped to -39 °C. These heat pumps were reliable and efficient, with an average coefficient of performance of 1.86 on the coldest days. Heat pumps' recurrent costs were similar to those of coal stoves and lower than those of resistive heaters.

Indian annual ambient air quality standard is achievable by completely mitigating emissions from household sources.

Exposures to ambient and household fine-particulate matter (PM2.5) together are among the largest single causes of premature mortality in India according to the Global Burden of Disease Studies (GBD). Several recent investigations have estimated that household emissions are the largest contributor to ambient PM2.5 exposure in the country. Using satellite-derived district-level PM2.5 exposure and an Eulerian photochemical dispersion model CAMx (Comprehensive Air Quality Model with Extensions), we estimate the benefit in terms of population exposure of mitigating household sources--biomass for cooking, space- and water-heating, and kerosene for lighting. Complete mitigation of emissions from only these household sources would reduce India-wide, population-weighted average annual ambient PM2.5 exposure by 17.5, 11.9, and 1.3%, respectively. Using GBD methods, this translates into reductions in Indian premature mortality of 6.6, 5.5, and 0.6%. If PM2.5 emissions from all household sources are completely mitigated, 103 (of 597) additional districts (187 million people) would meet the Indian annual air-quality standard (40 µg m-3) compared with baseline (2015) when 246 districts (398 million people) met the standard. At 38 µg m-3, after complete mitigation of household sources, compared with 55.1 µg m-3 at baseline, the mean annual national population-based concentration would meet the standard, although highly polluted areas, such as Delhi, would remain out of attainment. Our results support expansion of programs designed to promote clean household fuels and rural electrification to achieve improved air quality at regional scales, which also has substantial additional health benefits from directly reducing household air pollution exposures.

Promoting LPG usage during pregnancy: A pilot study in rural Maharashtra, India.

Household air pollution from the combustion of biomass and coal is estimated to cause approximately 780,000 premature deaths a year in India. The government has responded by promoting uptake of liquefied petroleum gas (LPG) by tens of millions of poor rural families. Many poor households with new LPG stoves, however, continue to partially use traditional smoky chulhas. Our primary objective was to evaluate three strategies to transition pregnant women in rural Maharashtra to exclusive use of LPG for cooking. We also measured reductions in kitchen concentrations of PM2.5 before and after our interventions. Our core intervention was a free stove, 2 free LPG cylinders (one on loan until delivery), and repeated health messaging. We measured stove usage of both the traditional and intervention stoves until delivery. In households that received the core intervention, an average of 66% days had no indoor cooking on a chulha. In an adjacent area, we evaluated a conditional cash transfer (CCT) based on usage of LPG in addition to the core intervention. Results were less successful, due to challenges implementing the CCT. Pregnant women in a third nearby area received the core intervention plus a maximum of one 14.2 kg cylinder per month of free fuel. In their homes, 90% of days had no indoor cooking on a chulha. On average, exclusive LPG use decreased kitchen concentrations of PM2.5 by approximately 85% (from 520 to 72 µg/m3). 85% of participating households agreed to pay the deposit on the 2nd cylinder. This high purchase rate suggests they valued how the second cylinder permitted continuous LPG supply. A program to increase access to second cylinders may, thus, be a straightforward way to encourage use of clean fuels in rural areas.

Extraintestinal Pathogenic Escherichia coli and Antimicrobial Drug Resistance in a Maharashtrian Drinking Water System.

Although access to piped drinking water continues to increase globally, information on the prevalence and clonal composition of coliforms found in piped water systems in low-resource settings remains limited. From June to July 2016, we examined Escherichia coli isolates in domestic water from the distribution system in Alibag, a small town in India. We analyzed the isolates for drug resistance and genotyped them by multilocus sequence typing. Of 147 water samples, 51 contained coliforms, and 19 (37%) of the 51 were biochemically confirmed to contain E. coli. These samples contained 104 E. coli isolates-all resistant to ampicillin. Resistance to ceftazidime was observed in 52 (50%) isolates, cefotaxime in 59 (57%), sulfamethoxazole-trimethoprim in 46 (44%), ciprofloxacin in 30 (29%), and gentamicin in two (2%). Thirty-eight (36%) belonged to sequence types recognized as extraintestinal pathogenic E. coli (ExPEC); 19 (50%) of these 38 ExPEC belonged to known uropathogenic E. coli lineages. This exploratory field research shows the extent to which "improved" drinking water is a potential source of E. coli strains capable of causing extraintestinal infections.

Sanitation in Rural India: Exploring the Associations between Dwelling Space and Household Latrine Ownership.

In 2017, the Joint Monitoring Programme estimated that 520 million people in India were defecating in the open every day. This is despite efforts made by the government, Non-Governmental Organizations (NGOs), and multilaterals to improve latrine coverage throughout India. We hypothesize that this might be because current interventions focus mostly on individual-level determinants, such as attitudes and beliefs, instead of considering all possible social determinants of latrine ownership. Given this, we ask two questions: what is the association between the amount of dwelling space owned by households in rural India and their likelihood of toilet ownership and what proportion of the variation in household latrine ownership is attributable to villages and states? We used multilevel modeling and found significant associations between the amount of household dwelling space and the likelihood of latrine ownership. Furthermore, considerable variation in latrine ownership is attributable to villages and states, suggesting that additional research is required to elucidate the contextual effects of villages and states on household latrine ownership. Thus, sanitation interventions should consider household dwelling space and village and state context as important social determinants of latrine ownership in rural India. Doing so could bolster progress towards Sustainable Development Goal (SDG) 6.

Let the "A" in WASH Stand for Air: Integrating Research and Interventions to Improve Household Air Pollution (HAP) and Water, Sanitation and Hygiene (WaSH) in Low-Income Settings.

BACKGROUND: Research often suffers from overspecialization, a practice nurtured in academia and reinforced by funders. Indeed, investigators in household air pollution (HAP) and water, sanitation and hygiene (WaSH), working in poor parts of the world, rarely interact despite having similar training and using similar methods to evaluate interventions in the same vulnerable populations. Disappointing results from recent trials of improved cookstoves and traditional approaches to WaSH suggest the need for alternative approaches. OBJECTIVES: We argue that bringing these two areas together would improve the effectiveness and efficiency of interventions to reduce the massive disease burden associated with HAP and poor WaSH, including pneumonia and diarrhea, the leading killers of young children in low-income countries. RESULTS: HAP and WaSH face similar challenges in designing, implementing, and securing the sustained and exclusive use of scalable interventions such as clean fuel and water. DISCUSSION: Research can advance greater coordination of these areas by demonstrating their interactions and wider impacts on well-being as well as the potential for programmatic synergies. Integrated solutions to clean households and communities can benefit from the contribution in multiple disciplines, including economics and policy analysis; business and finance; engineering and technology; lab sciences, environmental health, and biomedical sciences; and behavioral and implementation sciences. CONCLUSION: There are compelling reasons to overcome the artificial and unproductive segregation of HAP and WaSH. Researchers should encourage integration by expanding the scope of their collaborations and projects. Policy makers, funders, and implementers can help by supporting comprehensive solutions, encouraging innovation, and requiring rigorous evaluations of their effects. https://doi.org/10.1289/EHP4752.