Impacts of stove use patterns and outdoor air quality on household air pollution and cardiovascular mortality in southwestern China

Does the household clean energy transition benefit the mental health of the elderly in rural China? Evidence from China health and retirement longitudinal study

Clean energy transition has become a key strategy in combating global air pollution. In 2017, China launched its "coal-to-gas" policy, which provided subsidies to households for their clean energy transition. While debates on this policy focus mainly on safety and cost concerns, few studies have examined the causal relationship between energy transition and its health benefits, particularly mental health. Using data from the China Health and Retirement Longitudinal Survey (CHARLS), this paper employs a difference-in-differences (DID) approach to estimate the impact of the "coal-to-gas" policy on the mental health of the rural elderly in China. The findings indicate that the policy significantly improved the cognitive status of the elderly, especially episodic memory, which saw a 10.4% increase relative to the sample mean. The policy also significantly boosted the proportion of households using clean cooking fuels by 5.8%. Further analysis suggests that the improved sleep quality from reduced indoor air pollution by household energy transition, as a mechanism, could explain these results. This study provides a timely assessment of the policy's effectiveness, highlighting the importance of indoor air pollution control by household energy transition.

Individual and joint exposures to PM2.5 constituents and mortality risk among the oldest-old in China

Cohort evidence linking long-term survival of older adults with exposure to fine particulate matter (PM2.5) constituents remains scarce in China. By constructing a dynamic cohort based on the Chinese Longitudinal Healthy Longevity Study, we aimed to assess the individual and joint associations of major PM2.5 constituents with all-cause death in Chinese oldest-old (.80 years) adults. Time-dependent Cox proportional hazards models were adopted to estimate death risks of long-term exposure to PM2.5 constituents. Among 14,884 participants, totaling 56,342 person-years of follow-up, 12,346 deaths were identified. The highest mortality risk associated with an interquartile range (IQR) increase in exposure was 1.081 (95% confidence interval [CI]: 1.055-1.108) for sulfate (IQR=4.1 μg m-3), followed by 1.078 (95% CI: 1.056-1.101) for black carbon (IQR=1.6 μg m-3), 1.056 (95% CI: 1.028-1.084) for ammonium (IQR=3.2 μg m-3), 1.050 (95% CI: 1.021-1.080) for nitrate (IQR=5.8 μg m-3), and 1.049 (95% CI: 1.024-1.074) for organic matter (IQR=10.3 μg m-3). In joint exposure, each IQRequivalent rise of all five PM2.5 constituents was associated with an 8.2% (95% CI: 4.0%-12.6%) increase in mortality risk. The weight analysis indicated the predominant role of sulfate and black carbon in driving PM2.5-related mortality. Octogenarians (aged 80-89 years) and rural dwellers were at significantly greater risk of mortality from individual and joint exposures to PM2.5 constituents. This study suggests that later-life exposure to PM2.5 constituents, particularly sulfate and black carbon, may curtail long-term survival of the oldest-old in China.

Household residential energy choices in green transition: insights from a household survey in rural China

It has been widely recognized that accelerating green residential energy transition from traditional solid fuels (biomass and coal) to clean and high-efficient energy sources is critical for rural sustainable development. However, little attention has been paid to estimate panel data discrete choice models to analyze the dynamic behavior information of individual households in the process of energy transition. Hence, this paper investigates green residential energy transition using a panel dataset from 3308 rural households in eight provinces of China in 2015 and 2018. The results show that although traditional solid biomass still plays a dominating role in rural residential energy choice, fuel switching from solid fuels to modern clean energy alternatives is taking place. Off-farm employment plays an important role in the transition towards more sustainable energy sources, as households with off-farm employed heads and higher off-farm income level are highly likely to choose superior energy alternatives other than traditional biomass. Besides, the educational level of the household head and household location are also important influencing factors of household residential energy choices. Based on these findings, this paper suggests that job creation in non-farm sectors should be given a priority in future policy design to promote rural green energy transition in residential sector. North-south differences should be taken into account, whereas more policy options for optimizing biomass energy use should be explored.

Household Air Pollution Interventions to Improve Health in Low- and Middle-Income Countries: An Official American Thoracic Society Research Statement

Background: An estimated 3 billion people, largely in low- and middle-income countries, rely on unclean fuels for cooking, heating, and lighting to meet household energy needs. The resulting exposure to household air pollution (HAP) is a leading cause of pneumonia, chronic lung disease, and other adverse health effects. In the last decade, randomized controlled trials of clean cooking interventions to reduce HAP have been conducted. We aim to provide guidance on how to interpret the findings of these trials and how they should inform policy makers and practitioners.Methods: We assembled a multidisciplinary working group of international researchers, public health practitioners, and policymakers with expertise in household air pollution from within academia, the American Thoracic Society, funders, nongovernmental organizations, and global organizations, including the World Bank and the World Health Organization. We performed a literature search, convened four sessions via web conference, and developed consensus conclusions and recommendations via the Delphi method.Results: The committee reached consensus on 14 conclusions and recommendations. Although some trials using cleaner-burning biomass stoves or cleaner-cooking fuels have reduced HAP exposure, the committee was divided (with 55% saying no and 45% saying yes) on whether the studied interventions improved measured health outcomes.Conclusions: HAP is associated with adverse health effects in observational studies. However, it remains unclear which household energy interventions reduce exposure, improve health, can be scaled, and are sustainable. Researchers should engage with policy makers and practitioners working to scale cleaner energy solutions to understand and address their information needs.

Emissions of nitrated and oxygenated polycyclic aromatic hydrocarbons bound to coarse particles from solid fuel combustion

Parent polycyclic aromatic hydrocarbons (PAHs) emitted by residential sector have been well studied, however, data on PAHs derivatives such as nitrated PAHs (nPAHs) and oxygenated PAHs (oPAHs) are scarce. In this study, emission factors (EFs) of PM10-bound nPAHs and oPAHs from the combustion of eight different solid fuels in three different stoves in rural homes were measured in field, and a total of twelve fuel-stove combinations were included. Results showed that the field-based EFs for different fuel-stove combinations varied over three orders of magnitude, which ranged from 3.3 to 514 μg/kg and from 0.1 to 214 mg/kg for nPAHs and oPAHs, respectively. Biomass burning had 2.2 and 14.8 times higher EFs values of nPAHs and oPAHs compared with coal burning. The size distribution pattern of PAHs derivatives confirmed that they prefer to bind to fine particles. The composition profiles of nPAHs and oPAHs varied largely in different coals, while slightly in different biomasses. Furthermore, the nPAHs and oPAHs composition profiles varied largely from emission source to the nearby atmosphere, implying that the composition of PAHs derivative changed during small-scale transport process. Results from this study can fill in the data gap in PAHs derivative emissions from residential solid fuel combustion and help to evaluate the environmental and health impacts of residential solid fuel combustion.

Characterising personal, household, and community PM2.5 exposure in one urban and two rural communities in China

BACKGROUND

Cooking and heating in households contribute importantly to air pollution exposure worldwide. However, there is insufficient investigation of measured fine particulate matter (PM2.5) exposure levels, variability, seasonality, and inter-spatial dynamics associated with these behaviours.

METHODS

We undertook parallel measurements of personal, household (kitchen and living room), and community PM2.5 in summer (May-September 2017) and winter (November 2017-Janauary 2018) in 477 participants from one urban and two rural communities in China. After stringent data cleaning, there were 67,326-80,980 person-hours (ntotal = 441; nsummer = 384; nwinter = 364; 307 had repeated PM2.5 data in both seasons) of processed data per microenvironment. Age- and sex-adjusted geometric means of PM2.5 were calculated by key participant characteristics, overall and by season. Spearman correlation coefficients between PM2.5 levels across different microenvironments were computed.

FINDINGS

Overall, 26.4 % reported use of solid fuel for both cooking and heating. Solid fuel users had 92 % higher personal and kitchen 24-h average PM2.5 exposure than clean fuel users. Similarly, they also had a greater increase (83 % vs 26 %) in personal and household PM2.5 from summer to winter, whereas community levels of PM2.5 were 2-4 times higher in winter across different fuel categories. Compared with clean fuel users, solid fuel users had markedly higher weighted annual average PM2.5 exposure at personal (78.2 [95 % CI 71.6-85.3] μg/m3 vs 41.6 [37.3-46.5] μg/m3), kitchen (102.4 [90.4-116.0] μg/m3 vs 52.3 [44.8-61.2] μg/m3) and living room (62.1 [57.3-67.3] μg/m3 vs 41.0 [37.1-45.3] μg/m3) microenvironments. There was a remarkable diurnal variability in PM2.5 exposure among the participants, with 5-min moving average from 10 μg/m3 to 700-1200 μg/m3 across different microenvironments. Personal PM2.5 was moderately correlated with living room (Spearman r: 0.64-0.66) and kitchen (0.52-0.59) levels, but only weakly correlated with community levels, especially in summer (0.15-0.34) and among solid fuel users (0.11-0.31).

CONCLUSION

Solid fuel use for cooking and heating was associated with substantially higher personal and household PM2.5 exposure than clean fuel users. Household PM2.5 appeared a better proxy of personal exposure than community PM2.5.

A scientometric analysis of indoor air pollution research during 1990-2019

Indoor air pollution (IAP) is one of the leading risk factors for various adverse health outcomes including premature deaths globally. Even though research related to IAP has been carried out, bibliometric studies with particular emphasis on this topic have been lacking. Here, we investigated IAP research from 1990 to 2019 retrieved from the Web of Science database through a comprehensive and systematic scientometric analysis using the CiteSpace 5.7.R2, a powerful tool for visualizing structural, temporal patterns and trends of a scientific field. There was an exponential increase in publications, however, with a stark difference between developed and developing countries. The journals publishing IAP related research had multiple disciplines; 'Indoor Air' journal that focuses solely on IAP issues ranked fifth among top-cited journals. The terms like 'global burden', 'comparative risk assessment,' 'household air pollution (HAP)', 'ventilation', 'respiratory health', 'emission factor', 'impact,' 'energy', 'household', 'India' were the current topical subject where author Kirk R. Smith was identified with a significant contribution. Research related to rural, fossil-fuel toxicity, IAP, and exposure-assessment had the highest citation burst signifying the particular attention of scientific communities to these subjects. Overall, this study examined the evolution of IAP research, identified the gaps and provided future research directions.

Associations of long-term ambient air pollution and traffic-related pollution with blood pressure and hypertension defined by the different guidelines worldwide: the CHCN-BTH study

The assessment of the generalization of the strict hypertension definition in the 2017 ACC/AHA Hypertension Guideline from environmental condition remains sparse. The aims of this study are to investigate and compare the associations of ambient air pollution and traffic-related pollution (TRP) with hypertension defined by the different criteria. A total of 32,135 participants were recruited from the baseline survey of the CHCN-BTH in 2017. We defined hypertension as SBP/DBP ≥ 140/90 mmHg according to the hypertension guidelines in China, Japan, Europe and ISH (traditional criteria) and defined as SBP/DBP ≥ 130/80 mmHg according to the 2017 ACC/AHA Hypertension Guideline (strict criteria). A two-level generalized linear mixed models were applied to investigate the associations of air pollutants (i.e. PM_2.5, SO₂, NO₂) and TRP with blood pressure (BP) measures and hypertension. Stratified analyses and two-pollutant models were also performed. The stronger associations of air pollutants were found in the hypertension defined by the strict criteria than that defined by the traditional criteria. The ORs per an IQR increase in PM_2.5 were 1.17 (95% CI: 1.09, 1.25) for the strict criteria and 1.14 (95% CI: 1.06, 1.23) for the traditional criteria. The similar conditions were also observed for TRP. The above results were robust in both stratified analyses and two-pollutant models. Our study assessed the significance of the hypertension defined by the strict criteria from environmental aspect and called attention to the more adverse effects of air pollution and TRP on the earlier stage of hypertension.

Secular trends in global burden of diabetes attributable to particulate matter pollution from 1990 to 2019

Increasing evidence suggests an association between fine particulate matter (PM2.5) exposure and type 2 diabetes mellitus. However, there is still a lack of comparative evaluation regarding diabetes burden due to ambient and indoor PM2.5 pollution at a global scale. This study attempts to provide a systematic and comprehensive profile for PM2.5-attributable burden of diabetes and its spatiotemporal trends, globally and regionally. Comparative estimates of diabetes attributable to ambient PM2.5 and household air pollution (HAP) from solid fuels for 204 countries and territories were derived from the Global Burden of Disease Study 2019. Globally, 292.5 (95% uncertainty interval: 207.1, 373.4) thousand deaths and 13.0 (9.1, 17.2) million disability-adjusted life years (DALYs) from diabetes were attributed to PM2.5 pollution in 2019, wherein more than two-thirds (67.3% deaths and 69.7% DALYs) were contributed by ambient PM2.5. Compared to 1990, age-standardized DALY rate (ASDR) in 2019 attributable to ambient PM2.5 increased by 85.9% (APC: 2.21% [2.15, 2.27]), while HAP-associated ASDR decreased by 37.9% (APC: - 1.66% [- 1.82, - 1.50]). We observed a negative correlation between SDI and APC in ASMR (rs =  - 0.5, p < 0.001) and ASDR (rs = -0.4, p < 0.001) among 204 countries and territories. HAP-related diabetes experienced a sharp decline during 1990-2019, while global burden of diabetes attributable to ambient PM2.5 was rising rapidly. The elderly and people in low-SDI countries suffered from the greatest burden of diabetes due to PM2.5 pollution. More targeted interventions should be taken by governments to reduce PM2.5 exposure and related diabetes burden.

Visualization and analysis of mapping knowledge domains for the global transition towards clean cooking: a bibliometric review of research output from 1990 to 2020

Current statistics report that 2.6 billion households across the globe rely on polluting and inefficient cooking fuels and technologies, posing death-threatening health risks to people mainly from developing countries/regions. Several studies on clean cooking have been conducted with the emergence of international organizations such as the Clean Cooking Alliance to raise awareness. In the current study, a bibliometric tool, CiteSpace, was employed to analyze the 877 documents retrieved from the SCI-EXPANDED, SSCI, and A&HCI databases on clean cooking research from 1990 to 2020. The results reveal that interest in clean cooking research took a sharp rise in the last decade, especially after 2016. The research field has become increasingly interdisciplinary but has mostly centered on environment, energy, and health. The most productive countries/regions in this field are the USA, India, England, and China. The keyword and citation analyses indicate that research in this field mostly focuses on adverse impacts of household air pollution from unclean cooking fuels and technologies on the environment and public health particularly, in developing countries/regions. Also, the drivers and barriers to the large-scale adoption of clean cooking fuels and technologies have become a topic of interest in recent years. The three most studied clean cooking fuels among various regions are LPG, biogas, and electricity. This study synthesizes global research on clean cooking and may be beneficial to other researchers in understanding current trends in this field and serve as a guide for concentrating on the most important topics.

Long-term evaluation of a low-cost air sensor network for monitoring indoor and outdoor air quality at the community scale

Given the growing interest in community air quality monitoring using low-cost sensors, 30 PurpleAir II sensors (12 outdoor and 18 indoor) were deployed in partnership with community members living adjacent to a major interstate freeway from December 2017- June 2019. Established quality assurance/quality control techniques for data processing were used and sensor data quality was evaluated by calculating data completeness and summarizing PM_2.5 measurements. To evaluate outdoor sensor performance, correlation coefficients (r) and coefficients of divergence (CoD) were used to assess temporal and spatial variability of PM_2.5 between sensors. PM_2.5 concentrations were also compared to traffic levels to assess the sensors' ability to detect traffic pollution. To evaluate indoor sensors, indoor/outdoor (I/O) ratios during resident-reported activities were calculated and compared, and a linear mixed-effects regression model was developed to quantify the impacts of ambient air quality, microclimatic factors, and indoor human activities on indoor PM_2.5. In general, indoor sensors performed more reliably than outdoor sensors (completeness: 73% versus 54%). All outdoor sensors were highly temporally correlated (r > 0.98) and spatially homogeneous (CoD<0.06). The observed I/O ratios were consistent with existing literature, and the mixed-effects model explains >85% of the variation in indoor PM_2.5 levels, indicating that indoor sensors detected PM_2.5 from various sources. Overall, this study finds that community-maintained sensors can effectively monitor PM_2.5, with main data quality concerns resulting from outdoor sensor data incompleteness.

LPG stove and fuel intervention among pregnant women reduce fine particle air pollution exposures in three countries: Pilot results from the HAPIN trial

The Household Air Pollution Intervention Network trial is a multi-country study on the effects of a liquefied petroleum gas (LPG) stove and fuel distribution intervention on women's and children's health. There is limited data on exposure reductions achieved by switching from solid to clean cooking fuels in rural settings across multiple countries. As formative research in 2017, we recruited pregnant women and characterized the impact of the intervention on personal exposures and kitchen levels of fine particulate matter (PM2.5) in Guatemala, India, and Rwanda. Forty pregnant women were enrolled in each site. We measured cooking area concentrations of and personal exposures to PM2.5 for 24 or 48 h using gravimetric-based PM2.5 samplers at baseline and two follow-ups over two months after delivery of an LPG cookstove and free fuel supply. Mixed models were used to estimate PM2.5 reductions. Median kitchen PM2.5 concentrations were 296 μg/m3 at baseline (interquartile range, IQR: 158-507), 24 μg/m3 at first follow-up (IQR: 18-37), and 23 μg/m3 at second follow-up (IQR: 14-37). Median personal exposures to PM2.5 were 134 μg/m3 at baseline (IQR: 71-224), 35 μg/m3 at first follow-up (IQR: 23-51), and 32 μg/m3 at second follow-up (IQR: 23-47). Overall, the LPG intervention was associated with a 92% (95% confidence interval (CI): 90-94%) reduction in kitchen PM2.5 concentrations and a 74% (95% CI: 70-79%) reduction in personal PM2.5 exposures. Results were similar for each site. CONCLUSIONS: The intervention was associated with substantial reductions in kitchen and personal PM2.5 overall and in all sites. Results suggest LPG interventions in these rural settings may lower exposures to the WHO annual interim target-1 of 35 μg/m3. The range of exposure contrasts falls on steep sections of estimated exposure-response curves for birthweight, blood pressure, and acute lower respiratory infections, implying potentially important health benefits when transitioning from solid fuels to LPG.

Air quality changes in cities during the COVID-19 lockdown: A critical review

In response to the rapid spread of coronavirus disease-2019 (COVID-19) within and across countries and the need to protect public health, governments worldwide introduced unprecedented measures such as restricted road and air travel and reduced human mobility in 2020. The curtailment of personal travel and economic activity provided a unique opportunity for researchers to assess the interplay between anthropogenic emissions of primary air pollutants, their physical transport, chemical transformation, ultimate fate and potential health impacts. In general, reductions in the atmospheric levels of outdoor air pollutants such as particulate matter (PM), nitrogen dioxide (NO2), carbon monoxide (CO), sulfur dioxide (SO2), and volatile organic compounds (VOCs) were observed in many countries during the lockdowns. However, the levels of ozone (O3), a secondary air pollutant linked to asthma and respiratory ailments, and secondary PM were frequently reported to remain unchanged or even increase. An increase in O3 can enhance the formation of secondary PM2.5, especially secondary organic aerosols, through the atmospheric oxidation of VOCs. Given that the gaseous precursors of O3 (VOCs and NOx) are also involved in the formation of secondary PM2.5, an integrated control strategy should focus on reducing the emission of the common precursors for the co-mitigation of PM2.5 and O3 with an emphasis on their complex photochemical interactions. Compared to outdoor air quality, comprehensive investigations of indoor air quality (IAQ) are relatively sparse. People spend more than 80% of their time indoors with exposure to air pollutants of both outdoor and indoor origins. Consequently, an integrated assessment of exposure to air pollutants in both outdoor and indoor microenvironments is needed for effective urban air quality management and for mitigation of health risk. To provide further insights into air quality, we do a critical review of scientific articles, published from January 2020 to December 2020 across the globe. Finally, we discuss policy implications of our review in the context of global air quality improvement.

Personal exposure to PM2.5 of indoor and outdoor origin in two neighboring Chinese communities with contrasting household fuel use patterns

The Chinese government is replacing high-polluting, household coal heating stoves with electricity- and natural gas-powered heaters to improve ambient air quality. The evaluation of the intervention impact on outdoor PM_2.5 and personal exposure in community level are in their initial stages. We compared outdoor air pollution and personal exposure in two neighboring communities (~2 km) in northern China with contrasting household fuel use patterns: one where residents primarily used coal for cooking and heating ("coal village") and one where natural gas was the dominant fuel ("gas village"). We collected 24-h outdoor gravimetric PM_2.5 samples in each village and concurrently measured 48-h integrated exposures among 71 participants from 41 and 30 households in the coal and gas villages, respectively. PM_2.5 samples were analyzed for mass and chemical composition. Daily outdoor PM_2.5 concentrations in the coal village (mean ± standard deviation: 109 ± 41 μg/m³) were, on average, 1.3 ± 0.2 times higher than in the gas village (88 ± 38 μg/m³). However, personal PM_2.5 exposures were lower in the coal village (116 ± 121 μg/m³ versus 156 ± 106 μg/m³). PM_2.5 species that can serve as tracers for residential coal combustion (e.g., S, Se, Zn, Pb, etc.) and dust (Al, Ca, Mg, Fe, Si and Ti) were higher in the coal village, and the proportion of personal PM_2.5 of outdoor origin in the coal village was nearly 2 times higher than the gas village. Our results suggest that ambient PM_2.5 and its chemical composition can vary at relatively small spatial scales and may reflect community-level differences in the household energy use. However, personal PM_2.5 exposures may not mirror between-village differences in outdoor air pollution if only PM_2.5 mass is evaluated. Individual chemical composition of PM_2.5 exposure can provide important insight in future studies on the effectiveness of source-targeted air quality interventions.

Chemical Investigation of Household Solid Fuel Use and Outdoor Air Pollution Contributions to Personal PM2.5 Exposures

In communities with household solid fuel use, transitioning to clean stoves/fuels often results in only moderate reductions in fine particulate matter (PM2.5) exposures; the chemical composition of those exposures may help explain why. We collected personal exposure (men and women) and outdoor PM2.5 samples in villages in three Chinese provinces (Shanxi, Beijing, and Guangxi) and measured chemical components, including water-soluble organic carbon (WSOC), ions, elements, and organic tracers. Source contributions from chemical mass balance modeling (biomass burning, coal combustion, vehicles, dust, and secondary inorganic aerosol) were similar between outdoor and personal PM2.5 samples. Principal component analysis of organic and inorganic components identified analogous sources, including a regional ambient source. Chemical components of PM2.5 exposures did not differ significantly by gender. Participants using coal had higher personal/outdoor (P/O) ratios of coal combustion tracers (picene, sulfate, As, and Pb) than those not using coal, but no such trend was observed for biomass burning tracers (levoglucosan, K+, WSOC). Picene and most levoglucosan P/O ratios exceeded 1 even among participants not using coal and biomass, respectively, indicating substantial indirect exposure to solid fuel emissions from other homes. Contributions of community-level emissions to exposures suggest that meaningful exposure reductions will likely require extensive fuel use changes within communities.

Housing Quality in a Rural and an Urban Settlement in South Africa

During 2016 to 2018, a prospective household cohort study of influenza and respiratory syncytial virus community burden and transmission dynamics (the PHIRST study) was undertaken to examine the factors associated with influenza and other respiratory pathogen transmissions in South Africa. We collected information on housing conditions in the PHIRST study sites: Rural villages near Agincourt, Bushbuckridge Municipality, Mpumalanga Province, and urban Jouberton Township in North West Province. Survey data were collected from 159 and 167 study households in Agincourt and Jouberton, respectively. Multiple housing-related health hazards were identified in both sites, but particularly in Agincourt. In Agincourt, 75% (119/159) of households reported daily or weekly interruptions in water supply and 98% (154/159) stored drinking water in miscellaneous containers, compared to 1% (1/167) and 69% (115/167) of households in Jouberton. Fuels other than electricity (such as wood) were mainly used for cooking by 44% (70/159) and 7% (11/167) of Agincourt and Jouberton households, respectively; and 67% (106/159) of homes in Agincourt versus 47% (79/167) in Jouberton were located on unpaved roads, which is associated with the generation of dust and particulate matter. This study has highlighted housing conditions in Agincourt and Jouberton that are detrimental to health, and which may impact disease severity or transmission in South African communities.

Regional and seasonal variations in household and personal exposures to air pollution in one urban and two rural Chinese communities: A pilot study to collect time-resolved data using static and wearable devices

BACKGROUND

Previous studies of the health impact of ambient and household air pollution (AAP/HAP) have chiefly relied on self-reported and/or address-based exposure modelling data. We assessed the feasibility of collecting and integrating detailed personal exposure data in different settings and seasons.

METHODS/DESIGN

We recruited 477 participants (mean age 58 years, 72% women) from three (two rural [Gansu/Henan] and one urban [Suzhou]) study areas in the China Kadoorie Biobank, based on their previously reported fuel use patterns. A time-resolved monitor (PATS+CO) was used to measure continuously for 120-hour the concentration of fine particulate matter (PM2.5) at personal and household (kitchen and living room) levels in warm (May-September 2017) and cool (November 2017-January 2018) seasons, along with questionnaires on participants' characteristics (e.g. socio-demographic, and fuel use) and time-activity (48-hour). Parallel local ambient monitoring of particulate matter (PM1, PM2.5 and PM10) and gaseous pollutants (CO, ozone, nitrogen oxides) was conducted using regularly-calibrated devices. The air pollution exposure data were compared by study sites and seasons.

FINDINGS

Overall 76% reported cooking at least weekly (regular-cooks), and 48% (urban 1%, rural 65%) used solid fuels (wood/coal) for cooking. Winter heating was more common in rural sites than in urban site (74-91% vs 17% daily), and mainly involved solid fuels. Mixed use of clean and solid fuels was common for cooking in rural areas (38%) but not for heating (0%). Overall, the measured mean PM2.5 levels were 2-3 fold higher in the cool than warm season, and in rural (e.g. kitchen: Gansuwarm_season = 142.3 µg/m3; Gansucool_season = 508.1 µg/m3; Henanwarm_season = 77.5 µg/m3; Henancool_season = 222.3 µg/m3) than urban sites (Suzhouwarm_season = 41.6 µg/m3; Suzhoucool_season = 81.6 µg/m3). The levels recorded tended to be the highest in kitchens, followed by personal, living room and outdoor. Time-resolved data show prominent peaks consistently recorded in the kitchen at typical cooking times, and sustained elevated PM2.5 levels (> 100 µg/m3) were observed in rural areas where use of solid fuels for heating was common.

DISCUSSION

Personal air pollution exposure can be readily assessed using a low-cost time-resolved monitor in different settings, which, in combination with other personal and health outcome data, will enable reliable assessment of the long-term health effects of HAP/AAP exposures in general populations.

Air pollution and cause-specific mortality: A comparative study of urban and rural areas in China

Air pollution increases the risks of all-cause mortality, cardiovascular mortality and respiratory mortality across China. However, the urban-rural differences in the associations between air pollution and mortality have not been clearly identified. In this study, a distributed lag nonlinear model was used to examine whether the air pollutants-mortality associations vary between urban and rural areas. Then, we used logistic regression analyses to evaluate the air pollutants-mortality relations. Also, generalized additive models were simulated to evaluate the nonlinear curves. Our results showed that the relative risks of air pollution-related mortality were generally higher in rural areas, where PM_2.5 pollution was the dominant factor (p-value < 0.05). Mortality risks for all-cause, cardiovascular and respiratory will increase when average annual PM_2.5 concentrations exceed approximately 38 μg/m³, 41 μg/m³ and 41 μg/m³, respectively, all of which exceed the annual Grade II standards. In urban areas, PM_10-2.5 and NO₂ were associated with mortality (p-value < 0.05). We proposed some area-specific strategies for controlling the NO₂ pollution and PM_10-2.5 pollution in urban areas and the PM_2.5 pollution in rural areas to eliminate the gaps. Our findings identify that rural residents are more sensitive to air pollution than urban residents in China, and this result challenges previous assumptions about the more adverse effects of urbanization on residents' health in developing countries.

Systems Science Approaches for Global Environmental Health Research: Enhancing Intervention Design and Implementation for Household Air Pollution (HAP) and Water, Sanitation, and Hygiene (WASH) Programs

BACKGROUND

Two of the most important causes of global disease fall in the realm of environmental health: household air pollution (HAP) and poor water, sanitation, and hygiene (WASH) conditions. Interventions, such as clean cookstoves, household water treatment, and improved sanitation facilities, have great potential to yield reductions in disease burden. However, in recent trials and implementation efforts, interventions to improve HAP and WASH conditions have shown few of the desired health gains, raising fundamental questions about current approaches.

OBJECTIVES

We describe how the failure to consider the complex systems that characterize diverse real-world conditions may doom promising new approaches prematurely. We provide examples of the application of systems approaches, including system dynamics, network analysis, and agent-based modeling, to the global environmental health priorities of HAP and WASH research and programs. Finally, we offer suggestions on how to approach systems science.

METHODS

Systems science applied to environmental health can address major challenges by a) enhancing understanding of existing system structures and behaviors that accelerate or impede aims; b) developing understanding and agreement on a problem among stakeholders; and c) guiding intervention and policy formulation. When employed in participatory processes that engage study populations, policy makers, and implementers, systems science helps ensure that research is responsive to local priorities and reflect real-world conditions. Systems approaches also help interpret unexpected outcomes by revealing emergent properties of the system due to interactions among variables, yielding complex behaviors and sometimes counterintuitive results.

DISCUSSION

Systems science offers powerful and underused tools to accelerate our ability to identify barriers and facilitators to success in environmental health interventions. This approach is especially useful in the context of implementation research because it explicitly accounts for the interaction of processes occurring at multiple scales, across social and environmental dimensions, with a particular emphasis on linkages and feedback among these processes. https://doi.org/10.1289/EHP7010.

Household air pollution from cooking and heating and its impacts on blood pressure in residents living in rural cave dwellings in Loess Plateau of China

Cave dwelling is an ancient and unique type of residence in the Loess Plateau of Northern China, where the economics are less-developed. The majority of the local dwellers rely on traditional solid fuels for cooking and heating, which can emit large amounts of particles into both indoor and outdoor environments. In this study, we measured the real-time household concentrations of PM_2.5 and explored the association between personal daily PM_2.5 exposure and blood pressure (BP). Cooking and heating activities with different energies made a great variation in the household PM_2.5 air pollution, and residents using biomass had the highest personal PM_2.5 exposure. Temperature and relative humidity are both significantly linear correlated with household PM_2.5 air pollution. Besides, systolic blood pressure (SBP) was demonstrated to be positively associated with personal PM_2.5 exposure: with each 10-μg/m³ incremental PM_2.5 concentration when controlling all the other factors, SBP will increase by 0.36 mmHg (95% confident interval (CI) 0.05-0.0.77 mmHg). If solid fuels could be replaced with clean energies, personal PM_2.5 exposure and SBP would reduce by more than 21% and 3.7%, respectively, calling for efficient intervention programs to mitigate household air pollution of cave dwellings and protect health of those residents.

Associations of socioeconomic factors with cause-specific Mortality and burden of cardiovascular diseases: findings from the vital registration in urban Shanghai, China, during 1974-2015

Background

Cardiovascular disease (CVD) is the leading cause of mortality worldwide. The effect of socioeconomic factors on cause-specific mortality and burden of CVD is rarely evaluated in low- and middle-income countries, especially in a rapidly changing society.

Methods

Original data were derived from the vital registration system in Yangpu, a representative, population-stable district of urban Shanghai, China, during 1974–2015. Temporal trends for the mortality rates and burden of CVD during 1974–2015 were evaluated using Joinpoint Regression Software. The burden was evaluated using age-standardized person years of life loss per 100,000 persons (SPYLLs). Age-sex-specific CVD mortality rates were predicted by using age-period-cohort Poisson regression model.

Results

A total of 101,822 CVD death occurred during 1974–2015, accounting for 36.95% of total death. Hemorrhagic stroke, ischemic heart disease, and ischemic stroke were the 3 leading causes of CVD death. The age-standardized CVD mortality decreased from 144.5/100,000 to 100.7/100,000 in the residents (average annual percentage change [AAPC] -1.0, 95% confidence interval [CI] -1.7 to − 0.2), which was mainly contributed by women (AAPC -1.3, 95% CI − 2.0 to − 0.7), not by men. Hemorrhagic stroke, the major CVD death in the mid-aged population, decreased dramatically after 1991. The crude mortality of ischemic heart disease kept increasing but its age-adjusted mortality decreased continually after 1997. SPYLLs of CVD death increased from 1974 to 1986 (AAPC 2.1, 95% CI 0.4 to 3.8) and decreased after 1986 (AAPC 1.8, 95% CI − 2.3 to − 1.3). These changes were in concert with the implementation of policies including extended medical insurance coverage, pollution control, active prophylaxis of CVD including lifestyle promotion, and national health programs. The mortality of CVD increased in those born during 1937–1945, a period of the Japanese military occupation, and during 1958–1965, a period including the Chinese Famine. Sequelae of CVD and ischemic heart disease are predicted to be the leading causes of CVD death in 2029.

Conclusions

Exposure to serious malnutrition in early life might increase CVD mortality in later life. Improvements in medical services, pollution control, and lifestyle could decrease CVD death. New strategy is needed to prevent the aging-related CVD death and burden in the future.

The Association of Cooking Fuel Use, Dietary Intake, and Blood Pressure among Rural Women in China

Household air pollution (HAP) from solid cooking fuels continues to affect 600 million people in China and has been associated with high blood pressure. The role of diet in HAP-associated high blood pressure has yet to be evaluated in China. The aim of this study was to estimate the impact of cooking fuel on change in blood pressure and evaluate whether intake of antioxidant- and omega-3 fatty acid-rich foods (fruits, vegetables, and seafood) attenuates any adverse effects of solid fuel use on blood pressure. We analyzed longitudinal data collected between 1991 and 2011 from nonpregnant women aged 18 to 80 years living in rural areas of China. We used linear mixed effects models to estimate the association between cooking fuel (coal or wood versus clean [electric or liquid petroleum gas]) and blood pressure. Possible mediation of the fuel effect by diet was assessed by the difference method. A total of 6671 women were included in this study. Women less than 40 years of age cooking with cleaner fuels over time had lower rates of change in systolic blood pressure compared to women cooking with coal (p = 0.004), and this effect was not mediated by dietary intake. Associations between fuel use and change in diastolic blood pressure were not significant. These findings lend further support for there being a direct effect of reducing HAP on improvements in blood pressure, independent of concurrent dietary intake.

Comparing regional stove-usage patterns and using those patterns to model indoor air quality impacts

Monitoring improved cookstove adoption and usage in developing countries can help anticipate potential health and environmental benefits that may result from household energy interventions. This study explores stove-usage monitor (SUM)-derived usage data from field studies in China (52 stoves, 1422 monitoring days), Honduras (270 stoves, 630 monitoring days), India (19 stoves, 565 monitoring days), and Uganda (38 stoves, 1007 monitoring days). Traditional stove usage was found to be generally similar among four seemingly disparate countries in terms of cooking habits, with average usage of between 171 and 257 minutes per day for the most-used stoves. In Honduras, where survey-based usage data were also collected, there was only modest agreement between sensor data and self-reported user data. For Indian homes, we combined stove-usage data with a single-zone Monte Carlo box model to estimate kitchen-level PM_2.5 and CO concentrations under various scenarios of cleaner cookstove adoption. We defined clean cookstove performance based on the International Standards Organization (ISO) voluntary guidelines. Model results showed that even with 75% displacement of traditional stoves with the cleanest available stove (ISO tier-5), World Health Organization 24 hours PM_2.5 standards were exceeded in 96.4% of model runs, underscoring the importance of full displacement.

Air pollutant emission factors of solid fuel stoves and estimated emission amounts in rural Beijing

Solid fuels used for heating and cooking in rural households cause a large amount of pollutant emissions. Actions are being taken to replace these solid fuels with cleaner energy carriers. However, the pollutant emission amounts from solid fuels over large areas have rarely been evaluated. In this study, we tested eight common heating stoves consuming bituminous coal chunk, anthracite coal chunk, and anthracite coal briquette; three honeycomb briquette stoves; and three traditional cookstoves consuming corn straw and wood in rural Beijing. Emission factors of particulate matter with aerodynamic diameters ≤2.5 μm (PM_2.5), carbon monoxide (CO), nitrogen oxide (NO_x), and sulfur dioxide (SO₂), were measured as 0.08-13.74 g/kg, 10.80-148.5 g/kg, 0.52-8.44 g/kg, and 0-0.85 g/kg, respectively, for coal heating stoves; 0.35-1.11 g/kg, 16.10-109.43 g/kg, 0.51-0.75 g/kg, and 0-1.98 g/kg, respectively, for honeycomb briquette cookstoves; and 5.90-11.79 g/kg, 28.96-50.23 g/kg, 1.52-2.46 g/kg, and 0-0.05 g/kg, respectively, for traditional biomass cookstoves. Combining emission performance and solid fuel consumption, the estimated annual PM_2.5, CO, NO_x, and SO₂ emission amounts were 26.18 Gg, 394.07 Gg, 14.56 Gg, and 1.53 Gg, respectively. The results present useful information regarding the emission inventory of common solid fuels in rural Beijing on a city-scale. This study provides an example for future intervention projects and environment evaluation in the rural areas of other cities.

Impacts of stove/fuel use and outdoor air pollution on chemical composition of household particulate matter

Biomass combustion for cooking and heating releases particulate matter (PM_2.5 ) that contributes to household air pollution. Fuel and stove types affect the chemical composition of household PM, as does infiltration of outdoor PM. Characterization of these impacts can inform future exposure assessments and epidemiologic studies, but is currently limited. In this study, we measured chemical components of PM_2.5 (water-soluble organic matter [WSOM], ions, black carbon, elements, organic tracers) in rural Chinese households using traditional biomass stoves, semi-gasifier stoves with pelletized biomass, and/or non-biomass stoves. We distinguished households using one stove type (traditional, semi-gasifier, or LPG/electric) from those using multiple stoves/fuels. WSOM concentrations were higher in households using only semi-gasifier or traditional stoves (31%-33%) than in those with exclusive LPG/electric stove (13%) or mixed stove use (12%-22%). Inorganic ions comprised 14% of PM in exclusive LPG/electric households, compared to 1%-5% of PM in households using biomass. Total PAH content was much higher in households that used traditional stoves (0.8-2.8 mg/g PM) compared to those that did not (0.1-0.3 mg/g PM). Source apportionment revealed that biomass burning comprised 27%-84% of PM_2.5 in households using biomass. In all samples, identified outdoor sources (vehicles, dust, coal combustion, secondary aerosol) contributed 10%-20% of household PM_2.5 .

Adapting and Operationalizing the RE-AIM Framework for Implementation Science in Environmental Health: Clean Fuel Cooking Programs in Low Resource Countries

Introduction: The use of models and frameworks to design and evaluate strategies to improve delivery of evidence-based interventions is a foundational element of implementation science. To date, however, evaluative implementation science frameworks such as Reach, Effectiveness, Adoption, Implementation, Maintenance (RE-AIM) have not been widely employed to examine environmental health interventions. We take advantage of a unique opportunity to utilize and iteratively adapt the RE-AIM framework to guide NIH-funded case studies of the implementation of clean cooking fuel programs in eleven low- and middle-income countries. Methods: We used existing literature and expert consultation to translate and iteratively adapt the RE-AIM framework across several stages of the NIH Clean Cooking Implementation Science case study project. Checklists and templates to guide investigators were developed at each stage. Results: The RE-AIM framework facilitated identification of important emerging issues across this set of case studies, in particular highlighting the fact that data associated with certain important outcomes related to health and welfare are chronically lacking in clean fuel programs. Monitoring of these outcomes should be prioritized in future implementation efforts. As RE-AIM was not originally designed to evaluate household energy interventions, employing the framework required adaptation. Specific adaptations include the broadening of Effectiveness to encompass indicators of success toward any stated programmatic goal, and expansion of Adoption to include household-level uptake of technology. Conclusions: The RE-AIM implementation science framework proved to be a useful organizing schema for 11 case studies of clean fuel cooking programs, in particular highlighting areas requiring emphasis in future research and evaluation efforts. The iterative approach used here to adapt an implementation science framework to a specific programmatic goal may be of value to other multi-country program efforts, such as those led by international development agencies. The checklists and templates developed for this project are publicly available for others to use and/or further modify.

Supply Considerations for Scaling Up Clean Cooking Fuels for Household Energy in Low- and Middle-Income Countries

Promoting access to clean household cooking energy is an important subject for policy making in low- and middle-income countries, in light of urgent and global efforts to achieve universal energy access by 2030 (Sustainable Development Goal 7). In 2014, the World Health Organization issued "Guidelines for Indoor Air Quality: Household Fuel Combustion", which recommended a shift to cleaner fuels rather than promotion of technologies that more efficiently combust solid fuels. This study fills an important gap in the literature on transitions to household use of clean cooking energy by reviewing supply chain considerations for clean fuel options in low- and middle-income countries. For the purpose of this study, we consider electricity, liquefied petroleum gas (LPG), alcohol fuels, biogas, and compressed biomass pellets burned in high performing gasifier stoves to be clean fuel options. Each of the clean fuels reviewed in this study, as well as the supply of electricity, presents both constraints and opportunities for enhanced production, supply, delivery, and long-term sustainability and scalability in resource-poor settings. These options are reviewed and discussed together with policy and regulatory considerations to help in making these fuel and energy choices available and affordable. Our hope is that researchers, government officials and policy makers, and development agencies and investors will be aided by our comparative analysis of these clean household energy choices.

Household Transitions to Clean Energy in a Multi-Provincial Cohort Study in China

Household solid fuel (biomass, coal) burning contributes to climate change and is a leading health risk factor. How and why households stop using solid fuel stoves after adopting clean fuels has not been studied. We assessed trends in the uptake, use, and suspension of household stoves and fuels in a multi-provincial cohort study of 753 Chinese adults and evaluated determinants of clean fuel uptake and solid fuel suspension. Over one-third (35%) and one-fifth (17%) of participants suspended use of solid fuel for cooking and heating, respectively, during the past 20 years. Determinants of solid fuel suspension (younger age, widowed) and of earlier suspension (younger age, higher education, and poor self-reported health status) differed from the determinants of clean fuel uptake (younger age, higher income, smaller households, and retired) and of earlier adoption (higher income). Clean fuel adoption and solid fuel suspension warrant joint consideration as indicators of household energy transition. Household energy research and planning efforts that more closely examine solid fuel suspension may accelerate household energy transitions that benefit climate and human health.

Longitudinal evaluation of a household energy package on blood pressure, central hemodynamics, and arterial stiffness in China

BACKGROUND

Cardiovascular diseases are the leading contributors to disease burden in China and globally, and household air pollution exposure is associated with risk of cardiovascular disease.

OBJECTIVES

We evaluated whether subclinical cardiovascular outcomes in adult Chinese women would improve after distribution of an energy package comprised of a semi-gasifier cookstove, water heater, chimney, and supply of processed biomass fuel.

METHODS

We enrolled 204 households (n = 205 women) from 12 villages into a controlled before- and after-intervention study on cardiovascular health and air pollution in Sichuan Province. The intervention was distributed to 124 households during a government-sponsored rural energy demonstration program. The remaining 80 households received the package 18 months later at the end of the study, forming a comparison group. One woman from each household had their blood pressure (BP), central hemodynamics, and arterial stiffness measured along with exposures to air pollution and demographic and household characteristics, on up to five visits. We used a difference-in-differences mixed-effects regression approach with Bayesian inference to assess the impact of the energy package on sub-clinical cardiovascular outcomes.

RESULTS

Women who did not receive the energy package had greater mean decreases in brachial systolic (-4.1 mmHg, 95% credible interval (95%CIe) -7.3, -0.9) and diastolic BP (-2.0 mmHg, 95%CIe -3.6, -0.5) compared with women who received the package (systolic: -2.7, 95%CIe -5.0, -0.4; diastolic: -0.3, 95%CIe -1.4, 0.8) resulting in slightly positive but not statistically significant difference-in-differences effect estimates of 1.3 mmHg (95%CIe -2.5, 5.2) and 1.7 mmHg (95%CIe -0.3, 3.6), respectively. Similar trends were found for central BP, central pulse pressure, and arterial stiffness. Air pollution exposures decreased on average for both treatment groups, with a greater range of reductions among women who did not receive the package (with package: -30% to -50%; without package: +2% to -69%), likely as a result of increased use of gas fuel and electric stoves among this group. Outdoor air quality changed very little over time.

CONCLUSIONS

Gasifier stoves have been widely promoted as the next generation of 'clean-cooking' technologies, however their effectiveness in improving health in real-world settings should be carefully evaluated and communicated before scaling up their implementation.

Effectiveness of a Household Energy Package in Improving Indoor Air Quality and Reducing Personal Exposures in Rural China

We evaluated whether an energy package comprising a low-polluting semigasifier cookstove with chimney, water heater, and pelletized biomass fuel would improve air pollution in China. We measured the stove use, 48-h air pollution exposures (PM_2.5, black carbon), and kitchen concentrations (PM_2.5, black carbon, carbon monoxide, nitrogen oxides) for 205 women, along with ambient PM_2.5. Over half (n = 125) were offered the energy package after baseline assessment, forming "treated" and "untreated" groups, and we repeated the measurements up to 3 occasions over 18-months. Kitchen carbon monoxide did not change, and nitrogen oxides increased in summer but decreased in winter for both groups. Summer geometric mean exposures and kitchen concentrations of PM_2.5 and black carbon decreased by 24-67% in women who received the energy package, but greater reductions (48-70%) were observed in untreated homes, likely due to increased use of gas stoves. After adjusting for differences in outdoor PM_2.5, receiving the energy package was associated with decreased winter exposures to PM_2.5 (-46%; 95% CI: -70, -2) and black carbon (-55%; -74, -25) and the summer increases were smaller (PM_2.5: 8%; -22, 51 and black carbon: 37%; -12, 113). However, PM_2.5 exposures remained 1.5-3 times higher than those of health-based international air pollution targets.

Exposure–Response Associations of Household Air Pollution and Buccal Cell Telomere Length in Women Using Biomass Stoves

BACKGROUND

Telomere shortening is associated with early mortality and chronic disease. Recent studies indicate that environmental exposures, including urban and traffic-related air pollution, may shorten telomeres. Associations between exposure to household air pollution from solid fuel stoves and telomere length have not been evaluated.

METHODS

Among 137 rural Chinese women using biomass stoves ([Formula: see text] of age), we measured 48-h personal exposures to fine particulate matter [PM [Formula: see text] in aerodynamic diameter ([Formula: see text])] and black carbon and collected oral DNA on up to three occasions over a period of 2.5 y. Relative telomere length (RTL) was quantified using a modified real-time polymerase chain reaction protocol. Mixed effects regression models were used to investigate the exposure–response associations between household air pollution and RTL, adjusting for key sociodemographic, behavioral, and environmental covariates.

RESULTS

Women's daily exposures to air pollution ranged from [Formula: see text] for [Formula: see text] ([Formula: see text]) and [Formula: see text] for black carbon ([Formula: see text]). Natural cubic spline models indicated a mostly linear association between increased exposure to air pollution and shorter RTL, except at very high concentrations where there were few observations. We thus modeled the linear associations with all observations, excluding the highest 3% and 5% of exposures. In covariate-adjusted models, an interquartile range (IQR) increase in exposure to black carbon ([Formula: see text]) was associated with shorter RTL [all observations: [Formula: see text] (95% CI: [Formula: see text], [Formula: see text]); excluding highest 5% exposures: [Formula: see text] (95% CI: [Formula: see text], [Formula: see text])]. Further adjustment for outdoor temperature brought the estimates closer to zero [all observations: [Formula: see text] (95% CI: [Formula: see text], 0.06); excluding highest 5% exposures: [Formula: see text] (95% CI: [Formula: see text], [Formula: see text])]. Models with [Formula: see text] as the exposure metric followed a similar pattern.

CONCLUSION

Telomere shortening, which is a biomarker of biological aging and chronic disease, may be associated with exposure to air pollution in settings where household biomass stoves are commonly used. https://doi.org/10.1289/EHP4041.

Pellet-Fed Gasifier Stoves Approach Gas-Stove Like Performance during in-Home Use in Rwanda

Nearly all households in Rwanda burn solid fuels for cooking. A private firm in Rwanda is distributing forced-draft pellet-fed semigasifier cookstoves and fuel pellets. We measured in-use emissions of pollutants including fine particulate matter (PM_2.5), organic and elemental carbon (OC, EC), black carbon (BC), and carbon monoxide (CO) in 91 uncontrolled cooking tests (UCTs) of both pellet and baseline (wood; charcoal) stoves. We observed >90% reductions in most pollutant emission factors/rates from pellet stoves compared to baseline stoves. Pellet stoves performed far better than gasifier stoves burning unprocessed wood, and consistent with ISO tiers 4 and 5 for PM_2.5 and CO, respectively. Pellet stoves were generally clean, but performance varied; emissions from the dirtiest pellet tests matched those from the cleanest traditional stove tests. Our real-time data suggest that events occurring during ignition and the end of testing (e.g., refueling, char burnout) drive high emissions during pellet tests. We use our data to estimate potential health and climate cobenefits from stove adoption. This analysis suggests that pellet stoves have the potential to provide health benefits far above previously tested biomass stoves and approaching modern fuel stoves (e.g., LPG). Net climate impacts of pellet stoves range from similar to LPG to negligible, depending on biomass source and upstream emissions.

Chemical composition and source apportionment of ambient, household, and personal exposures to PM2.5 in communities using biomass stoves in rural China

Fine particulate matter (PM_2.5) has health effects that may depend on its sources and chemical composition. Few studies have quantified the composition of personal and area PM_2.5 in rural settings over the same time period. Yet, this information would shed important light on the sources influencing personal PM_2.5 exposures. This study investigated the sources and chemical composition of 40 personal exposure, 40 household, and 36 ambient PM_2.5 samples collected in the non-heating and heating seasons in rural southwestern China. Chemical analysis included black carbon (BC), water-soluble components (ions, organic carbon), elements, and organic tracers. Source apportionment was conducted using organic tracer concentrations in a Chemical Mass Balance model. Biomass burning was the largest identified PM_2.5 source contributor to household (average, SD: 48 ± 11%) and exposures (31 ± 6%) in both seasons, and ambient PM_2.5 in winter (20 ± 4%). Food cooking also contributed to household and personal PM, reaching approximately half of the biomass contributions. Secondary inorganic aerosol was the major identified source in summertime ambient PM_2.5 (32 ± 14%), but was present in all samples (summer: 10 ± 3% [household], 13 ± 6% [exposures]; winter: 18 ± 2% [ambient], 7 ± 2% [household], 8 ± 2% [exposures]). Dust concentrations and fractional contribution to total PM_2.5 were higher in summer exposure samples (7 ± 4%) than in ambient or household samples (6 ± 1% and 2 ± 1%, respectively). Indoor sources comprised up to one-fifth of ambient PM_2.5, and outdoor sources (vehicles, secondary aerosols) contributed up to 15% of household PM_2.5. While household sources were the main contributors to PM_2.5 exposures in terms of mass, inorganic components of personal exposures differed from household samples. Based on these findings, health-focused initiatives to reduce harmful PM_2.5 exposures may consider a coordinated approach to address both indoor and outdoor PM_2.5 source contributors.

Differences in the Nasal Inflammatory Response to Cynodon dactylon From Rural and Urban Areas in Patients With Allergic Rhinitis

Background

Epidemiological and experimental studies suggest that air pollution has a negative impact on human health and modifies the environment. However, the clinical implications of changes in environmental allergens secondary to air pollution have been little studied.

Objectives

To explore if the growth conditions of the Cynodon dactylon (rural vs urban area) modify the inflammatory response among patients with allergic rhinitis.

Methodology: Two extracts were prepared for diagnostic test with Cyn d proteins obtained from rural and urban environment. Skin prick test (SPT), nasal challenge test (NCT), and eosinophil count in nasal mucus were performed in 3 groups: healthy subjects without rhinitis, rhinitis with (+) Cyn d, and rhinitis with (−) Cyn d.

Results

There was a 97% concordance in the positive and negative results of the SPT with the 2 extracts. However, Cyn d-urban extract generated larger wheals (P = .03) and a higher number of patients with rhinitis presented a positive NCT to this extract (n = 7 vs 14, P = .04). Patients with positive NCT had a significant increase in eosinophils in mucus, but there was no difference between the extracts. The healthy controls did not react to the extracts tested in the skin or nasal test.

Conclusion

The findings suggest that the growth conditions in urban area of Cynodon dactylon can generate changes in the protein extract and have clinical implications in patients with allergic rhinitis.

Development of Renewable, Densified Biomass for Household Energy in China

Recent national strategic plans in China have set renewable energy targets for rural household energy programs, including those that advance the production of densified biomass fuels (e.g. pellets, briquettes) for use in household cooking and heating stoves. There is presently very little information on potential barriers to the successful development of densified biomass for household cooking and heating in China, but such knowledge may be informative in settings that aim to replace unprocessed coal and other polluting fuels with renewable, cleaner-burning energy sources. We designed a case study to coordinate data-gathering efforts at rural field sites in southwestern Sichuan province and northeastern Jilin and Heilongjiang provinces, where production of densified biomass fuels is under development for household end-users. We conducted interviews with factory personnel, local administrative leaders, and sector experts involved in the production and distribution of densified fuel, including pellets and briquettes, for household use. Results from our qualitative textual data analysis yielded several recommendations for improving development of densified biomass fuels for household end-use. These included reducing heterogeneity of feedstocks, increasing financial support for operational costs (e.g. collection, transport, and storage of raw materials; storage and distribution of final products), improving household perceptions of and subsequent demand for densified biomass fuels, and increasing enforcement of national and provincial policies banning the use of coal and open-field biomass burning. Collection and storage of raw materials and the final densified fuel product were consistently noted as critical challenges to scaling up production at all three sites. Finally, the perspectives of factory managers and local village administrators that we present also indicated that production of densified biomass fuels would most likely be more successful and reproducible in places where national-level policies are viewed as obligatory.

Development of Ahmedabad's Air Information and Response (AIR) Plan to Protect Public Health

Indian cities struggle with some of the highest ambient air pollution levels in the world. While national efforts are building momentum towards concerted action to reduce air pollution, individual cities are taking action on this challenge to protect communities from the many health problems caused by this harmful environmental exposure. In 2017, the city of Ahmedabad launched a regional air pollution monitoring and risk communication project, the Air Information and Response (AIR) Plan. The centerpiece of the plan is an air quality index developed by the Indian Institute of Tropical Meteorology’s System for Air Quality and Weather Forecasting and Research program that summarizes information from 10 new continuous air pollution monitoring stations in the region, each reporting data that can help people avoid harmful exposures and inform policy strategies to achieve cleaner air. This paper focuses on the motivation, development, and implementation of Ahmedabad’s AIR Plan. The project is discussed in terms of its collaborative roots, public health purpose in addressing the grave threat of air pollution (particularly to vulnerable groups), technical aspects in deploying air monitoring technology, and broader goals for the dissemination of an air quality index linked to specific health messages and suggested actions to reduce harmful exposures. The city of Ahmedabad is among the first cities in India where city leaders, state government, and civil society are proactively working together to address the country’s air pollution challenge with a focus on public health. The lessons learned from the development of the AIR Plan serve as a template for other cities aiming to address the heavy burden of air pollution on public health. Effective working relationships are vital since they form the foundation for long-term success and useful knowledge sharing beyond a single city.