Biomass fuel use and indoor air pollution in homes in Malawi

Household carbon monoxide (CO) concentrations in a large African city: An unquantified public health burden?

Carbon monoxide (CO) is a poisonous gas produced by incomplete combustion of carbon-based fuels that is linked to mortality and morbidity. Household air pollution from burning fuels on poorly ventilated stoves can lead to high concentrations of CO in homes. There are few datasets available on household concentrations of CO in urban areas of sub-Saharan African countries. CO was measured every minute over 24 h in a sample of homes in Nairobi, Kenya. Data on household characteristics were gathered by questionnaire. Metrics of exposure were summarised and analysis of temporal changes in concentration was performed. Continuous 24-h data were available from 138 homes. The mean (SD), median (IQR) and maximum 24-h CO concentration was 4.9 (6.4), 2.8 (1.0-6.3) and 44 ppm, respectively. 50% of homes had detectable CO concentrations for 847 min (14h07m) or longer during the 24-h period, and 9% of homes would have activated a CO-alarm operating to European specifications. An association between a metric of total CO exposure and self-reported exposure to vapours >15 h per week was identified, however this were not statistically significant after adjustment for the multiple comparisons performed. Mean concentrations were broadly similar in homes from a more affluent area and an informal settlement. A model of typical exposure suggests that cooking is likely to be responsible for approximately 60% of the CO exposure of Nairobi schoolchildren. Household CO concentrations are substantial in Nairobi, Kenya, despite most homes using gas or liquid fuels. Concentrations tend to be highest during the evening, probably associated with periods of cooking. Household air pollution from cooking is the main source of CO exposure of Nairobi schoolchildren. The public health impacts of long-term CO exposure in cities in sub-Saharan Africa may be considerable and should be studied further.

The Changing and Predicted Trends in Chronic Obstructive Pulmonary Disease Burden in China, the United States, and India from 1990 to 2030

Background

This study analyzed the burden of chronic obstructive pulmonary disease (COPD) in China, the United States, and India from 1990 to 2019 and projected the trends for the next decade.

Methods

This study utilized the GBD 2019 to compare the age-standardized incidence rate (ASIR), age-standardized mortality rate (ASMR), age-standardized disability-adjusted life years (DALYs) rate, and the proportion attributed to different risk factors in China, the United States, and India. Joinpoint models and autoregressive integrated moving average (ARIMA) models were employed to capture the changing trends in disease burden and forecast outcomes.

Results

From 1990 to 2019, China's age-standardized COPD incidence and mortality rates decreased by 29% and 70%, respectively. In the same period, India's rates decreased by 8% and 33%, while the United States saw an increase of 9% in COPD incidence and a 22% rise in mortality rates. Smoking and ambient particulate matter pollution are the two most significant risk factors for COPD, while household air pollution from solid fuels and low temperatures are the least impactful factors in the United States and India, respectively. The proportion of risk from household air pollution from solid fuels is higher in India than in China and the United States. Predictions for 2030 suggest that the age-standardized DALY rates, ASIR, and ASMR in the United States and India are expected to remain stable or decrease, while China's age-standardized incidence rate is projected to rise.

Conclusion

Over the past three decades, the incidence of COPD has been decreasing in China and India, while showing a slight increase in the United States. Smoking and ambient particulate matter pollution are the primary risk factors for men and women, respectively. The risk of household air pollution from solid fuels in India needs attention.

Indoor air pollution prevention practices and associated factors among household mothers in Olenchiti town, Oromia, Ethiopia

INTRODUCTION

Most households in low- and middle-income countries still cook using solid fuels in poorly ventilated dwellings. Indoor air pollution causes various health problems, like pneumonia, lung cancer, stillbirth, low birth weight, impaired cognitive development, and cataracts. Nevertheless, a few evidences are available in Africa, including Ethiopia. Therefore, this study aimed to assess the level of indoor air pollution prevention practices and associated factors among household mothers in Olenchiti town, Oromia, Ethiopia.

METHODS

A community-based cross-sectional study was conducted. Four hundred twenty mothers were randomly selected by systematic random sampling. Data was collected through an interview and observation checklist. The collected data entered into Epi-Info version 7.2.5 was cleaned, edited, and then exported to SPSS version 23 for analysis. Descriptive statistics were used to describe the findings. Binary logistic regression was computed to analyze the effect of each variable on the outcome variable. Model adequacy fitness was checked with the Hosmer-Lemeshow test. The multicollinearity of independent variables was checked with the variance inflation factor. Adjusted odds ratio with 95% confidence interval and P -value <0.05 was used as cutoff points to declare significance in the final model.

RESULTS

The overall good practices of mothers towards the prevention of indoor air pollution was 188 (45.0%). Mothers who had under-five children (AOR = 0.49, 95%CI (0.31-0.76), mothers in grade 9-12 (AOR = 0.51, 95%CI (0.28-0.92)) were significantly associated with indoor air pollution prevention practices.

CONCLUSION

The overall good practices of mothers towards indoor air pollution were low compared to different findings. Under-five children and educational status were significantly associated with indoor air pollution prevention practices in the final model. Therefore, the high school curriculums should include indoor air pollution topics.

Health risks associated with the production and usage of charcoal: a systematic review

Charcoal production and utilisation are linked to various health issues and occupational hazards. However, to our knowledge, no systematic review has primarily focused on the health implications of charcoal production and its use while distinguishing charcoal from other solid fuels such as wood and coal.

OBJECTIVES

This systematic review presents a synthesis of the evidence on the health risks associated with producing and using charcoal across the world.

DESIGN

Systematic review using a systematic narrative synthesis approach.

DATA SOURCES

MEDLINE (through Ovid interface), CINAHL, Embase, Web of Science, PsycINFO, Cochrane Library and SCOPUS, from inception to 26 February 2021.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Peer-reviewed journal articles reporting empirical findings on the associations between charcoal usage/production and health parameters.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers extracted data and assessed the quality of primary studies.

RESULTS

Our findings showed that charcoal production and usage are linked with specific adverse health outcomes, including respiratory diseases (n=21), cardiorespiratory and neurological diseases (n=1), cancer (n=3), DNA damage (n=3), carbon monoxide (CO) poisoning (n=2), physical injury (n=2), sick house syndrome (n=1), unintentional weight loss and body mass index (BMI) reduction (n=2), increase in blood pressure (n=1) and CO death (n=1). Among the included articles that reported respiratory diseases (n=21), there was one case of asthma and tuberculosis and two cases of chronic obstructive pulmonary disease.

CONCLUSIONS

This review links charcoal production/usage and some associated human health risks. These include respiratory diseases and other non-respiratory illnesses such as sick-building syndrome, cardiovascular diseases, DNA damage, CO poisoning and death, unintentional weight loss and BMI reduction, and physical injuries.

Quantifying the dynamic characteristics of indoor air pollution using real-time sensors: Current status and future implication

People generally spend most of their time indoors, making indoor air quality be of great significance to human health. Large spatiotemporal heterogeneity of indoor air pollution can be hardly captured by conventional filter-based monitoring but real-time monitoring. Real-time monitoring is conducive to change air assessment mode from static and sparse analysis to dynamic and massive analysis, and has made remarkable strides in indoor air evaluation. In this review, the state of art, strengths, challenges, and further development of real-time sensors used in indoor air evaluation are focused on. Researches using real-time sensors for indoor air evaluation have increased rapidly since 2018, and are mainly conducted in China and the USA, with the most frequently investigated air pollutants of PM_2.5. In addition to high spatiotemporal resolution, real-time sensors for indoor air evaluation have prominent advantages in 3-dimensional monitoring, pollution peak and source identification, and short-term health effect evaluation. Huge amounts of data from real-time sensors also facilitate the modeling and prediction of indoor air pollution. However, challenges still remain in extensive deployment of real-time sensors indoors, including the selection, performance, stability, as well as calibration of sensors. In future, sensors with high performance, long-term stability, low price, and low energy consumption are welcomed. Furthermore, more target air pollutants are also expected to be detected simultaneously by real-time sensors in indoor air monitoring.

Personal exposures to fine particulate matter and carbon monoxide in relation to cooking activities in rural Malawi

Background: Air pollution is a major environmental risk factor for cardiorespiratory disease. Exposures to household air pollution from cooking and other activities, are particularly high in Southern Africa. Following an extended period of participant observation in a village in Malawi, we aimed to assess individuals' exposures to fine particulate matter (PM 2.5) and carbon monoxide (CO) and to investigate the different sources of exposure, including different cooking methods. Methods: Adult residents of a village in Malawi wore personal PM 2.5 and CO monitors for 24-48 hours, sampling every 1 (CO) or 2 minutes (PM 2.5). Subsequent in-person interviews recorded potential exposure details over the time periods. We present means and interquartile ranges for overall exposures and summaries stratified by time and activity (exposure). We employed multivariate regression to further explore these characteristics, and Spearman rank correlation to examine the relationship between paired PM 2.5 and CO exposures. Results : Twenty participants (17 female; median age 40 years, IQR: 37-56) provided 831 hours of paired PM 2.5 and CO data. Concentrations of PM 2.5 during combustion activity, usually cooking, far exceeded background levels (no combustion activity): 97.9μg/m 3 (IQR: 22.9-482.0), vs 7.6μg/m 3, IQR: 2.5-20.6 respectively. Background PM 2.5 concentrations were higher during daytime hours (11.7μg/m 3 [IQR: 5.2-30.0] vs 3.3μg/m 3 at night [IQR: 0.7-8.2]). Highest exposures were influenced by cooking location but associated with charcoal use (for CO) and firewood on a three-stone fire (for PM 2.5). Cooking-related exposures were higher in more ventilated places, such as outside the household or on a walled veranda, than during indoor cooking. Conclusions : The study demonstrates the value of combining personal PM 2.5 exposure data with detailed contextual information for providing deeper insights into pollution sources and influences. The finding of similar/lower exposures during cooking in seemingly less-ventilated places should prompt a re-evaluation of proposed clean air interventions in these settings.

Personal exposures to fine particulate matter and carbon monoxide in relation to cooking activities in rural Malawi

Background: Air pollution is a major environmental risk factor for cardiorespiratory disease. Exposures to household air pollution from cooking and other activities, are particularly high in Southern Africa. Following an extended period of participant observation in a village in Malawi, we aimed to assess individuals' exposures to fine particulate matter (PM 2.5) and carbon monoxide (CO) and to investigate the different sources of exposure, including different cooking methods. Methods: Adult residents of a village in Malawi wore personal PM 2.5 and CO monitors for 24-48 hours, sampling every 1 (CO) or 2 minutes (PM 2.5). Subsequent in-person interviews recorded potential exposure details over the time periods. We present means and interquartile ranges for overall exposures and summaries stratified by time and activity (exposure). We employed multivariate regression to further explore these characteristics, and Spearman rank correlation to examine the relationship between paired PM 2.5 and CO exposures. Results : Twenty participants (17 female; median age 40 years, IQR: 37-56) provided 831 hours of paired PM 2.5 and CO data. Concentrations of PM 2.5 during combustion activity, usually cooking, far exceeded background levels (no combustion activity): 97.9μg/m 3 (IQR: 22.9-482.0), vs 7.6μg/m 3, IQR: 2.5-20.6 respectively. Background PM 2.5 concentrations were higher during daytime hours (11.7μg/m 3 [IQR: 5.2-30.0] vs 3.3μg/m 3 at night [IQR: 0.7-8.2]). Highest exposures were influenced by cooking location but associated with charcoal use (for CO) and firewood on a three-stone fire (for PM 2.5). Cooking-related exposures were higher in more ventilated places, such as outside the household or on a walled veranda, than during indoor cooking. Conclusions : The study demonstrates the value of combining personal PM 2.5 exposure data with detailed contextual information for providing deeper insights into pollution sources and influences. The finding of similar/lower exposures during cooking in seemingly less-ventilated places should prompt a re-evaluation of proposed clean air interventions in these settings.

COVID-19, the environment and animal life in Malawi compared to other countries: A brief scooping review for a research agenda in the developing countries

The impact of COVID-19 on the human population in Malawi has been documented. However, its impact on the animal population and the environment has not been thoroughly researched. Because of the well-known inter-relationship between human and animal populations and the environment, a study based on a brief scooping review of previous related studies, media and survey reports, was conducted. The findings reveal that except for a few selected studies, the research gap on COVID-19's impact on the environment and animals in Malawi is wide compared to other countries. Nonetheless, from the few identified related studies, this study has revealed that as the restriction of movement and closure of borders disrupted the supply chain of forest resources in the country, the COVID-19 pandemic has led to increased pressure on forests as a coping strategy due to significant loss of jobs in the informal sector. Although the quality of water and air improved in most parts of the globe due to reduced human activity, there is no substantial literature on the same in Malawi partly due to ineffective monitoring systems. However, COVID-19 has exposed the deficiencies in water security in Malawi, thereby creating opportunities to address them. Conversely, increased demand for water at household levels due to restricted movements contributed to environmental pollution at suburb levels. In particular, the less developed and overpopulated countries suffered from land pollution due to poor disposal of plastic generated from hospitals and personal protection equipment. Elsewhere, studies show that minimal human interference with animals outside homes resulted in an increase of fish and bird biomasses. But, unemployment rates caused by the pandemic have seriously contributed to illegal poaching in developing countries. Therefore, a rapid assessment of the impact of the pandemic on environment in Malawi, to generate the evidence needed for policy makers to use in support of the affected and also plan for the recovery and sustainability of wildlife, is recommended.

Tobacco and other risk factors for esophageal squamous cell carcinoma in Lilongwe Malawi: Results from the Lilongwe esophageal cancer case: Control study

OBJECTIVE

Esophageal cancer is the second commonest cancer in Malawi, and 95% of all cases are esophageal squamous cell carcinoma (ESCC). Very little is known about the epidemiology of ESCC in Malawi including risk factors. The main objective of the study was to evaluate and describe risk factors of ESCC in Malawi.

METHODS

We conducted a case-control study from 2017 to 2020 at two hospitals in Lilongwe, Malawi and consenting adults were eligible for inclusion. Endoscopy was conducted on all cases and biopsies were obtained for histological confirmation. Controls were selected from patients or their guardians in orthopedic, dental and ophthalmology wards and they were frequency matched by sex, age, and region of origin to cases. An electronic structured questionnaire was delivered by a trained interviewer. Multivariate conditional logistic regression models were used to assess the associations between subject characteristics, habits, and medical history and risk of ESCC.

RESULTS

During the study period, 300 cases and 300 controls were enrolled into the study. Median age of cases and controls was 56 years and 62% of the cases were male. Among cases, 30% were ever cigarette smokers as were 22% of controls. Smoking cigarettes had an adjusted odds ratio of 2.4 (95% CI 1.4-4.2 p = 0.003). HIV+ status was present in 11% of cases and 4% controls, which resulted in an adjusted odds ratio was 4.0 (95% CI 1.8-9.0 p = 0.001). Drinking hot tea was associated with an adjusted odd ratio of 2.9 (95% CI 1.3-6.3 p = 0.007). Mold on stored grain has an adjusted odd ratio of 1.6 (95% CI 1.1-2.5 p = 0.021).

CONCLUSION

Reducing smoking cigarettes, consumption of scalding hot tea, and consumption of contaminated grain, could potentially help reduce the burden of ESCC in Malawi. Further investigation of the association between HIV status and ESCC are warranted.

Assessment of household air pollution exposure of tribal women

There is a growing evidence that the burning of unprocessed biomass fuels is associated with adverse health impacts. This study estimated the gaseous pollutants (CO, CO₂, O_3, SO₂, and NO₂) and particulate matters (PM_2.5 and PM₁₀) during the burning of biomass and liquefied petroleum gas (LPG) fuels and their impacts on the health of tribal women. The results revealed that the tribal women mainly used six types of unprocessed biomass fuels (dry leaves, cow dung cake, dry woods, twigs, rice straw, and agricultural residues) along with five types of traditional earthen stoves. The concentration of gaseous and PM was recorded as in the order of CO₂ > SO₂ > CO > O₃ and total suspended particulate matter (TSPM) > PM₁₀ > PM_2.5, respectively. The pollutant concentration inside the kitchen room for biomass users was significantly (p < 0.001) higher than LPG users. The biomass using tribal women might be suffering from higher cardiovascular risk than LPG users. The lung function study results also indicated that the mean values of forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC), and FEV₁/FVC were lower among biomass users than LPG users. The correlation study shows that tribal women who were exposed to biomass smoke were in a more vulnerable position than those who used LPG. Moreover, the toxicological risk among tribal biomass users was observed high (3.52) compared to LPG users (0.39). On the other hand, the Monte Carlo probabilistic simulation model for uncertainty analysis revealed that the mean value of Hazard Quotient (HQ) for PM_2.5 in kitchen room was observed as 4.31E-00 and 9.40E-01 for biomass and LPG users, respectively. Modelling study also revealed that exposure of duration and cooking time are extremely important for toxicological risk assessment. However, further long-term comprehensive studies are extremely important.

Association of Acute Respiratory Infections with Indoor Air Pollution from Biomass Fuel Exposure among Under-Five Children in Jimma Town, Southwestern Ethiopia

Background

Most of the households in developing countries burn biomass fuel in traditional stoves with incomplete combustion that leads to high indoor air pollution and acute respiratory infections. Acute respiratory infection is the most common cause of under-five morbidity and mortality accounting for 2 million deaths worldwide and responsible for 18% of deaths among under-five children in Ethiopia. Although studies were done on acute respiratory infections, the majority of studies neither clinically diagnose respiratory infections nor use instant measurement of particulate matter.

Methods

The community-based cross-sectional study design was employed among under-five children in Jimma town from May 21 to June 7, 2020. A total of 265 children through systematic random sampling were included in the study. The data were collected using a pretested semistructured questionnaire and laser pm 2.5 meter for indoor particulate matter concentration. Associations among factors were assessed through correlation analysis, and binary logistic regression was done to predict childhood acute respiratory infections. Variables with p-value less than 0.25 in bivariate regression were the candidate for the final multivariate logistic regression. Two independent sample t-tests were done to compare significant mean difference between concentrations of particulate matter.

Results

Among 265 under-five children who were involved in the study, 179 (67.5%) were living in households that predominantly use biomass fuel. Prevalence of acute respiratory infections in the study area was 16%. Children living in households that use biomass fuel were four times more likely to develop acute respiratory infections than their counterparts (AOR: 4.348; 95% CI: 1.632, 11.580). The size of household was significantly associated with the prevalence of acute respiratory infections. Under-five children living in households that have a family size of six and greater had odds of 1.7 increased risk of developing acute respiratory infections than their counterparts (AOR: 1.7; 95% CI: 1.299, 2.212). The other factor associated with acute respiratory infection was separate kitchen; children living in households in which there were no separate kitchen were four times at increased risk of developing acute respiratory infection than children living in households which have separate kitchen (AOR: 4.591; 95% CI: 1.849, 11.402). The concentration of indoor particulate matter was higher in households using biomass fuel than clean fuel. There was statistically higher particulate matter concentration in the kitchen than living rooms (t = 4.509, p ≤ 0.001). Particulate matter 2.5 concentrations (μg/m³) of the households that had parental smoking were significantly higher than their counterparts (AOR: 20.224; 95% CI: 1.72, 12.58).

Conclusion

There is an association between acute respiratory infections and biomass fuel usage among under-five children. Focusing on improved energy sources is essential to reduce the burden and assure the safety of children.

Comparison of Respiratory Health Impacts Associated with Wood and Charcoal Biomass Fuels: A Population-Based Analysis of 475,000 Children from 30 Low- and Middle-Income Countries

BACKGROUND

The World Health Organisation reported that 45% of global acute respiratory infection (ARI) deaths in children under five years are attributable to household air pollution, which has been recognised to be strongly associated with solid biomass fuel usage in domestic settings. The introduction of legislative restrictions for charcoal production or purchase can result in unintended consequences, such as reversion to more polluting biomass fuels such as wood; which may increase health and environmental harms. However, there remains a paucity of evidence concerning the relative health risks between wood and charcoal. This study compares the risk of respiratory symptoms, ARI, and severe ARI among children aged under five years living in wood and charcoal fuel households across 30 low- and middle-income countries.

METHODS

Data from children (N = 475,089) residing in wood or charcoal cooking households were extracted from multiple population-based Demographic and Health Survey databases (DHS) (N = 30 countries). Outcome measures were obtained from a maternal report of respiratory symptoms (cough, shortness of breath and fever) occurring in the two weeks prior to the survey date, generating a composite measure of ARI (cough and shortness of breath) and severe ARI (cough, shortness of breath and fever). Multivariable logistic regression analyses were implemented, with adjustment at individual, household, regional and country level for relevant demographic, social, and health-related confounding factors.

RESULTS

Increased odds ratios of fever (AOR: 1.07; 95% CI: 1.02-1.12) were observed among children living in wood cooking households compared to the use of charcoal. However, no association was observed with shortness of breath (AOR: 1.03; 95% CI: 0.96-1.10), cough (AOR: 0.99; 95% CI: 0.95-1.04), ARI (AOR: 1.03; 95% CI: 0.96-1.11) or severe ARI (AOR: 1.07; 95% CI: 0.99-1.17). Within rural areas, only shortness of breath was observed to be associated with wood cooking (AOR: 1.08; 95% CI: 1.01-1.15). However, an increased odds ratio of ARI was observed in Asian (AOR: 1.25; 95% CI: 1.04-1.51) and East African countries (AOR: 1.11; 95% CI: 1.01-1.22) only.

CONCLUSION

Our population-based observational data indicates that in Asia and East Africa there is a greater risk of ARI among children aged under 5 years living in wood compared to charcoal cooking households. These findings have major implications for understanding the existing health impacts of wood-based biomass fuel usage and may be of relevance to settings where charcoal fuel restrictions are under consideration.

Exploring smoke: an ethnographic study of air pollution in rural Malawi

Air pollution adversely affects human health, and the climate crisis intensifies the global imperative for action. Low-/middle-income countries (LMIC) suffer particularly high attributable disease burdens. In rural low-resource settings, these are linked to cooking using biomass. Proposed biomedical solutions to air pollution typically involve ‘improved cooking technologies’, often introduced by high-income country research teams. This ethnography, set in a rural Malawian village, aimed to understand air pollution within its social and environmental context. The results provide a multifaceted account through immersive participant observations with concurrent air quality monitoring, interviews and participatory workshops. Data included quantitative measures of individuals’ air pollution exposures paired with activity, qualitative insights into how smoke is experienced in daily life throughout the village, and participants’ reflections on potential cleaner air solutions. Individual air quality monitoring demonstrated that particulate levels frequently exceeded upper limits recommended by the WHO, even in the absence of identified sources of biomass burning. Ethnographic findings revealed the overwhelming impact of economic scarcity on individual air pollution exposures. Scarcity affected air pollution exposures through three pathways: daily hardship, limitation and precarity. We use the theory of structural violence, as described by Paul Farmer, and the concept of slow violence to interrogate the origins of this scarcity and global inequality. We draw on the ethnographic findings to critically consider sustainable approaches to cleaner air, without re-enacting existing systemic inequities.

Exposure to Air Pollution in Rural Malawi: Impact of Cooking Methods on Blood Pressure and Peak Expiratory Flow

We made static and personal PM2.5 measurements with a miniature monitor (RTI MicroPEM) to characterise the exposure of women cooking with wood and charcoal in indoor and outdoor locations in rural Malawi, together with measurements of blood pressure and peak expiratory flow rate (PEFR). Mean PM2.5 concentrations of 1338 and 31 µg/m3 were observed 1 m from cookstove locations during cooking with wood and charcoal, respectively. Similarly, mean personal PM2.5 exposures of 706 and 94 µg/m3 were observed during cooking with wood and charcoal, respectively. Personal exposures to PM2.5 in indoor locations were 3.3 and 1.7 times greater than exposures observed in equivalent outdoor locations for wood and charcoal, respectively. Prior to the measured exposure, six out of eight participants had PEFR observations below 80% of their expected (age and height) standardised PEFR. We observed reductions in PEFR for participants cooking with wood in indoor locations. Five out of eight participants reported breathing difficulties, coughing, and eye irritation when cooking with wood but reported that symptoms were less severe when cooking with charcoal. In conclusion, we observed that exposure to PM2.5 was substantially reduced by cooking outdoor with charcoal. As both wood and charcoal fuels are associated with negative environmental and health impacts, the adoption of high-efficiency cookstoves and less polluting sources of energy will be highly beneficial. Cooking outside whenever possible, and minimising the time spent in close proximity to stoves, may be simple interventions that could reduce the risks of exacerbation and progression of respiratory and cardiovascular diseases in Malawi.

Distribution of sources of household air pollution: a cross-sectional study in Cameroon

Background

Household air pollution (HAP) is a recognised risk factor for many diseases, including respiratory diseases, cardiovascular/circulatory disorders, adverse pregnancy outcomes and cataracts. Population exposure to biomass fuels, including wood, varies among countries and from one fuel source to the other. This study aimed to investigate the different sources of HAP in peri-urban and rural communities in Cameroon.

Methods

A cross-sectional survey was conducted in a representative sample of households from the Dschang Health District (DHD) region. This included 848 homes in which a range of fuels for cooking including biomass (firewood, charcoal, sawdust), kerosene and liquefied petroleum gas (LPG) were used both indoors and outdoors.

Results

Of the study households, 651 (77%) reported exclusive use of firewood and 141 (17%) reported using more than one source of fuel. Exclusive use of firewood was greater in rural communities (94%) than in peri-urban communities (38%). In peri-urban communities, use of multiple fuels including LPG, wood, sawdust and kerosene, was more common (44.75%). A total of 25.03% of households in both peri-urban and rural communities reported using bottled gas (or liquified petroleum gas (LPG) for cooking. Motivations for choice of fuel included, affordability, availability, rapidity, and cultural factors.

Conclusion

Wood is the main cooking fuel in both peri-urban and rural communities in the Dschang Health District. Supporting households (especially those with limited resources) to adopt LPG equipment for cooking, and use in a more exclusive way is required to help reduce household air pollution.

Improving Complementary Food Hygiene Behaviors Using the Risk, Attitude, Norms, Ability, and Self-Regulation Approach in Rural Malawi

The study evaluated the effectiveness of an intervention to improve complementary food hygiene behaviors among child caregivers in rural Malawi. Formative research and intervention development was grounded in the risk, attitude, norms, ability, and self-regulation (RANAS) model and targeted washing hands and kitchen utensils with soap, safe utensil storage, reheating of leftover food, and feeding of children by caregivers. Longitudinal research was applied at baseline and follow-up surveys among 320 caregivers. Determinants of selected behaviors were found, and interventions were developed based on the behavior change techniques aligned with these determinants in the RANAS model. The intervention was delivered over 9 months through group (cluster) meetings and household visits and included demonstrations, games, rewards, and songs. We randomly assigned villages to the control or intervention group. Follow-up results indicated a significant increase in three targeted behaviors (washing kitchen utensils with soap, safe utensil storage, and handwashing with soap) among intervention recipients. Several psychosocial factors differed significantly between the intervention and control groups. Mediation results showed that the intervention had a significant effect on these three targeted behaviors. For handwashing, feelings, others' behavior in the household, and remembering; for washing kitchen utensils, others' behavior in the household and difficulty to get enough soap; for safe utensils storage, others' behavior in the village and remembering mediated the effect of the intervention on the targeted behaviors. The study demonstrated that targeting food hygiene behaviors with a theory-driven behavior change approach using psychosocial factors can improve the behavior of child caregivers in rural Malawi.

Impact of wood combustion on indoor air quality

The incomplete wood combustion in appliances operated in batch mode is a recognised source of both in- and outdoor airborne pollutants, especially particulate matter (PM). Data on pollutant levels and PM characteristics in households with wood burning devices in developed countries are scarce with most studies describing stove change out programmes or other intervention measures. The aim of the present study was to simultaneously evaluate indoor and outdoor concentrations of CO, CO₂ and PM₁₀ during the operation of wood burning appliances (open fireplace and woodstove) in unoccupied rural households. PM₁₀ samples were analysed for water soluble inorganic ions, major and trace elements, organic carbon (OC), elemental carbon (EC), and detailed organic speciation. The CO 8-hour average concentrations did not exceed the protection limit despite the sharp increases observed in relation to background levels. During the open fireplace operation, PM₁₀ levels rose up 12 times compared to background concentrations, while the airtight stove resulted in a 2-fold increase. The inhalation cancer risk of particulate bound PAHs in the room equipped with woodstove was estimated to be negligible while the long-term exposure to PAH levels measured in the fireplace room may contribute to the development of cancer. The excess lifetime cancer risk resulting from the particle-bound Cr(VI) exposure during the fireplace and woodstove operation was higher than 1.0 × 10^-6 and 1.0 × 10^-5, respectively. Levoglucosan was one of the most abundant individual species both indoors and outdoors. This study underlines air pollution hazards and risks arising from the operation of traditional wood burning appliances.

A cross-sectional analysis of respiratory ill-health among charcoal workers and its implications for strengthening occupational health services in southern Nigeria

OBJECTIVES

This study was conducted to assess the concentration of air pollutants at charcoal sites, the dose-response relationship between site-based exposure levels to air pollutants and prevalence of respiratory symptoms among charcoal workers, and the measures these workers employ to safeguard their health.

DESIGN

Cross-sectional but comparative design SETTING: Charcoal production kiln sites in Sapele, Delta State, Nigeria.

PARTICIPANTS

Overall 296 charcoal workers and age-matched, sex-matched and height-matched non-exposed traders (comparison group).

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome measure was the prevalence of respiratory symptoms among charcoal workers while secondary outcomes included lung function indices as well as hazard control practices among charcoal workers.

RESULTS

Majority (83.3%) of the sites had PM10 and PM2.5 values five times higher than the WHO standard. Charcoal workers were more likely to have respiratory symptoms; wheeze was statistically significant after adjusting for confounders, (OR 4.22; CI 1.37 to 12.99). The dose-response relationship between site-based exposure levels to air pollutants and the prevalence of respiratory symptoms among charcoal workers was statistically significant for all symptoms except chest tightness (p=0.167). Mean forced expiratory volume in the first second (FEV1) and forced vital capacity (FVC) were considerably lower among workers with differences of -0.22 (-0.42 to -0.05) L and -0.52 (-0.76 to -0.29) L, respectively, whereas FEV1/FVC ratio and peak expiratory flow rate were higher among workers with mean differences of 5.68 (3.59-8.82)% and 0.31 (-23.70 to 24.43) L/min, respectively; but the mean difference was significant only for the FEV1/FVC ratio. Charcoal workers had poor hazard control practices; only 3.4% reportedly used personal protective equipment.

CONCLUSION

Air pollutants at kiln sites were higher than WHO standards. Despite the significantly higher prevalence of wheeze, chest tightness and chronic cough among charcoal workers, their hazard control practices were inadequate. Charcoal workers should adopt appropriate hazard control practices, and use improved devices which emit minimal pollutants.

The Cooking and Pneumonia Study (CAPS) in Malawi: A Cross-Sectional Assessment of Carbon Monoxide Exposure and Carboxyhemoglobin Levels in Children under 5 Years Old

Household air pollution is estimated to cause half a million deaths from pneumonia in children worldwide. The Cooking and Pneumonia Study (CAPS) was conducted to determine whether the use of cleaner-burning biomass-fueled cookstoves would reduce household air pollution and thereby the incidence of pneumonia in young children in rural Malawi. Here we report a cross-sectional assessment of carbon monoxide (CO) exposure and carboxyhemoglobin (COHgB) levels at recruitment to CAPS. Mean (SD; range) 48-h CO exposure of 1928 participating children was 0.90 (2.3; 0–49) ppm and mean (SD; range) COHgB level was 5.8% (3.3; 0–20.3). Higher mean CO and COHgB levels were associated with location (Chikhwawa versus Chilumba) (OR 3.55 (1.73–7.26)); (OR 2.77 (1.08–7.08)). Correlation between mean CO and COHgB was poor (Spearman’s ρ = 0.09, p < 0.001). The finding of high COHgB levels in young children in rural Malawi that are at levels at which adverse neurodevelopmental and cognitive effects occur is of concern. Effective approaches for reducing exposure to CO and other constituents of air pollution in rural sub-Saharan African settings are urgently needed.

Effects of biomass burning on pulmonary functions in tribal women in northeastern India

Wood smoke causes adverse effects on pulmonary function (PF) in women in developing countries. This study compared PF among rural tribal women in northeastern India among 266 wood users and 82 liquefied petroleum gas (LPG) users, all healthy nonsmoking women from April to July, 2014. PF measurements included FVC, FEV₁, FEV₁/FVC, PEF, and FEF_25-75%. Information on participants' health status, demographic, and socioeconomic characteristics were collected by questionnaire. Multiple linear regressions were performed to compare PF between the two groups, adjusting for potential confounders. Wood users had significantly lower pulmonary values than LPG users: FVC (2.65 vs. 2.85 L, p < .001), FEV₁ (1.46 vs. 1.92 L, p < .001), PEF (1.89 vs. 2.56 L/s, p < .001), and FEF_25-75% (1.12 vs. 1.68 L/s, p < .001) except for FEV₁/FVC (76.5 vs. 75.5 percent, p = .27). Wood use was associated with 7 percent lower FVC, 24 percent lower FEV₁, 1.3 percent lower FEV₁/FVC, 26 percent lower PEF, and 33 percent lower FEEF_25-75% compared to LPG use. Wood use was associated with a 0.27-L decrease in FEV₁, adjusted for covariates. Women cooking with wood had lower PF and more respiratory symptoms and gastritis than those using LPG. Thus, reducing indoor air pollution from biomass burning is needed to protect tribal women's health.

The increasing prevalence of non-communicable diseases in low-middle income countries: the view from Malawi

Non-communicable diseases (NCDs) are the leading cause of death globally, the majority of these being due to cardiovascular disease, cancer, chronic respiratory diseases, or diabetes. Mortality from many NCDs continues to increase worldwide, with a disproportionately larger impact in low-middle income countries (LMIs), where almost 75% of global deaths occur from these causes. As a low-income African country that consistently ranks amongst the world's poorest nations, Malawi as a case study demonstrates how transition due to societal change and increasing urbanization is often accompanied by a rise in the rate of NCDs. Other factors apart from changing lifestyle factors can explain at least some of this increase, such as the complex relationship between communicable and NCD and growing environmental, occupational, and cultural pressures. Malawi and other LMIs are struggling to manage the increasing challenge of NCDs, in addition to an already high communicable disease burden. However, health care policy implementation, specific health promotion campaigns, and further epidemiological research may be key to attenuating this impending health crisis, both in Malawi and elsewhere. This review aims to examine the effects of the major NCDs in Malawi to help inform future public health care policy in the region.

Sources and levels of particulate matter in North African and Sub-Saharan cities: a literature review

In order to assess the significance of PM in ambient air, it is necessary to evaluate their physical and chemical characteristics as well as identify their major emission sources. On a global scale, particulate matter in the atmosphere arises mainly from the combustion process of motorized vehicles, but natural sources are still considered as the major contributors. In Africa, PM emissions differ from those in developed countries; human activities such as biomass burning in households, poor household waste management, and the high number of diesel-powered vehicles are the predominant anthropogenic sources. Natural contributions are also observed. Saharan dust and savanna fires are the most common atmospheric natural sources of particulate matter. The present literature review gives an overview of the status of air quality in African cities and highlights the various sources of particulate matter emissions and local human activities specific to each African region. This could likely serve as a reference to evaluate the current air quality in this region and will be a useful tool in the future to develop pollution mitigation strategies at the source. Recommendations are proposed in the conclusion in order to reduce emissions from their sources, taking into account the low-income African countries.

Prevalence, risk factors and clinical correlates of COPD in a rural setting in Tanzania

Chronic obstructive pulmonary disease (COPD) causes substantial burden of disease in developed countries, but there are limited data from Africa. We aimed to estimate the prevalence of COPD in Tanzania and identify the risk factors associated with it.This was a cross-sectional descriptive survey involving adults aged ≥35 years. We collected data on symptoms and risk factors using the Burden of Obstructive Lung Diseases questionnaire. Spirometry was performed and COPD diagnosed based on post-bronchodilator forced expiratory volume in 1 s/forced vital capacity <70%. We also measured indoor and outdoor carbon monoxide (CO) levels.A total of 869 participants (49.1% females) completed the questionnaires. Of these, 57.1% completed post-bronchodilator spirometry. Of the 25.2% ever-smokers, only 5.4% were current smokers. COPD prevalence was estimated at 17.5% (21.7% in males and 12.9% in females). COPD was associated with a history of cough, phlegm production and wheezing. 51.7% of COPD patients reported cough and 85% had mild to moderate airway limitation. Females had a higher rate of exacerbation. Pulmonary tuberculosis (TB) was reported in 10% of patients. Only 1.7% of patients who were diagnosed as COPD had ever received any medication, with only one female COPD patient having received an inhaler. 99.5% of the population used biomass fuels for cooking. The majority of households had CO levels up to 20 ppm.The prevalence of COPD in Tanzania is high, with a peak at a relatively young age and a preponderance in males. A history of TB, cigarette smoking and male sex are important risk factors. Indoor air pollution coupled with use of biomass fuel for cooking and heating may be an important risk factor for developing COPD in rural Tanzania. However, these factors need to be studied further.

Fuel Efficiency and Air Pollutant Concentrations of Wood-Burning Improved Cookstoves in Malawi: Implications for Scaling-up Cookstove Programs

National governments and other key stakeholders in developing countries are grappling with how to reduce household air pollution (HAP) resulting from cooking with solid fuels using traditional cooking technologies. Recent studies have shown that improved cookstoves may offer reductions in fuel use and harmful emissions of carbon monoxide (CO) and fine particulate matter (PM2.5), yet there is little quantitative evidence collected in a "real-world" setting showing how improved stoves perform directly compared to traditional cooking technologies. Our simulated kitchen study takes place in a semi-controlled, "real-world" setting in Malawi and was designed to quantify the fuel efficiency improvements and air pollutant concentration reductions capabilities of two improved stoves currently marketed in the country. In this study, we perform a Water Boiling Test (WBT) to compare the air pollutant concentrations (CO and PM2.5) and fuel efficiency of the traditional three-stone fire stove and two improved cookstoves: a locally produced clay stove known as the Chitetezo Mbaula (CM) and a Philips gasifying stove. We find that the Chitetezo Mbaula uses 53% of the fuel used by the traditional three-stone fire, and produces 59% of CO, and 50% of PM2.5 of the three-stone fire. The Philips gasifying stove uses 31% of the fuel, and produces 38% of CO, and 22% of PM2.5 of the traditional three-stone fire. We consider the potential for the wide-scale adoption of each of these technologies given their relative costs and conclude that lower-cost, intermediate quality cookstoves are an important and realistic first step toward reducing household air pollution.

Impact of partial fuel switch on household air pollutants in sub-Sahara Africa

Over 700 million people in Sub-Saharan Africa depend on solid biomass fuel and use simple cookstoves in poorly ventilated kitchens, which results in high indoor concentrations of household air pollutants. Switching from biomass to biogas as a cooking fuel can reduce airborne emissions of fine particulate matter (PM_2.5) and carbon monoxide (CO), but households often only partially convert to biogas, continuing to use solid biomass fuels for part of their daily cooking needs. There is little evidence of the benefits of partial switching to biogas. This study monitored real-time PM_2.5 and CO concentrations in 35 households in Cameroon and Uganda where biogas and firewood (or charcoal) were used. The 24 h mean PM_2.5 concentrations in households that used: (1) firewood and charcoal; (2) both firewood (mean 54% cooking time) and biogas (mean 46% cooking time); and (3) only biogas, were 449 μg m^-3, 173 μg m^-3 and 18 μg m^-3 respectively. The corresponding 24 h mean CO concentrations were 14.2 ppm, 2.7 ppm and 0.5 ppm. Concentrations of both PM_2.5 and CO were high and exceeded the World Health Organisation guidelines when firewood and charcoal were used. Partially switching to biogas reduced CO exposure to below the World Health Organisation guidelines, but PM_2.5 concentrations were only below the 24 h recommended limits when households fully converted to biogas fuel. These results indicate that partial switching from solid fuels to biogas is not sufficient and continues to produce concentrations of household air pollution that are likely to harm the health of those exposed. Programmes introducing biogas should aim to ensure that household energy needs can be fully achieved using biogas with no requirement to continue using solid fuels.

Household air pollution, chronic respiratory disease and pneumonia in Malawian adults: A case-control study

Background: Four million people die each year from diseases caused by exposure to household air pollution. There is an association between exposure to household air pollution and pneumonia in children (half a million attributable deaths a year); however, whether this is true in adults is unknown. We conducted a case-control study in urban Malawi to examine the association between exposure to household air pollution and pneumonia in adults.

Methods: Hospitalized patients with radiologically confirmed pneumonia (cases) and healthy community controls underwent 48 hours of ambulatory and household particulate matter (µg/m ³) and carbon monoxide (ppm) exposure monitoring. Multivariate logistic regression, stratified by HIV status, explored associations between these and other potential risk factors with pneumonia.

Results: 145 (117 HIV-positive; 28 HIV-negative) cases and 253 (169 HIV-positive; 84 HIV-negative) controls completed follow up. We found no evidence of association between household air pollution exposure and pneumonia in HIV-positive (e.g. ambulatory particulate matter adjusted odds ratio [aOR] 1.00 [95% CI 1.00–1.01, p=0.141]) or HIV-negative (e.g. ambulatory particulate matter aOR 1.00 [95% CI 0.99–1.01, p=0.872]) participants. Chronic respiratory disease was associated with pneumonia in both HIV-positive (aOR 28.07 [95% CI 9.29–84.83, p<0.001]) and HIV-negative (aOR 104.27 [95% CI 12.86–852.35, p<0.001]) participants.

Conclusions: We found no evidence that exposure to household air pollution is associated with pneumonia in Malawian adults. In contrast, chronic respiratory disease was strongly associated with pneumonia.

A health intervention or a kitchen appliance? Household costs and benefits of a cleaner burning biomass-fuelled cookstove in Malawi

Pneumonia is the leading cause of mortality for children under five years in sub-Saharan Africa. Household air pollution has been found to increase risk of pneumonia, especially due to exposure from dirty burning biomass fuels. It has been suggested that advanced stoves, which burn fuel more efficiently and reduce smoke emissions, may help to reduce household air pollution in poor, rural settings.

This qualitative study aims to provide an insight into the household costs and perceived benefits from use of the stove in Malawi. It was conducted alongside The Cooking and Pneumonia Study (CAPS), the largest village cluster-level randomised controlled trial of an advanced combustion cookstove intervention to prevent pneumonia in children under five to date. In 2015, using 100 semi-structured interviews this study assessed household time use and perceptions of the stove from both control and intervention participants taking part in the CAPS trial in Chilumba. Household direct and indirect costs associated with the intervention were calculated.

Users overwhelming liked using the stove. The main reported benefits were reduced cooking times and reduced fuel consumption. In most interviews, the health benefits were not initially identified as advantages of the stove, although when prompted, respondents stated that reduced smoke emissions contributed to a reduction in respiratory symptoms. The cost of the stove was much higher than most respondents said they would be willing to pay.

The stoves were not primarily seen as health products. Perceptions of limited impact on health was subsequently supported by the CAPS trial data which showed no significant effect on pneumonia. While the findings are encouraging from the perspective of acceptability, without innovative financing mechanisms, general uptake and sustained use of the stove may not be possible in this setting. The findings also raise the question of whether the stoves should be marketed and championed as ‘health interventions’.

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The first evaluation of household perceptions of an advanced cookstove trial in Malawi.

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We investigate the intensive margin, i.e. how the technology is used and perceived.

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Significant benefits from reduced cooking and fuel collection times were reported.

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Unless prompted, respondents rarely associated the stoves with health benefits.

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The high cost of the advanced cookstove will need addressing to ensure future uptake.

Biomass Cooking Fuels and Health Outcomes for Women in Malawi

In sub-Saharan Africa, biomass fuels account for approximately 90% of household energy consumption. Limited evidence exists on the association between different biomass fuels and health outcomes. We report results from a cross-sectional sample of 655 households in Malawi. We calculated odds ratios between hypothesized determinants of household air pollution (HAP) exposure (fuel, stove type, and cooking location) and five categories of health outcomes (cardiopulmonary, respiratory, neurologic, eye health, and burns). Reliance on high- or low-quality firewood or crop residue (vs. charcoal) was associated with significantly higher odds of shortness of breath, difficulty breathing, chest pains, night phlegm, forgetfulness, dizziness, and dry irritated eyes. Use of high-quality firewood was associated with significantly lower odds of persistent phlegm. Cooks in rural areas (vs. urban areas) had significantly higher odds of experiencing shortness of breath, persistent cough, and phlegm, but significantly lower odds of phlegm, forgetfulness, and burns. With deforestation and population pressures increasing reliance on low-quality biomass fuels, prevalence of HAP-related cardiopulmonary and neurologic symptoms will likely increase among cooks. Short- to medium-term strategies are needed to secure access to high-quality biomass fuels given limited potential for scalable transitions to modern energy.

Household air pollution following replacement of traditional open fire with an improved rocket type cookstove

Cooking with biomass fuel is an important source of household air pollution (HAP) in developing countries, and a leading risk factor for ill-health. Although various designs of "improved cookstoves" (ICS) have been promoted as HAP interventions in these settings, few of them have undergone in-field evaluation, partly due to the challenge of conducting field measurements in remote settings. In this study we assessed the change in carbon monoxide (CO) exposure following the replacement of the traditional three-stone stove with a popular ICS in 49 homes in Western Kenya. We also assessed the suitability of using kitchen CO as a proxy for kitchen PM_2.5. Reduction in 48h mean kitchen CO was 3.1ppm (95% CI: -8.1, 1.8) and in personal CO was 0.9ppm (95% CI: -4.3, 2.6) following stove replacements. Overall, 48-h kitchen and personal CO exposures were lower after stove replacement (28% and 12%, respectively) but with wide confidence intervals that also suggested possible increases in exposure. There were statistically significant reductions in peak kitchen and personal CO concentrations represented by the 8-h 95th percentile: reductions of 26.1ppm (95% CI: -44.6, -7.6) and 8.0ppm (95% CI: -12.2, -3.8), respectively. This is equivalent to 53% reduction in kitchen CO and 39% reduction in personal CO. We found good correlation between kitchen CO and PM_2.5 concentrations overall (r=0.73, n=33 over averaging periods approximating 1day), which varied by time of day and exposure setting. These variations limit the applicability of CO as a proxy measure for PM_2.5 concentrations. A combination of interventions, including better designed stoves, improved ventilation and cleaner fuels, may be needed to reduce HAP to levels that are likely to improve health.

A cleaner burning biomass-fuelled cookstove intervention to prevent pneumonia in children under 5 years old in rural Malawi (the Cooking and Pneumonia Study): a cluster randomised controlled trial

BACKGROUND

WHO estimates exposure to air pollution from cooking with solid fuels is associated with over 4 million premature deaths worldwide every year including half a million children under the age of 5 years from pneumonia. We hypothesised that replacing open fires with cleaner burning biomass-fuelled cookstoves would reduce pneumonia incidence in young children.

METHODS

We did a community-level open cluster randomised controlled trial to compare the effects of a cleaner burning biomass-fuelled cookstove intervention to continuation of open fire cooking on pneumonia in children living in two rural districts, Chikhwawa and Karonga, of Malawi. Clusters were randomly allocated to intervention and control groups using a computer-generated randomisation schedule with stratification by site, distance from health centre, and size of cluster. Within clusters, households with a child under the age of 4·5 years were eligible. Intervention households received two biomass-fuelled cookstoves and a solar panel. The primary outcome was WHO Integrated Management of Childhood Illness (IMCI)-defined pneumonia episodes in children under 5 years of age. Efficacy and safety analyses were by intention to treat. The trial is registered with ISRCTN, number ISRCTN59448623.

FINDINGS

We enrolled 10 750 children from 8626 households across 150 clusters between Dec 9, 2013, and Feb 28, 2016. 10 543 children from 8470 households contributed 15 991 child-years of follow-up data to the intention-to-treat analysis. The IMCI pneumonia incidence rate in the intervention group was 15·76 (95% CI 14·89-16·63) per 100 child-years and in the control group 15·58 (95% CI 14·72-16·45) per 100 child-years, with an intervention versus control incidence rate ratio (IRR) of 1·01 (95% CI 0·91-1·13; p=0·80). Cooking-related serious adverse events (burns) were seen in 19 children; nine in the intervention and ten (one death) in the control group (IRR 0·91 [95% CI 0·37-2·23]; p=0·83).

INTERPRETATION

We found no evidence that an intervention comprising cleaner burning biomass-fuelled cookstoves reduced the risk of pneumonia in young children in rural Malawi. Effective strategies to reduce the adverse health effects of household air pollution are needed.

FUNDING

Medical Research Council, UK Department for International Development, and Wellcome Trust.

Air quality index from charcoal production sites, carboxyheamoglobin and lung function among occupationally exposed charcoal workers in South Western Nigeria

Charcoal production is often accompanied with gaseous and particulate emission into the atmosphere and occupationally exposed workers could be affected. This cross sectional comparative study was carried out to assess the levels of carbon monoxide (CO), carbon dioxide (CO2), sulphur dioxide (SO2), nitrogen dioxide (NO2) and particulate matter (PM2.5) generated during the phases of charcoal production and their relationship with certain biomarkers among charcoal workers (subjects) and non-charcoal workers (controls) such as carboxyhaemoglobin (COHb), forced expiratory volume in the first second of expiration (FEV1), peak expiratory flow rate (PEFR) and body mass index (BMI) in Igbo-Ora, Oyo State and Alabata, Ogun State, which are two of the major hubs of charcoal production in South Western Nigeria. Four communities in Igbo-Ora and six communities in Alabata were purposively selected and levels of pollutant gases were assessed using appropriate gas meters, PM2.5 was assessed with Thermo Scientific MIE pDR-1500, FEV1 and PEFR were measured with Piko-1 spirometer while COHb was assessed using non-invasive pulse CO-oximeter (Rad 57). Data were statistically analyzed and results were compared with recommended guidelines. The mean FEV1, PEFR, COHb and BMI for subjects and controls were 2.35 ± 0.73 and 2.69 ± 0.56, 253.72 ± 103.45 and 330.02 ± 94.61 (p < 0.01), 13.28 ± 3.91 and 8.50 ± 3.68 (p < 0.01) and 21.97 ± 2.19 and 23.36 ± 3.74 (p < 0.05) respectively. There was a statistically significant difference between actual and expected values of FEV1 (p < 0.01) and PEFR (p < 0.01) among charcoal workers. There existed a positive correlation between CO and COHb while FEV1 and PEFR correlated negatively with PM2.5. The study showed that charcoal workers are exposed to high levels of CO and PM2.5, contributing to lowered respiratory functions for FEV1 and PEFR and high levels of COHb compared to the control group. Routine respiratory and carboxyheamoglobin assessment of persons involved in charcoal production is also recommended.

Household Air Pollution: Sources and Exposure Levels to Fine Particulate Matter in Nairobi Slums

With 2.8 billion biomass users globally, household air pollution remains a public health threat in many low- and middle-income countries. However, little evidence on pollution levels and health effects exists in low-income settings, especially slums. This study assesses the levels and sources of household air pollution in the urban slums of Nairobi. This cross-sectional study was embedded in a prospective cohort of pregnant women living in two slum areas—Korogocho and Viwandani—in Nairobi. Data on fuel and stove types and ventilation use come from 1058 households, while air quality data based on the particulate matters (PM_2.5) level were collected in a sub-sample of 72 households using the DustTrak™ II Model 8532 monitor. We measured PM_2.5 levels mainly during daytime and using sources of indoor air pollutions. The majority of the households used kerosene (69.7%) as a cooking fuel. In households where air quality was monitored, the mean PM_2.5 levels were high and varied widely, especially during the evenings (124.6 µg/m³ SD: 372.7 in Korogocho and 82.2 µg/m³ SD: 249.9 in Viwandani), and in households using charcoal (126.5 µg/m³ SD: 434.7 in Korogocho and 75.7 µg/m³ SD: 323.0 in Viwandani). Overall, the mean PM_2.5 levels measured within homes at both sites (Korogocho = 108.9 µg/m³ SD: 371.2; Viwandani = 59.3 µg/m³ SD: 234.1) were high. Residents of the two slums are exposed to high levels of PM_2.5 in their homes. We recommend interventions, especially those focusing on clean cookstoves and lighting fuels to mitigate indoor levels of fine particles.

Stoves or Sugar? Willingness to Adopt Improved Cookstoves in Malawi

Malawi has set a target of adoption of two million improved cookstoves (ICS) by 2020. Meeting this objective requires knowledge about determinants of adoption, particularly in rural areas where the cost of traditional cooking technologies and fuels are non-monetary, and where people have limited capacity to purchase an ICS. We conducted a discrete choice experiment with 383 households in rural Malawi asking them if they would chose a locally made ICS or a package of sugar and salt of roughly equal value. Six months later, we assessed adoption and stove use patterns. Sixty-six percent of households chose the ICS. We find that having a larger share of crop residues in household fuel supply, awareness of the environmental impacts of woodfuel reliance, time the primary cook devotes to collecting fuelwood, and peer effects at the village-level increase the odds of choosing the ICS. Having a large labor supply for fuelwood collection and experience with a non-traditional cooking technology decreased the odds of choosing the ICS. In a rapid assessment six months after stoves were distributed, we found 80% of households were still using the ICS, but not exclusively. Our findings suggest considerable potential for wide-scale adoption of ICS in Malawi.

Study protocol: the effects of air pollution exposure and chronic respiratory disease on pneumonia risk in urban Malawian adults--the Acute Infection of the Respiratory Tract Study (The AIR Study)

Background

Pneumonia is the 2nd leading cause of years of life lost worldwide and is a common cause of adult admissions to hospital in sub-Saharan Africa. Risk factors for adult pneumonia are well characterised in developed countries, but are less well described in sub-Saharan Africa where HIV is a major contributing factor. Exposure to indoor and outdoor air pollution is high, and tobacco smoking prevalence is increasing in sub-Saharan Africa, yet the contribution of these factors to the burden of chronic respiratory diseases in sub-Saharan Africa remains poorly understood. Furthermore, the extent to which the presence of chronic respiratory diseases and exposure to air pollution contribute to the burden of pneumonia is not known.

Design

The Acute Infection of the Respiratory Tract Study (The AIR Study) is a case–control study to identify preventable risk factors for adult pneumonia in the city of Blantyre, Malawi. Cases will be adults admitted with pneumonia, recruited from Queen Elizabeth Central Hospital, the largest teaching hospital in Malawi. Controls will be adults without pneumonia, recruited from the community. The AIR Study will recruit subjects and analyse data within strata defined by positive and negative HIV infection status. All participants will undergo thorough assessment for a range of potential preventable risk factors, with an emphasis on exposure to air pollution and the presence of chronic respiratory diseases. This will include collection of questionnaire data, clinical samples (blood, urine, sputum and breath samples), lung function data and air pollution monitoring in their home. Multivariate analysis will be used to identify the important risk factors contributing to the pneumonia burden in this setting. Identification of preventable risk factors will justify research into the effectiveness of targeted interventions to address this burden in the future.

Discussion

The AIR Study is the first study of radiologically confirmed pneumonia in which air pollution exposure measurements have been undertaken in this setting, and will contribute important new information about exposure to air pollution in urban SSA. Through identification of preventable risk factors, the AIR Study aims to facilitate future research and implementation of targeted interventions to reduce the high burden of pneumonia in SSA.

Contrasts in spatial and temporal variability of oxidative capacity and elemental composition in moxibustion, indoor and outdoor environments in Beijing

Moxibustion is a traditional Chinese medicine therapy that burns moxa floss which produces a substantial amount of PM10 into the environment, thus spawning safety concerns about health impacts of the smoke. We compared the oxidative capacity and elemental composition of moxibustion-derived and ambient PM10 in summer and winter to provide a source-, spatial- and temporal-comparison of PM10 biological responses. The PM10 oxidative capacity was 2.04 and 1.45 fold lower, and dose-dependent slope gradient was 2.36 and 1.76 fold lower in moxibustion environment than indoor or outdoor. Oxidative damage was highly correlated with iron, cesium, aluminum and cobalt in indoor, but moxibustion environment displayed low associations. The total elemental concentration was also lower in moxibustion environment than indoor (2.28 fold) or outdoor (2.79 fold). The source-to-dose modeling and slope gradient analysis in this study can be used as a model for future source-, spatial- and temporal-related moxibustion safety evaluation studies.

A cross-sectional study of household biomass fuel use among a periurban population in Malawi

RATIONALE

The Global Burden of Disease Study suggests almost 3.5 million people die as a consequence of household air pollution every year. Respiratory diseases including chronic obstructive pulmonary disease and pneumonia in children are strongly associated with exposure to household air pollution. Smoke from burning biomass fuels for cooking, heating, and lighting is the main contributor to high household air pollution levels in low-income countries like Malawi. A greater understanding of biomass fuel use in Malawi should enable us to address household air pollution-associated communicable and noncommunicable diseases more effectively.

OBJECTIVES

To conduct a cross-sectional analysis of biomass fuel use and population demographics among adults in Blantyre, Malawi.

METHODS

We used global positioning system-enabled personal digital assistants to collect data on location, age, sex, marital status, education, occupation, and fuel use. We describe these data and explore associations between demographics and reported fuel type.

MEASUREMENTS AND MAIN RESULTS

A total of 16,079 adults participated (nine households refused); median age was 30 years, there was a similar distribution of men and women, 60% were married, and 62% received secondary school education. The most commonly reported occupation for men and women was "salaried employment" (40.7%) and "petty trader and marketing" (23.5%), respectively. Charcoal (81.5% of households), wood (36.5%), and electricity (29.1%) were the main fuels used at home. Only 3.9% of households used electricity exclusively. Lower educational and occupational attainment was associated with greater use of wood.

CONCLUSIONS

This large cross-sectional study has identified extensive use of biomass fuels in a typical sub-Saharan Africa periurban population in which women and people of lower socioeconomic status are disproportionately affected. Biomass fuel use is likely to be a major driver of existing communicable respiratory disease and the emerging noncommunicable disease (especially respiratory and cardiovascular) epidemic in this region. Our data will help inform the rationale for specific intervention studies and the development of appropriately targeted public health strategies to tackle this important and poverty-related global health problem.

Risk factors for chronic obstructive pulmonary disease among never-smokers in Korea

Background

Chronic obstructive pulmonary disease (COPD) patients include those who have never smoked. However, risk factors other than smoking in never-smokers have not been elucidated sufficiently. This study investigated the risk factors for COPD among never-smokers in Korea using population-based data.

Methods

The data were retrieved from the Korean National Health and Nutrition Survey IV conducted from 2007 to 2009. Among subjects aged 40 years or older who underwent appropriate pulmonary function tests, never-smokers not diagnosed with asthma and not showing a restrictive pattern on pulmonary function tests were enrolled. Risk factors of COPD in never-smokers were analyzed using logistic regression models.

Results

Among 24,871 participants in the representative Korean cohort, 3,473 never-smokers were enrolled. COPD patients accounted for 7.6% of the never-smokers. In the logistic regression analysis, low education status (odds ratio [OR]: 2.0; 95% confidence interval [CI]: 1.2–3.2), occupational exposure (OR: 2.6; 95% CI: 1.3–5.3), a history of tuberculosis (OR: 4.5; 95% CI: 2.3–8.7), bronchiectasis (OR: 6.0; 95% CI: 1.4–25.4), male sex (OR: 4.2; 95% CI: 2.6–6.7), advanced age (60–69 years vs 40–49 years; OR: 3.8; 95% CI: 2.0–7.0), and being underweight (body mass index <18.5 vs 18.0–24.9 kg/m²; OR: 3.1; 95% CI: 1.0–9.4) were associated with the development of COPD.

Conclusion

Low education status, manual labor, a history of tuberculosis and bronchiectasis, as well as male sex, advanced age and being underweight were risk factors for COPD in Korean never-smokers.

Feasibility of conducting a randomised controlled trial of a cookstove intervention in rural Malawi

BACKGROUND:

Exposure to household air pollution (HAP) causes 4 million deaths annually, and strategies to reduce HAP exposure are urgently required.

OBJECTIVE:

To evaluate the acceptability and feasibility of conducting a trial of a cookstove intervention in rural Malawi.

DESIGN:

Non-smoking women were randomised to continuing to use an open fire (control) or to using a wood-burning clay cookstove (intervention). Symptom burden, oxygen saturation and exhaled carbon monoxide (eCO) were assessed at baseline and 7-day follow-up. A subset of women underwent HAP exposure monitoring.

Of 51 women recruited, 50 (98%) completed the main study. The methodology was acceptable to participants. Headache, back pain and cough were the most commonly reported symptoms at baseline and follow-up. Median eCO was within normal limits, but with a difference of 0.5 parts per million (ppm) in median change of eCO from baseline to follow-up seen between the two groups (P ∙ 0.035). The peak ambient CO concentration detected was 150 ppm.

This study suggests that a large cookstove intervention trial in Malawi would be feasible with careful community sensitisation. Monitoring exposure to HAP is challenging, and further studies evaluating potential biomarkers of exposure, including eCO, should be undertaken.

Increased oxidative DNA damage and decreased expression of base excision repair proteins in airway epithelial cells of women who cook with biomass fuels

To investigate whether biomass burning causes oxidative DNA damage and alters the expression of DNA base excision repair (BER) proteins in airway cells, sputum samples were collected from 80 premenopausal rural biomass-users and 70 age-matched control women who cooked with liquefied petroleum gas. Compared with control the airway cells of biomass-users showed increased DNA damage in alkaline comet assay. Biomass-users showed higher percentage of cells expressing oxidative DNA damage marker 8-oxoguanine and lower percentages of BER proteins OGG1 and APE1 by immunocytochemical staining. Reactive oxygen species (ROS) generation was doubled and level of superoxide dismutase was depleted significantly among biomass-users. The concentrations of particulate matters were higher in biomass-using households which positively correlated with ROS generation and negatively with BER proteins expressions. ROS generation was positively correlated with 8-oxoguanine and negatively with BER proteins suggesting cooking with biomass is a risk for genotoxicity among rural women in their child-bearing age.

Respiratory symptoms, lung function and particulate matter pollution in residential indoor environment in Ile-Ife, Nigeria

Introduction:

Particulate air pollution is associated with increased incidence of respiratory symptoms and decreased pulmonary, function but the relative impact of pollution from different domestic energy sources is not well-known or studied.

Aim:

The study was aimed at assessing the association between particulate concentrations, respiratory symptoms and lung function.

Materials and Methods:

It was a cross-sectional study comprised of randomly selected residents of three communities. These communities were selected according to the predominant type of fuel used for household cooking which were: firewood, kerosene and liquefied petroleum gas (LPG). Assessment of the indoor PM₁₀ levels was done by filtration using the Gent stacked filter unit sampler for collection of atmospheric aerosol in two size fractions (PM_2.5 and PM₁₀). The Medical Research Council (MRC) questionnaire was administered followed by spirometry test.

Results:

The mean PM₁₀ concentration in participants using LPG, kerosene and firewood was 80.8 ± 9.52 μg/m³, 236.9 ± 26.5 μg/m³ and 269 ±93.7 μg/m³, respectively. The mean age and height-adjusted percent predicted forced expiratory volumes in 1 s (FEV1) for men were 127 ± 7, 109 ± 40 and 91 ± 20 and for women were 129 ± 13, 115 ± 14, 100 ± 14 in users of LPG, kerosene and firewood, respectively. A similar trend was found in the forced vital capacity (FVCs). Users of firewood had significantly lower FEV1 and FVC compared with LPG users (P < 0.05). The participants using firewood had the highest prevalence of pulmonary and non-pulmonary symptoms (57.1%), whereas subjects using LPG had the lowest (23.8%).

Conclusion:

There are high levels of particulate matter pollutions with respiratory effects in residential indoor environments in Ile-Ife, Nigeria

Biomass fuel use and the exposure of children to particulate air pollution in southern Nepal

The exposure of children to air pollution in low resource settings is believed to be high because of the common use of biomass fuels for cooking. We used microenvironment sampling to estimate the respirable fraction of air pollution (particles with median diameter less than 4 μm) to which 7-9 year old children in southern Nepal were exposed. Sampling was conducted for a total 2649 h in 55 households, 8 schools and 8 outdoor locations of rural Dhanusha. We conducted gravimetric and photometric sampling in a subsample of the children in our study in the locations in which they usually resided (bedroom/living room, kitchen, veranda, in school and outdoors), repeated three times over one year. Using time activity information, a 24-hour time weighted average was modeled for all the children in the study. Approximately two-thirds of homes used biomass fuels, with the remainder mostly using gas. The exposure of children to air pollution was very high. The 24-hour time weighted average over the whole year was 168 μg/m(3). The non-kitchen related samples tended to show approximately double the concentration in winter than spring/autumn, and four times that of the monsoon season. There was no difference between the exposure of boys and girls. Air pollution in rural households was much higher than the World Health Organization and the National Ambient Air Quality Standards for Nepal recommendations for particulate exposure.

Health and household air pollution from solid fuel use: the need for improved exposure assessment

BACKGROUND

Nearly 3 billion people worldwide rely on solid fuel combustion to meet basic household energy needs. The resulting exposure to air pollution causes an estimated 4.5% of the global burden of disease. Large variability and a lack of resources for research and development have resulted in highly uncertain exposure estimates.

OBJECTIVE

We sought to identify research priorities for exposure assessment that will more accurately and precisely define exposure-response relationships of household air pollution necessary to inform future cleaner-burning cookstove dissemination programs.

DATA SOURCES

As part of an international workshop in May 2011, an expert group characterized the state of the science and developed recommendations for exposure assessment of household air pollution.

SYNTHESIS

The following priority research areas were identified to explain variability and reduce uncertainty of household air pollution exposure measurements: improved characterization of spatial and temporal variability for studies examining both short- and long-term health effects; development and validation of measurement technology and approaches to conduct complex exposure assessments in resource-limited settings with a large range of pollutant concentrations; and development and validation of biomarkers for estimating dose. Addressing these priority research areas, which will inherently require an increased allocation of resources for cookstove research, will lead to better characterization of exposure-response relationships.

CONCLUSIONS

Although the type and extent of exposure assessment will necessarily depend on the goal and design of the cookstove study, without improved understanding of exposure-response relationships, the level of air pollution reduction necessary to meet the health targets of cookstove interventions will remain uncertain.

Using PM2.5 concentrations to estimate the health burden from solid fuel combustion, with application to Irish and Scottish homes

BACKGROUND

This study estimates the potential population health burden from exposure to combustion-derived particulate air pollution in domestic settings in Ireland and Scotland.

METHODS

The study focused on solid fuel combustion used for heating and the use of gas for cooking. PM2.5 (particulate matter with an aerodynamic diameter < 2.5 μm) was used as the pollutant mixture indicator. Measured PM2.5 concentrations in homes using solid fuels were adjusted for other sources of PM2.5 by subtracting PM2.5 concentrations in homes using gas for cooking but not solid fuel heating. Health burden was estimated for exposure indoors 6 pm - midnight, or all day (24-hour), by combining estimated attributable annual PM2.5 exposures with (i) selected epidemiological functions linking PM2.5 with mortality and morbidity (involving some re-scaling from PM10 to PM2.5, and adjustments 'translating' from concentrations to exposures) and (ii) on the current population exposed and background rates of morbidity and mortality.

RESULTS

PM2.5 concentrations in coal and wood burning homes were similar to homes using gas for cooking, used here as a baseline (mean 24-hr PM2.5 concentrations 8.6 μg/m3) and so health impacts were not calculated. Concentrations of PM2.5 in homes using peat were higher (24-hr mean 15.6 μg/m3); however, health impacts were calculated for the exposed population in Ireland only; the proportion exposed in Scotland was very small. The assessment for winter evening exposure (estimated annual average increase of 2.11 μg/m3 over baseline) estimated 21 additional annual cases of all-cause mortality, 55 of chronic bronchitis, and 30,100 and 38,000 annual lower respiratory symptom days (including cough) and restricted activity days respectively.

CONCLUSION

New methods for estimating the potential health burden of combustion-generated pollution from solid fuels in Irish and Scottish homes are provided. The methodology involves several approximations and uncertainties but is consistent with a wider movement towards quantifying risks in PM2.5 irrespective of source. Results show an effect of indoor smoke from using peat (but not wood or coal) for heating and cooking; but they do not suggest that this is a major public health issue.

Household air pollution: a call for studies into biomarkers of exposure and predictors of respiratory disease

Household air pollution (HAP) from indoor burning of biomass or coal is a leading global cause of morbidity and mortality, mostly due to its association with acute respiratory infection in children and chronic respiratory and cardiovascular diseases in adults. Interventions that have significantly reduced exposure to HAP improve health outcomes and may reduce mortality. However, we lack robust, specific, and field-ready biomarkers to identify populations at greatest risk and to monitor the effectiveness of interventions. New scientific approaches are urgently needed to develop biomarkers of human exposure that accurately reflect exposure or effect. In this Perspective, we describe the global need for such biomarkers, the aims of biomarker development, and the state of development of tests that have the potential for rapid transition from laboratory bench to field use.

Are rocket mud stoves associated with lower indoor carbon monoxide and personal exposure in rural Kenya?

Household use of biomass fuels is a major source of indoor air pollution and poor health in developing countries. We conducted a cross-sectional investigation in rural Kenya to assess household air pollution in homes with traditional three-stone stove and rocket mud stove (RMS), a low-cost unvented wood stove. We conducted continuous measurements of kitchen carbon monoxide (CO) concentrations and personal exposures in 102 households. Median 48-h kitchen and personal CO concentrations were 7.3 and 6.5 ppm, respectively, for three-stone stoves, while the corresponding concentrations for RMS were 5.8 and 4.4 ppm. After adjusting for kitchen location, ventilation, socio-economic status, and fuel moisture content, the use of RMS was associated with 33% lower levels of kitchen CO [95% Confidence Interval (CI), 64.4-25.1%] and 42% lower levels of personal CO (95% CI, 66.0-1.1%) as compared to three-stone stoves. Differences in CO concentrations by stove type were more pronounced when averaged over the cooking periods, although they were attenuated after adjusting for confounding. In conclusion, RMS appear to lower kitchen and personal CO concentrations compared to the traditional three-stone stoves but overall, the CO concentrations remain high.

PRACTICAL IMPLICATIONS

The rocket mud stoves (RMS) were associated with lower CO concentrations compared to three-stone stoves. However, the difference in concentrations was modest and concentrations in both stove groups exceeded the WHO guideline of 7 μg/m(3) , suggesting the unvented RMSs on their own are unlikely to appreciably benefit health in this population. Greater air quality benefit could be realized if the stoves were complemented with behavior change, including education on extinguishing fire when not in use as well as fuel drying, and cooking in locations that are separate from the main house.

Urban vs. rural factors that affect adult asthma

In this review, our aim was to examine the influence of geographic variations on asthma prevalence and morbidity among adults, which is important for improving our understanding, identifying the burden, and for developing and implementing interventions aimed at reducing asthma morbidity. Asthma is a complex inflammatory disease of multifactorial origin, and is influenced by both environmental and genetic factors. The disparities in asthma prevalence and morbidity among the world's geographic locations are more likely to be associated with environmental exposures than genetic differences. In writing this article, we found that the indoor factors most consistently associated with asthma and asthma-related symptoms in adults included fuel combustion, mold growth, and environmental tobacco smoke in both urban and rural areas. Asthma and asthma-related symptoms occurred more frequently in urban than in rural areas, and that difference correlated with environmental risk exposures, SES, and healthcare access. Environmental risk factors to which urban adults were more frequently exposed than rural adults were dust mites,high levels of vehicle emissions, and a westernized lifestyle.Exposure to indoor biological contaminants in the urban environment is common.The main risk factors for developing asthma in urban areas are atopy and allergy to house dust mites, followed by allergens from animal dander. House dust mite exposure may potentially explain differences in diagnosis of asthma prevalence and morbidity among adults in urban vs. rural areas. In addition, the prevalence of asthma morbidity increases with urbanization. High levels of vehicle emissions,Western lifestyles and degree of urbanization itself, may affect outdoor and thereby indoor air quality. In urban areas, biomass fuels have been widely replaced by cleaner energy sources at home, such as gas and electricity, but in most developing countries, coal is still a major source of fuel for cooking and heating, particularly in winter. Moreover, exposure to ETS is common at home or at work in urban areas.There is evidence that asthma prevalence and morbidity is less common in rural than in urban areas. The possible reasons are that rural residents are exposed early in life to stables and to farm milk production, and such exposures are protective against developing asthma morbidity. Even so, asthma morbidity is disproportionately high among poor inner-city residents and in rural populations. A higher proportion of adult residents of nonmetropolitan areas were characterized as follows:aged 55 years or older, no previous college admission, low household income, no health insurance coverage, and could not see a doctor due to healthcare service availability, etc. In rural areas, biomass fuels meet more than 70% of the rural energy needs. Progress in adopting modern energy sources in rural areas has been slow. The most direct health impact comes from household energy use among the poor, who depend almost entirely on burning biomass fuels in simple cooking devices that are placed in inadequately ventilated spaces. Prospective studies are needed to assess the long-term effects of biomass smoke on lung health among adults in rural areas.Geographic differences in asthma susceptibility exist around the world. The reason for the differences in asthma prevalence in rural and urban areas may be due to the fact that populations have different lifestyles and cultures, as well as different environmental exposures and different genetic backgrounds. Identifying geographic disparities in asthma hospitalizations is critical to implementing prevention strategies,reducing morbidity, and improving healthcare financing for clinical asthma treatment. Although evidence shows that differences in the prevalence of asthma do exist between urban and rural dwellers in many parts of the world, including in developed countries, data are inadequate to evaluate the extent to which different pollutant exposures contribute to asthma morbidity and severity of asthma between urban and rural areas.