Chronic obstructive pulmonary disease burden, grades and erythrocytosis at a tertiary hospital in western Uganda

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide among people over 40 years of age, and erythrocytosis is one of the major complications associated with increased mortality among COPD patients. The study aimed to determine the proportion of COPD, associated factors, and the burden of erythrocytosis among COPD participants.

METHODS AND MATERIALS

A descriptive cross-sectional study design was used. A consecutive sampling technique was used to obtain study participants at the Fort Portal Regional Referral Hospital outpatient clinic. Focused history and physical examination were carried out to select eligible participants. Participants were screened using the COPD population screener for spirometry after consenting to participate. The study enrolled all adults at risk of having COPD based on the COPD population screener and able to undergo spirometry. Spirometry was carried out according to the Global Chronic Obstructive Lung Disease and European Respiratory Society guidelines, and haemoglobin concentration was measured.

RESULTS

One hundred eighty participants were enrolled in the study, most of whom were females. The modal and mean age of participants was 60 years with 139 (77.2%) females and primary as the highest education level 149(82.8%). The proportion of COPD was 25% (45) [95% CI 18.9 - 32] and highest among females (68.9%) and those aged 60 years and above (70%). The combined COPD assessment tool groups had a proportion of 55.6%, 37.8%, 4.4%, and 2.2% for groups A, B, C, and D, respectively. Age < 50 years was protective against COPD, while for every additional year of smoking, there was an associated 6.5% increased risk compared to the general population. Additionally, the proportion of erythrocytosis among COPD participants was 6.7%.

CONCLUSIONS AND RECOMMENDATIONS

There was a high proportion of COPD among study participants (25%), with a 6.7% proportion of erythrocytosis. We recommend a complete blood count for every patient in groups C and D of the ABCD COPD GOLD groups.

Disease burden and health risk to rural communities of northeastern India from indoor cooking-related exposure to parent, oxygenated and alkylated PAHs

Exposure to a total of 51 targeted and non-targeted polycyclic aromatic hydrocarbons (PAHs) and their oxygenated and alkylated derivatives associated with size-segregated aerosol was investigated in rural kitchens using liquefied petroleum gas (LPG), mixed biomass (MB) and firewood (FW) fuels in northeastern India. The averaged PM10-associated parent-, alkylated-, and oxygenated-PAHs concentrations increased notably from LPG (257, 54, and 116 ng m-3) to MB (838, 119, and 272 ng m-3) to FW-using kitchens (2762, 225, and 554 ng m-3), respectively. PAHs were preferentially associated with the PM1 fraction with contributions increasing from 80 % in LPG to 86 % in MB and 90 % in FW-using kitchens, which in turn was dominated by <0.25 μm particles (54-75 % of the total). A clear profile of enrichment of low-molecular weight PAHs in cleaner fuels (LPG) and a contrasting enrichment of high-molecular weight PAHs in biomass-based fuels was noted. The averaged internal dose of Benzo[a]pyrene equivalent was the lowest in the case of LPG (19 ng m-3), followed by MB (161 ng m-3) and the highest in FW users (782 ng m-3). Estimation of incremental lifetime cancer risk (ILCR) from PAH exposure revealed extremely high cancer risk in biomass users (factors of 8-40) compared to LPG. The potential years of life lost (PYLL) and PYLL rate averaged across kitchen categories was higher for lung cancer (PYLL: 10.55 ± 1.04 years; PYLL rate: 204 ± 426) compared to upper respiratory tract cancer (PYLL: 10.02 ± 0.05 years; PYLL rate: 4 ± 7), and the PYLL rates for biomass users were higher by factors of 9-56 as compared to LPG users. These findings stress the need for accelerated governmental intervention to ensure a quick transition from traditional biomass-based fuels to cleaner alternatives for the rural population of northeastern India.

Reduction of household air pollution through clean fuel intervention and recovery of cellular immune balance

BACKGROUND

We conducted a clean fuel intervention trial (Bangladesh Global Environmental and Occupational Health (GEOHealth) (NCT02824237) with liquefied petroleum gas (LPG) for 26 months among rural Bangladeshi women chronically exposed to household air pollution (HAP) from biomass fuel (BMF) use. We aimed to evaluate the effect of HAP reduction following LPG intervention on immune response outcome.

METHODS

We supplied LPG cook stove and refills in cylinder in 200 households for 26 months. We measured personal exposure to HAP [particulate matter 2.5 (PM2·5), black carbon (BC) and carbon monoxide (CO)] in 200 women (main cook) by personal monitors at pre- and post-intervention. Immune function was assessed before and after intervention, in blood collected within 2 weeks of HAP measurements. Primary endpoints included reduction in HAP, lymphocyte proliferation and oxidative stress response, and alterations in T and B cell proportions.

FINDINGS

Exclusive LPG use for 26 months resulted in significant reduction in PM2·5 (43.5%), BC (13%) and CO (48%) exposure in the women. For one unit decrease in BC, Treg cells and memory B cells increased by 7% and 34% respectively, in the peripheral circulation. One unit decrease in CO was significantly associated with increase in early B cells and plasmablasts by 66% and 5% respectively. For one unit decrease in BC, percent-dividing cells, proliferation and expansion indices increased by 2%, 0.4%, and 1%, respectively.

INTERPRETATION

Reduced personal exposure to HAP through clean fuel intervention was related to a return towards cellular immune balance.

Quantification of Indoor Respirable Suspended Particulate Matters (RSPM) and Asthma in Rural Children of Delhi-NCR

OBJECTIVES

To assess the exposure of indoor respirable suspended particulate matters (PM10, PM2.5, and PM1) and their association with asthma in children in a rural area of Delhi-NCR.

METHODS

It was a cross-sectional study. Fifty children with asthma from both biomass fuel users in group A and liquefied petroleum gas (LPG) fuel users in group B households were enrolled along with 50 healthy control subjects. The diagnosis of asthma was done as per the Global Initiative for Asthma (GINA), 2014. The 24-h levels of PM from all three groups of households were measured and compared. The level of PM with confounding factors like smoking and room occupancy was also compared between the groups.

RESULTS

The 24-h concentrations of PM10, PM2.5, and PM1 were found significantly higher in the households of group A and group B as opposed to group C (p < 0.001). The number of smokers with a mean pack year and a lack of an exhaust fan was highest in group A and lowest in group C, while diesel and kerosene machines were highest in group B. The PMs were highest in group A even with different confounding factor (p < 0.001). The level of all PM was higher in group B than in group C, despite the presence of both types of fuel in group C households. The level of all PM was highest during the cooking hour.

CONCLUSION

The level of 24-h PM was highest in group-A households. However, the level of PM was higher in group-B households than group C despite the presence of biomass fuel users in group C. This may be due to the higher number of smokers, poor room-occupancy and lack of exhaust fans.

The association between household biomass fuel use and leukocyte telomere length among toddlers in Bhaktapur, Nepal

BACKGROUND

Biomass fuels are still in use for cooking by many households in resource poor countries such as Nepal and is a major source of household air pollution (HAP). Chronic exposure to HAP has been shown to be associated with shorter telomere length in adults.

OBJECTIVES

To measure the association between exposure related to household biomass fuel in infancy and leukocyte telomere length (LTL) at 18-23 months of age among 497 children from Bhaktapur, Nepal.

METHODS

In a prospective cohort study design, we have collected information on household cooking fuel use and several clinical, anthropometric, demographic, and socioeconomic variables. We estimated the association between biomass fuel use and the relative LTL in multiple linear regression models.

RESULTS

Most of the families (78%) reported liquified petroleum gas (LPG) as the primary cooking fuel, and 18.7% used biomass. The mean relative (SD) LTL was 1.03 (0.19). Children living in households using biomass fuel had on average 0.09 (95% CI: 0.05 to 0.13) units shorter LTL than children in households with no biomass fuel use. The observed association was unaltered after adjusting for relevant confounders. The association between LTL and biomass use was strongest among children from households with ≤2 rooms and without separate kitchen.

SIGNIFICANCE

Exposure to biomass fuel use in early life might have consequences for longevity, and risk of chronic illnesses reflected in shortening of the telomeres. Our findings support the ongoing effort to reduce exposure to biomass fuel in low-resource settings.

IMPACT STATEMENTS

Biomass for cooking is a leading source of household air pollution in low and middle-income countries, contributing to many chronic diseases and premature deaths. Chronic exposure to biomass fuel through oxidative stress and inflammation has been associated with a shortening of the telomeres, a "biological marker" of longevity. This prospective cohort study describes the association between household biomass fuel use and leukocyte telomere length among 497 toddlers. Leukocyte telomere length was significantly shorter among children living in households with biomass fuel than in children from homes where mainly LPG was used for cooking.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov: NCT02272842, registered October 21, 2014, Universal Trial Number: U1111-1161-5187 (September 8, 2014).

Association of biomass fuel use with the risk of vision impairment among Chinese older adults: a cohort study

Cooking with biomass fuels has been reported to have adverse effects on health. This study aims to explore the association between cooking with biomass fuels and vision impairment among Chinese older adults aged 65 years and above. This cohort study drew on data from the 2011/2012 wave and the 2014 follow-up wave of the Chinese Longitudinal Healthy Longevity Survey. Participants' visual function was examined through a vision screening test. Exposure to indoor biomass fuels was self-reported. Cox proportional hazards models were applied to explore the relationship between biomass fuel use and vision impairment. Additionally, we compared the risk of vision impairment between participants who switched cooking fuel types and those who did not. Subgroup and interaction analyses were conducted to explore the potential effect modifiers. A total of 4711 participants were included in this study. During the follow-up, 1053 (22.35%) participants developed vision impairment. Cooking with biomass fuels increased the risk of vision impairment by 40% (hazard ratio [HR]: 1.40, 95% confidence interval [CI]: 1.21-1.61). Participants who switched from clean fuels to biomass fuels had a greater risk of vision impairment than persistent clean fuel users (HR: 1.44, 95% CI: 1.03-2.00). Greater effect estimates were found in participants who lived in eastern and central China and urban residents. Cooking with biomass fuels resulted in a greater risk of vision impairment among Chinese older adults. This risk also existed in those who changed their cooking fuels from clean fuels to biomass fuels. Further studies with an objective assessment of biomass fuel combustion are required to confirm our findings.

Impact of solid fuel usage on respiratory symptoms among reproductive aged women: a cross-sectional study in Sri Lanka

BACKGROUND

Worldwide, around 3 billion people rely on solid fuel for their daily energy needs. Household air pollution secondary to solid fuel burning is a major risk factor for respiratory mobility among vulnerable populations. This study aimed to investigate the respiratory symptoms associated with solid fuel usage, the level of kitchen fuel smoke exposure and its association with respiratory symptoms among reproductive-aged women in Sri Lanka, where most households exclusively use firewood as the primary cooking fuel.

METHODS

A descriptive cross-sectional study was conducted among 403 reproductive-aged women (15 to 49 years) in the Central Province, Sri Lanka. A structured interviewer-administered questionnaire was used to collect data, and an exposure assessment was done using a breath carbon monoxide monitor.

RESULTS

After adjusting for potential confounding factors by the logistic regression models, the odds ratios (OR) of the liquid petroleum gas-only users for at least one respiratory symptom relevant to cough (OR: 0.39; 95% confidence interval [CI]: 0.20-0.78), wheezing (OR: 0.47; 95% [CI]: 0.26-0.87), and dyspnea (OR: 0.44; 95% CI: 0.24-0.84) were significantly lower compared to firewood-only users. The mean of expired air carbon monoxide and estimated carboxyhemoglobin levels of liquid petroleum gas-only users (2.84 ± 2.85 ppm; 1.08 ± 0.46%) were significantly lower than those of firewood-only users (5.27 ± 4.64 ppm; 1.47 ± 0.74%).

CONCLUSIONS

The use of firewood increased the risk of respiratory symptoms among reproductive-aged women in Sri Lanka. Health education focused on positive behavioral changes and effective and efficient clean energy policies are recommended to mitigate the risk associated with solid fuel smoke exposure.

Quantitative assessment and mitigation measures of air pollution from crematoria in NCT of Delhi

The modernization of crematoria and replacement of existing fuel requirements for better air quality is a key challenge in view of the associated religious beliefs in India where conventional open pyre funeral practices are followed. Unlike developed nations, the lack of appropriate site selection criteria, combustion efficient crematorium oven designs, and pollution control devices at these facilities necessitates formulation of appropriate policy measures to reduce emissions. The existing practices do not address such localized sources that affects the micro air pollution patterns owing to their marginal contribution in the total air pollution load of the city. The present study is thus an attempt to estimate emissions from 51 cremation grounds identified in NCT of Delhi. The study considers both particulate and gaseous pollutants which are released due to burning of fuels like wood, CNG, and cow dung. It is estimated that cremation activities contributed 393 tons/year of PM_2.5, 142 tons/year of NO_x, 29 tons/year of SO₂, and 2686 tons/year of CO in year 2019. The maximum load was emitted from Central district as only Nigambodh Ghat crematoria receives on an average 60 bodies per day. Furthermore, air quality impact zone around crematoria has been demarcated using dispersion modelling considering crematorium with minimum and maximum number of bodies burnt in a day. The study also suggests control measures for reduction of pollution from cremation activities and delineates a buffer zone that could aid policymakers in establishing a site selection criterion to prevent the immediate population from likely exposure.

Effects of indoor air pollution on tribal community in rural India and health risk assessment due to domestic biomass burning: a realistic approach using the lung deposition model

Indoor air pollution from the combustion of biomass fuel and associated health risks is a critical issue in developing countries. Concentrations of PM2.5 and PM10 are measured in Birbhum, West Bengal, during 2017-2018. PM2.5-bound elemental concentrations of twelve metals are determined in rural kitchens. The results showed higher toxicological risks in BMF (1.15) than the LPG users (0.14). The risk of non-carcinogenic exposure related with dermal contact and ingestion was observed in the acceptable limits (HQ < 1) for all age groups, and the risk associated with inhalation exposure from Cr, Ni, As, and Mn exceeded the acceptable limit. Results also suggest that carcinogenic risks from ingestion and dermal contact are within the acceptable limit (1 × 10-4-1 × 10-6) except Cr and As which were found to exceed the range. The deposition flux (Dφ) for multiple metals in the head airway region, tracheobronchial region, and alveolar regions was found to be higher in teenagers as compared to other groups, whereas the value was lower in infants. Further, it was notified from the Dφ that the metals could pass through the head airways and harm the tracheobronchial tree and alveolar region, increasing the risk of human health.

Evaluation of indoor PM2.5 concentrations in a Native American Community: a pilot study

BACKGROUND

Indoor air pollution is associated with adverse health effects; however, few studies exist studying indoor air pollution on the Navajo Nation in the southwest U.S., a community with high rates of respiratory disease.

METHODS

Indoor PM_2.5 concentration was evaluated in 26 homes on the Navajo Nation using real-time PM_2.5 monitors. Household risk factors and daily activities were evaluated with three metrics of indoor PM_2.5: time-weighted average (TWA), 90th percentile of concentration, and daily minutes exceeding 100 μg/m³. A questionnaire and recall sheet were used to record baseline household characteristics and daily activities.

RESULTS

The median TWA, 90th percentile, and daily minutes exceeding 100 μg/m³ were 7.9 μg/m³, 14.0 μg/m³_, and 17 min, respectively. TWAs tended to be higher in autumn and in houses that used fuel the previous day. Other characteristics associated with elevated PM exposure in all metrics included overcrowded houses, nonmobile houses, and houses with current smokers, pets, and longer cooking time.

CONCLUSIONS

Some residents of the Navajo Nation have higher risk of exposure to indoor air pollution by Environmental Protection Agency (EPA) standards. Efforts to identify the causes and associations with adverse health effects are needed to ensure that exposure to risks and possible health impacts are mitigated.

Association of household air pollution with cellular and humoral immune responses among women in rural Bangladesh

Household air pollution (HAP) arising from combustion of biomass fuel (BMF) is a leading cause of morbidity and mortality in low-income countries. Air pollution may stimulate pro-inflammatory responses by activating diverse immune cells and cyto/chemokine expression, thereby contributing to diseases. We aimed to study cellular immune responses among women chronically exposed to HAP through use of BMF for domestic cooking. Among 200 healthy, non-smoking women in rural Bangladesh, we assessed exposure to HAP by measuring particulate matter 2.5 (PM2.5), black carbon (BC) and carbon monoxide (CO), through use of personal monitors RTI MicroPEM™ and Lascar CO logger respectively, for 48 h. Blood samples were collected following HAP exposure assessment and were analyzed for immunoprofiling by flow cytometry, plasma IgE by immunoassay analyzer and cyto/chemokine response from monocyte-derived-macrophages (MDM) and -dendritic cells (MDDC) by multiplex immunoassay. In multivariate linear regression model, a doubling of PM2.5 was associated with small increments in immature/early B cells (CD19+CD38+) and plasmablasts (CD19+CD38+CD27+). In contrast, a doubling of CO was associated with 1.20% reduction in CD19+ B lymphocytes (95% confidence interval (CI) = -2.36, -0.01). A doubling of PM2.5 and BC each was associated with 3.12% (95%CI = -5.85, -0.38) and 4.07% (95%CI = -7.96, -0.17) decrements in memory B cells (CD19+CD27+), respectively. Exposure to CO was associated with increased plasma IgE levels (beta(β) = 240.4, 95%CI = 3.06, 477.8). PM2.5 and CO exposure was associated with increased MDM production of CXCL10 (β = 12287, 95%CI = 1038, 23536) and CCL5 (β = 835.7, 95%CI = 95.5, 1576), respectively. Conversely, BC exposure was associated with reduction in MDDC-produced CCL5 (β = -3583, 95%CI = -6358, -807.8) and TNF-α (β = -15521, 95%CI = -28968, -2074). Our findings suggest that chronic HAP exposure through BMF use adversely affects proportions of B lymphocytes, particularly memory B cells, plasma IgE levels and functions of antigen presenting cells in rural women.

Association of using biomass fuel for cooking with depression and anxiety symptoms in older Chinese adults

BACKGROUNDS

Household air pollution exposure is a crucial public concern and have the potential to seriously affect human health. Using biomass fuels for cooking is the main contributor to household air pollution. However, current evidence linked between cooking with biomass fuels and mental health remains limited.

OBJECTIVES

To explore whether cooking with biomass fuels is associated with depression and anxiety symptoms among older adults in China.

METHODS

We obtained data from Chinese Longitudinal Healthy Longevity Survey (CLHLS). Depressive and anxiety symptoms were assessed using the 10-item Center for Epidemiologic Studies Depression Scale (CES-D-10) and the 7-item Generalized Anxiety Disorder Scale (GAD-7), respectively. Primary cooking fuel type was self-reported. We used logistic regression and linear regression to evaluate the effects of cooking with biomass fuels on depression and anxiety.

RESULTS

A total of 13,361 participants aged 65 years and older (mean age, 84.2 ± 11.5 years) were included in the presented study. A positive association was found between cooking with biomass fuels and both depression symptoms (adjusted odds ratio 1.23, 95% CI 1.03 to 1.47) and anxiety symptoms (adjusted odds ratio 1.31, 95% CI 1.02 to 1.68). Biomass fuel users had a higher depression scores (0.33, 95% CI 0.03 to 0.61) and a higher anxiety scores (0.20, 95% CI 0.02 to 0.38) compared to clean fuel users. We found no significant interactions between participant characteristics and biomass fuel use on either depression or anxiety symptoms.

CONCLUSIONS

Cooking with biomass fuels was associated with depression and anxiety symptoms in order adults. Further large prospective cohort studies are warranted to confirm this association.

Factors predisposing women and children to indoor air pollution in rural villages, Western Kenya

BACKGROUND

Indoor air pollution (IAP) remains a major global public health hazard more so in developing countries where use of fossil fuels is still very common. However, despite the popularity of kerosene and fuelwood as energy sources among many households in the Sub-Saharan Africa, little is known about their health effects and the predisposing factors particularly on those with direct exposure. This study sought to relate indoor air pollution exposure to self-reported prevalence of respiratory outcomes including (sputum production, congestion, breathing difficulties, eye problems, fatigue, and headaches and wheezing) among women and children of Trans Nzoia County, in the rural villages of western Kenya.

METHODS

In this cross-sectional survey, simple random technique was used to select 251 households from 14 villages. Households were the sampling units, while the woman of the household with/or in custody of a child aged less than 5 years old were the unit of analysis. A total of 251 women with/or in custody of a child aged less than 5 years old took part in the study. A structured questionnaire was used to collect information on cause and effects of IAP among women and children. Data was analyzed descriptively and inferentially. We used Poisson generalized linear models with IAP symptoms and indoor cooking as dependent variables and household profiles and other socio-demographics as independent variables to identify the factors that affect health outcome.

RESULTS

Mean age of respondents was 36.49 years, (95% CI [35.5, 37.5]). Most (64.5%) houses were semi-permanent, with 58.6% having an average kitchen size (5.6 m2). Wood and kerosene were the most preferred fuel types for cooking (96.8%) and lighting (97.4%), respectively. Smoke from the wood was identified as the dominant (96.8%) source of IAP. Most women (92.0%) and children (95.4%) had coughs of varying intensities during the year, while 31.5% of the women reported wheezing. About 98% of them experienced fatigued and headaches. Use of wood fuel was associated with increased coughing (p = 0.03), phlegm (p = 0.02), wheezing (p = 0.04), eye problems (p = 0.03) and headaches (p = 0.01) among women and children in the previous 24 h. Education level, ventilation, main fuel source used in 24 h, indoor cooking and house type were significantly associated with IAP health effects (p ≤ 0.05).

CONCLUSIONS

Supporting the impoverished households and increasing their level of awareness on health-effects of IAP occasioned by use of biomass fuel while cooking indoors may be the first step in implementing a programme aimed at reducing exposure among rural households in Trans Nzoia County, in rural parts of Western Kenya.

Emission characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans from industrial combustion of biomass fuels

Although biomass fuel has always been regarded as a source of sustainable energy, it potentially emits polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). This study investigated PCDD/F emissions from industrial boilers fired with three types of biomass fuel (i.e., bagasse, coffee residue, and biomass pellets) via stack sampling and laboratory analysis. The measured mass concentrations of PCDD/Fs varied among the boilers from 0.0491 to 12.7 ng Nm^-3 (11% O₂), with the calculated average international toxic equivalent quantity (I-TEQ) from 0.00195 to 1.71 ng I-TEQ Nm^-3 (11% O₂). Some of them were beyond the limit value for municipal waste incineration. 2,3,4,7,8-PeCDF could be used as a good indicator of dioxin-induced toxicity of stack flue gases from biomass-fired boilers. The PCDFs/PCDDs ratios were more than 1, likely indicating the formation of dioxins in the boilers favored by de novo synthesis. The emission factor (EF) of total PCDD/Fs averaged 5.35 ng I-TEQ kg^-1 air-dry biomass (equivalent to 39.0 ng kg^-1 air-dry biomass). Specifically, the mean EF was 6.94 ng I-TEQ kg^-1 (52.6 ng kg^-1) for biomass-pellet-fired boiler, 11.8 ng I-TEQ kg^-1 (74.6 ng kg^-1) for coffee-residue -fired boiler, and 0.0277 ng I-TEQ kg^-1 (0.489 ng kg^-1) for bagasse-fired boilers. The annual PCDD/F emission was estimated to be 208 g I-TEQ in 2020 in China, accounting for approximately 2% of the total national annual emission of PCDD/Fs. The results can be used to develop PCDD/Fs emission inventories and offer valuable insights to authorities regarding utilizing biomass in industry in the future.

Determinants of asthma in Ethiopia: age and sex matched case control study with special reference to household fuel exposure and housing characteristics

BACKGROUND

Asthma is a chronic inflammatory disorder characterized by airway obstruction and hyper-responsiveness. Studies suggest that household fuel exposure and housing characteristics are associated with air way related allergy. But there remains to be a considerable uncertainty about whether that reflects an association with asthma. This study endeavored to bridge the gap by identifying factors associated with asthma, with special reference to household fuel exposure and housing characteristics in selected public hospitals in Addis Ababa, Ethiopia.

METHODS

We conducted a hospital-based matched case-control study. A total of 483 study participants were selected from two Ethiopian referral hospitals using a sequential sampling technique, with 161 cases and 322 controls. Standard questionnaire from the European Community Respiratory Health Survey II (ECRHS II) and the American Thoracic Society Division of Lung Disease (ATS-DLD-78) were used to collect household related data. Conditional logistic regression model was applied to identify the determinants of asthma. Both crude and adjusted odds ratios with 95% confidence interval (CI) were used to identify predictors of asthma.

RESULTS

The response rate for both cases and controls was 99.17%. The odds of developing asthma was about four times higher among those who used agricultural residues for cooking (AOR: 3.81, 95% CI: 1.05, 13.79)., about five times higher among those who used wood for cooking (AOR: 4.95, 95% CI: 2.1, 11.69), nearly five times higher among those who had family history of asthma (AOR: 4.72, 95% CI: 1.54, 14.45), just over six times higher among those who smoke tobacco (AOR: 6.16, 95% CI: 1.31, 29.09) and over ten times higher among those who do not practice door opening, while cooking (AOR: 10.25, 95% CI: 3.97, 26.49).

CONCLUSION

Family history of asthma, tobacco smoking, use of solid fuels including, woods and agricultural residues were associated with development of asthma. To reduce the risk of asthma, people should practice door opening, while cooking, and must avoid using wood and agricultural residues for cooking and should also refrain from tobacco smoking.

Cooking with biomass fuels increased the risk for cognitive impairment and cognitive decline among the oldest-old Chinese adults (2011-2018): A prospective cohort study

BACKGROUNDS

While the pernicious effects of outdoor air pollution on cognitive ability have been previously examined, evidence regarding household air pollution is scarce.

METHODS

Using data from the Chinese Longitudinal Healthy Longevity Survey, we explored the relationship between cooking with biomass fuel and cognitive impairment and cognitive decline using a Cox proportional hazards model. We further assessed the correlation of biomass fuels and cognitive score using a generalized estimating equation. Cognitive ability was measured based on the Chinese version of the Mini-Mental State Examination (MMSE) and cognitive impairment was defined as MMSE < 24 points and cognitive decline was defined as a reduction of MMSE ≥ 3 points. On follow-up, we investigated the effect of switch-cooking combustibles on cognitive ability.

RESULTS

The mean (SD) age of 4161 participants was 81.7 (10.0) years old. The reported cooking with biomass fuels was correlated with an elevated risk of cognitive impairment (hazard ratio (HR): 1.19, 95% confidence interval (CI): 1.04, 1.37) and cognitive decline (HR: 1.18, 95% CI: 1.04, 1.33). Besides, cooking with biomass fuels was related to a decrease in cognitive score (β: -0.43, 95% CI: -0.73, -0.14). In comparison to persistent biomass fuel users, participants who reported changing their primary cooking fuels from biomass to clean fuels exhibited a reduced risk of cognitive impairment (HR: 0.68, 95% CI: 0.57, 0.82) and cognitive decline (HR: 0.66, 95% CI: 0.56, 0.76) and a higher cognitive score (β: 0.72, 95% CI: 0.17, 1.26). Cooking without ventilated cookstoves was associated with a higher risk of cognitive impairment (HR: 1.31, 95% CI: 1.10, 1.58) and cognitive decline (HR: 1.18, 95% CI: 1.02, 1.38), regardless of types of cooking fuels. Interaction and stratified analyses showed relatively poor cognitive ability in participants who engaged in irregular exercise or were not living with family members.

CONCLUSIONS

Cooking with biomass fuels was correlated with a higher risk of cognitive impairment and cognitive decline. Among the oldest-old population, this risk may, however, be lower for those changing their primary cooking fuels from biomass to clean fuels.

Risk of anaemia among women engaged in biomass-based fish smoking as their primary livelihood in the central region of Ghana: a comparative cross-sectional study

BACKGROUND

Fish smoking using biomass fuel is an important livelihood for women living in the coastal regions of Ghana and may contribute to anaemia risk. We assessed whether women who smoke fish as their primary livelihood are at increased risk of anaemia compared to women in other livelihoods in the Central Region of Ghana.

METHODS

We conducted a comparative cross-sectional study of 330 randomly selected adult women (18-49 years) whose primary livelihood was either fish smoking (FSL) involving the burning of biomass fuel (n = 175) or other livelihoods (OL) not involving burning of firewood (n = 155). Data on participants' recent diet were collected from a single, quantitative 24-h dietary recall and qualitative 7-day food frequency questionnaire of animal-source food (ASF) consumption. We further assessed participants' haemoglobin concentration using the Urit 12 Hemocue system. We compared total iron intakes, the proportion of dietary iron from animal and plant sources, mean haemoglobin concentrations, and anaemia prevalence between FSL and OL women.

RESULTS

Fish was the most frequently consumed ASF by both groups of women. Although OL women consumed more diverse ASFs in the past week compared with the FSL women (3.4 ± 1.2 vs. 2.7 ± 1.3; p < 0.001), the contribution of ASFs to total iron intake in the past day was greater for the FSL women (49.5% vs. 44.0%; p = 0.030). Estimated total dietary iron intake in the past day was generally low (5.2 ± 4.7 mg) and did not differ by group. The unadjusted prevalence of anaemia was 32 and 27.1% among the FSL and OL women, respectively (p = 0.33). After covariates adjustment, the FSL women had statistically higher anaemia prevalence (36.4% vs. 20.5%; p = 0.032) and 80% greater risk of being anemic (RR: 1.8; 95% CI: 1.1, 3.0) than the OL women.

CONCLUSION

Women who use biomass fuel to smoke fish as their primary livelihood had an increased risk of anaemia. Furthermore, the average 24-h dietary iron intake among both the FSL and OL women was below their daily iron requirement. Interventions to enhance women's dietary iron intake and reduce their livelihood related biomass smoke exposure may be warranted in this population.

Exposure to biomass fuel is associated with high blood pressure and fasting blood glucose impairment in females in southern rural China

OBJECTIVES

We sought to investigate the association between household exposure to biomass fuel and metabolic syndrome (MetS) and its components including blood pressure, triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), fasting blood glucose (FBG) and waist circumference among females in southern rural China.

METHODS

We surveyed 1664 residents in the Chronic Disease and Risk Factors Surveillance, conducted in 14 districts of Guangdong province. We recorded the use of biomass fuel, MetS and its components, and other covariates by using a structured questionnaire. Logistic regression model and multivariate linear regression model were adopted for analysis.

RESULTS

Exposure to biomass fuel was significantly associated with an increase of systolic blood pressure (SBP) (β: 2.15, 95% confidence interval: 0.13 to 4.17) and FBG (β: 0.19, 95% confidence interval: 0.01 to 0.37) in the adjusted and unadjusted models (all P < 0.05). Among participants with exposure to biomass fuel, being overweight or obese was associated with an increased risk of having hypertension (odds ratio: 3.19, 95% confidence interval: 2.13 to 4.76) and higher FBG levels (odds ratio: 2.10, 95% confidence interval: 1.46 to 3.02). Exposure to biomass fuel was significantly associated with a decrease of the prevalence of central obesity (P < 0.05). However, exposure to biomass fuel was not associated with MetS, diastolic blood pressure and TG (all P > 0.05).

CONCLUSIONS

Exposure to biomass fuel is associated with an increase in blood pressure and FBG levels, but not MetS per se. Efforts should be made to protect females in southern rural China from the adverse effects associated with biomass fuel pollution.

Biomass fuel use and acute respiratory infection among children younger than 5 years in Ethiopia: a systematic review and meta-analysis

OBJECTIVES

The objective of this study was to estimate the magnitude of acute respiratory infection (ARI) among children younger than 5 years (under-five children) and its association with biomass fuel use for domestic purposes and other behavioural and housing characteristics in Ethiopia.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

PubMed, Google Scholar, MEDLINE and the Cochrane Library were systematically searched (using the Preferred Items for Systematic Review and Meta-analysis guideline) for studies that reported an association between biomass fuel use for domestic purposes and ARI. Grey literature and other sources of unpublished information, which were subjected to the same extraction methods and quality appraisal as published studies, were also identified. A meta-analysis was performed to combine the quantitative measures from eligible individual studies into a summary estimate. Quality assessment was conducted using the modified Newcastle-Ottawa Scale quality assessment tool for cross-sectional and case-control studies. Funnel and Doi plots were used to detect potential publication bias. Statistical analyses were performed using Comprehensive Meta-Analysis and MetaXL, version 5.3, software.

RESULTS

A total of 21 (18 cross-sectional and 3 case-control) eligible studies with their combined 30,013 participants were reviewed. The overall pooled prevalence of ARI among under-five children in households where biomass fuel was the main source of energy was estimated to be 22% (95% confidence interval [CI]: 17-29). In the subgroup analysis by area of residence, the highest prevalence was found in urban regions 26% (95% CI: 24-28). Based on the preceding 2 weeks before the interview, a significant association was found between biomass fuel use and ARI (odds ratio [OR] = 2.6, 95% CI: 2.05-3.30). In addition to biomass fuel use, being female (OR = 1.57, 95% CI: 1.06-2.33), absence of a window in the kitchen (OR = 2.89, 95% CI: 2.11-3.96), being carried on the back or in lap during cooking (OR = 2.76, 95% CI: 1.96-3.89) and non-separated kitchen from the main house (OR = 1.99, 95% CI: 1.49-2.68) were associated with ARI.

CONCLUSIONS

Based on the results of this review, ARI among under-five children remains high. The present study also revealed that ARI is associated with biomass fuel use, child's gender, absence of a window in the kitchen, non-separated kitchen and carrying the child while cooking. Improved solid fuel stoves, advanced combustion designs, windows or chimneys, separating the kitchen from the main house are all measures required to reduce ARI in under-five children.

SYSTEMATIC REVIEW REGISTRATION

The review has been registered with PROSPERO (registration number CRD42020181372).

Association between biomass fuel use and the risk of cognitive impairment among older populations in China: a population-based cohort study

BACKGROUND

Cohort studies on the impact of biomass fuel use for cooking on cognitive impairment among older population are still lacking in China and elsewhere. The aim of this study was to examine whether biomass fuel use for cooking is associated with cognitive impairment in Chinese adults aged 65 years or older.

METHODS

The prospective population-based cohort study of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) included participants aged 65 years or older in 2014 who were followed-up until 2018 in 23 provinces in China. The Mini-Mental State Examination (MMSE) was used to assess cognitive function, and cognitive impairment was defined as total MMSE scores less than 18. The association between biomass fuel use and cognitive impairment was evaluated using the Cox proportional hazards model.

RESULTS

Of the 4145 participants included at baseline, participants who reported that they used biomass fuel for cooking (40.43%; IR: 3.11 versus 2.77 per 100 person-years; aHR: 1.27, 95% CI: 1.02-1.58) had a higher risk of cognitive impairment compared with participants who used clean fuels (53.75%). A stratified analyses showed greater effect estimates of cognitive impairment in the older people that lived in the rural areas (aHR: 1.444, 95% CI: 1.08-3.90) and never smoked (aHR: 1.33, 95% CI: 1.04-1.71).

CONCLUSIONS

These findings demonstrated that biomass fuel used for cooking was associated with cognitive impairment, as defined by MMSE, in a population-based study of elderly in China. To prevent cognitive impairment, the structure of cooking fuels requires improvements.

Cost-benefit analysis for recycling of agricultural wastes in Taiwan

Agricultural waste can be recycled in different ways. Cost-effectiveness is important information for investment decision-making of enterprises and policy-making of government to choose a profitable way to recycle agricultural waste. Therefore, this paper aims to present a cost-benefit analysis to assess and compare the cost-effectiveness between feasible recycling methods, and further propose cost-effective ways for recycling agricultural waste in Taiwan. Three recycling types of agricultural wastes, namely, composting, biogas power generation and biomass fuel are selected for cost-benefit analysis based on related regulations and policy supports of agricultural waste management in Taiwan. Primary data collected by sampling surveys conducted in 2018 supplemented by secondary data from national statistics are used for this study. Study results show that all three recycling types of agricultural wastes discussed in this study are profitable under corresponding economic conditions in 2018 with benefit/cost ratio greater than 1 and positive net present value; as expected, the cost-effectiveness of agricultural waste recycling varies depending on the recycling types, composition of input materials, and economic scales. Mixing chicken manure with other agricultural wastes for composting and using rice straw to make biomass fuel rods are estimated to have higher cost-effectiveness; livestock farms with small farming scale have relatively low biogas energy recovery efficiency; the cost-effectiveness of biogas power generation highly depends on fixed-in tariffs (FITs). Results imply that policy support for establishing co-processing centers of agricultural waste and differentiated FITs would be good measures to stimulate recycling efficiency of agricultural waste in Taiwan.

Assessing the prevalence trend of childhood pneumonia associated with indoor air pollution in Pakistan

The indoor air pollution (IAP) is one of the leading risk factors of childhood pneumonia in developing countries. This study makes the first attempt to examine the prevalence trend of pneumonia among under-five children in Pakistan in association with IAP-related factors, using bivariate and multivariate statistical methods. Three waves of Pakistan Demographic Health Survey for 2006-2007, 2012-2013, and 2017-2018 were used. Our study findings showed a steady decline in the prevalence of pneumonia synchronized with the decreased use of polluting fuel during the last decade (2006-2017). In bivariate regression, odd ratios of childhood pneumonia were 1.27 and 1.21 times higher in overcrowded houses in 2006-2007 and 2012-2013, respectively, and 1.25 times higher in families relying on biomass for cooking in 2017-2018. In the multivariate model, polluting fuel and overcrowded homes had higher adjusted odd ratios of pneumonia in all survey years, and children age 37-48 months, older mothers, and large birth sized children had lower AOR of pneumonia in 2006-2007 and 2012-2013. Countrywide promotion of IAP mitigation measures such as sponsoring cleaner fuels, separate place for cooking, and lessening home overcrowding may play a vital role in alleviating the prevalence of childhood pneumonia.

Chronic exposure to ambient particulate matter induces gut microbial dysbiosis in a rat COPD model

Background

The role of the microbiota in the pathogenesis of chronic obstructive pulmonary disease (COPD) following exposure to ambient particulate matter (PM) is largely unknown.

Methods

Fifty-four male Sprague-Dawley rats were exposed to clean air, biomass fuel (BMF), or motor vehicle exhaust (MVE) for 4, 12, and 24 weeks. We performed pulmonary inflammation evaluation, morphometric measurements, and lung function analysis in rat lung at three different times points during exposure. Lung and gut microbial composition was assessed by 16S rRNA pyrosequencing. Serum lipopolysaccharide levels were measured and short-chain fatty acids in colon contents were quantified.

Results

After a 24-week PM exposure, rats exhibited pulmonary inflammation and pathological changes characteristic of COPD. The control and PM exposure (BMF and MVE) groups showed similar microbial diversity and composition in rat lung. However, the gut microbiota after 24 weeks PM exposure was characterized by decreased microbial richness and diversity, distinct overall microbial composition, lower levels of short-chain fatty acids, and higher serum lipopolysaccharide.

Conclusion

Chronic exposure to ambient particulate matter induces gut microbial dysbiosis and metabolite shifts in a rat model of chronic obstructive pulmonary disease.

Hydrothermal carbonization of waste biomass: An experimental comparison between process layouts

This paper contributes to the knowledge on waste biomass conversion processes occurring in the presence of hot compressed water. The experimental procedure detailed herein assesses different process schemes based on the low-temperature reaction known as hydrothermal carbonization. The performances of two lab-scale reactor configurations, with and without a downstream flash expansion step, were evaluated and compared. Each setup was tested with six different types of waste biomass. Fir, beech, and olive prunings are representative of lignocellulosic raw materials, while potato, pea, and carrot are representative of non-lignocellulosic wastes from processing in the local agro-food industry. The batch reactions (200 °C, water/solid = 7/1) were carried out for up to 120 min. The hydrochars were characterized by elemental composition, humidity, heating value, and mass and energy yields. The extent of difference between the results obtained for the two procedures varied significantly with the material treated. At a residence time of 30 min, the solid yields increased due to expansion, ranging from 10 to 36% for lignocellulosic material and 50 to 220% for agro-food industry scraps. The downstream flash expansion step causes an increase of the solid yields, especially for hydrochars from lignocellulosic materials, leading to higher energy recovered compared to the configuration without expansion. Lignocellulosic and agro-food wastes behaved dissimilarly, likely because of different hydrothermal reaction pathways. The additional expansion step can considerably increase the efficiency of energy recovery in full-scale plants, the extent of which depends on the biomass waste substrate used.

Indoor air pollution from cook-stoves during Injera baking in Ethiopia, exposure, and health risk assessment

This study was undertaken to assess indoor air pollution and potential exposure to particulate matters (PMs-PM₁, PM_2.5, PM₄, PM₇, PM₁₀), and total suspended particles [TSP] and total volatile organic compounds [TVOCs] during baking of Ethiopian traditional staple food, Injera using different types of stoves at Addis Ababa, Ethiopia. The geometric mean (GOM) of PMs pollutant using clean, improved, and traditional stoves were ranged 10.8-235, 23.6-462, and 36.4-591 µg/m³, respectively. The GOM of TVOCs in the wet and dry season using the clean, improved, and traditional stoves were 1,553, 2,234, 4,421, and 845, 1,214, and 2,662 µg/m³, respectively. The health risk of an exposed person to PM_2.5, PM₁₀, and TSP during baking of Injera was characterized and the results showed only baking of Injera using any of the stove types does not cause health problems to the baker. However, the percent contribution to the total chronic intake is high up to 38%.

Comparative study on respiratory function among rural women using biomass fuel and non-biomass fuel: evidence of a cross-sectional survey in Bangladesh

Respiratory diseases' mortality and morbidity have been a major public health burden primarily attributed to widespread exposure to indoor and outdoor pollutants in the environment. The study conducted among 510 Bangladeshi women residing in the northeastern zone of the Sylhet division from semi-urban and rural settings to compare the biomass fuel users (N = 255) with the non-biomass users (N = 255). It has been observed that all the symptoms had a higher prevalence among the women who were exposed to biomass fuel compared with those exposed to clean gas fuel. Women exposed to biomass group reported frequent cough and phlegm production episodes during a 3-month timeline before the survey period which was found statistically higher (p < 0.001) compared with that of the clean gas fuel group. Moreover, the use of biomass fuel has been associated with a significant decrease in forced expiratory volume in one second (FEV₁), forced vital capacity (FVC), and peak expiratory flow rate (PEFR). Appropriate strategies from stakeholders and government authorities in disseminating health hazards from biomass fuel along with supporting the community by providing alternative energy sources for cooking can largely impact people's lives.

Association of biomass fuel use with reduced body weight of adult Ghanaian women

The association of biomass fuel use with body weight has never been investigated. We therefore examined the effect of biomass fuel use on body weight of adult Ghanaian women. Data from the 2014 Ghana Demographic and Health Survey, a nationally representative population-based survey was analysed for this study. A total of 4751 women who had anthropometric (height and weight) data qualified for inclusion in this study. In linear regression modelling, charcoal use resulted in 3.08 kg (95% CI: 2.04, 4.12) and 0.81 kg/m² (95%CI: 0.29, 1.33) reduction in weight and body mass index (BMI), respectively, compared to clean fuel (electricity, liquefied petroleum gas and natural gas) use. Use of wood resulted in much higher reduction in weight and BMI. In modified Poisson regression, charcoal users had 19% (Adjusted Prevalence Ratio [aPR] = 0.81; 95%CI: 0.71, 0.92) and 29% (aPR = 0.71; 95%CI: 0.61, 0.83) decreased risk of overweight and obesity, respectively, compared to clean fuel users. Wood users had much higher decreased risk of overweight and obesity. In conclusion, biomass fuel use was associated with reduced body weight and BMI of Ghanaian women and is the first report on the relationship. However, it is important that our findings are confirmed and the biological mechanisms elucidated through rigorous study designs.

Association between biomass fuel use and risk of hypertension among Chinese older people: A cohort study

BACKGROUNDS

Previous studies linking biomass fuel use to hypertension have been inconsistent. We investigated the association between biomass fuel use and the risk of hypertension and blood pressure measures in older Chinese people.

METHODS

The prospective cohort study of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) included participants aged 65 years and older in 2011/2012 who were followed up until 2014 in 23 provinces in China. We explored the association between biomass fuel use and hypertension using the Cox proportional hazards model and examined the relationship of biomass fuel use with blood pressure measures using the generalized estimating equation. Additionally, we examined the effect of switching cooking fuels on hypertension during the follow-up.

RESULTS

Among 3754 participants who were without hypertension at baseline, the mean age was 86 years old, and 47.5% of participants were men. Reported use of biomass fuel for cooking (50.2%) was associated with a higher risk of hypertension (incidence rate (IR) per 100 person-years: 13.15 versus 12.99, hazard ratio (HR) = 1.15, 95% confidence interval (CI) = 1.01-1.31). Biomass fuel use was related to systolic blood pressure (SBP) (β 1.10 mmHg, 95% CI: 0.48-1.72), diastolic blood pressure (DBP) (β 1.02 mmHg, 95% CI: 0.61-1.43) and mean arterial pressure (MAP) (β 1.03 mmHg, 95% CI: 0.63-1.43) elevation. Compared with persistent clean fuel users, participants who reported switching from clean to biomass fuels for cooking had a noticeably higher risk of hypertension (IR per 100 person-years: 14.27 versus 12.81, HR 1.49, 95% CI: 1.16-1.90) and higher SBP (3.71 mmHg), DBP (2.44 mmHg) and MAP (2.86 mmHg). Interaction and stratified analyses showed greater effect estimates of SBP and MAP in the oldest oldpeople (≥85).

CONCLUSIONS

The use of biomass fuel for cooking was associated with greater hypertension risk, and the risk may be higher among those who switched from clean fuels to biomass fuels in the Chinese elderly population. Biomass fuel use was associated with a statistically significant but small absolute increase in blood pressure measures.

Cooking with biomass fuel and cardiovascular disease: a cross-sectional study among rural villagers in Phitsanulok, Thailand

Background: Burning biomass fuel is a major source of indoor air pollution; about 40% of Thai people still use biomass for cooking. There is increasing evidence of the association between biomass smoke exposure and serious health effects including cardiovascular disease. The object of this cross-sectional study was to investigate the association between biomass use for household cooking and cardiovascular outcome, including coronary heart disease, hypertension, high cholesterol, diabetes mellitus, and stroke among rural villagers in Phitsanulok, Thailand. 

Methods: Data from 1078 households were collected using a face-to-face interview questionnaire. In each household, data on cardiovascular disease, cooking practices, and cooking fuel, types of fuel they normally used for cooking, were collected.

Results: After being adjusted for gender, age, cigarette smoke, secondhand smoke, and exposure to other sources of air pollution, it was found that the family members of cooks using biomass fuel were at risk of coronary heart disease (CHD; OR=4.35; 95%CI 0.10–18.97), hypertension (OR=1.61; 95%CI 1.10–2.35), high cholesterol (HC; OR=2.74; 95%CI 1.66–4.53), and diabetes (OR=1.88; 95%CI 1.03–3.46). Compared to LPG use, using wood was associated with stroke (OR=7.64; 95%CI 1.18–49.61), and using charcoal was associated with HC (OR=1.52; 95%CI 1.04–2.24). Compared to never user, household cooks who sometimes use charcoal had an increased risk of hypertension (OR=2.04; 95%CI 1.32–3.15), HC (OR=2.61; 95%CI 1.63–4.18), and diabetes (OR=2.09; 95%CI 1.17–3.73); and cooks who often use charcoal had an elevated risk of stroke (OR=3.17; 95%CI 1.04–9.71), and HC (OR=1.52; 95%CI 1.02–2.27) to their family members.

Conclusions: The study results were consistent with those found in studies from other parts of the world, and supports that exposure to biomass smoke increase cardiovascular diseases. The issue should receive more attention, and promotion of clean fuel use is a prominent action.

Cardiovascular Effects of Indoor Air Pollution from Solid Fuel: Relevance to Sub-Saharan Africa

PURPOSE OF REVIEW

This research aims to summarize evidence on the cardiovascular effects of indoor air pollution (IAP) from solid fuel and identify areas for research and policy for low- and middle-income countries.

RECENT FINDINGS

IAP affects people from low socioeconomic status in Latin America, Asia, and Africa, who depend upon biomass as a fuel for cooking, heating, and lighting. In these settings, IAP disproportionately affects women, children, the elderly, and people with cardiopulmonary disease. The health effects of IAP include acute respiratory infections, chronic obstructive pulmonary disease, pneumoconiosis, cataract and blindness, pulmonary tuberculosis, adverse effects to pregnancy, cancer, and cardiovascular and cerebrovascular disease. New methods for assessing individual IAP exposure, exposing pathways of IAP-related cardiovascular disease, and performing qualitative research focusing on population preferences regarding strategies to reduce IAP exposure have been the most important developments in tackling the burden of IAP. Unfortunately, major disparities exist regarding research into the cardiovascular effects of IAP, with only few studies coming from sub-Saharan Africa, despite this region having the highest proportion of households using solid fuels. Premature cardiovascular deaths and disability can be averted in low-middle income countries by addressing biomass fuel usage by the most disadvantaged settings. While research is needed to uncover the mechanisms involved in cardiovascular outcomes linked to IAP, immediate action is needed to educate the most affected populations on IAP health hazards and to reduce their exposure to this environmental risk through promoting improved housing and better ventilation, as well as increasing access to affordable clean cooking energy.

Lack of an Association Between Household Air Pollution Exposure and Previous Pulmonary Tuberculosis

CONTEXT

Observational studies investigating household air pollution (HAP) exposure to biomass fuel smoke as a risk factor for pulmonary tuberculosis have reported inconsistent results.

OBJECTIVE

To evaluate the association between HAP exposure and the prevalence of self-reported previous pulmonary tuberculosis.

DESIGN

We analyzed pooled data including 12,592 individuals from five population-based studies conducted in Latin America, East Africa, and Southeast Asia from 2010 to 2015. We used multivariable logistic regression to model the association between HAP exposure and self-reported previous pulmonary tuberculosis adjusted for age, sex, tobacco smoking, body mass index, secondary education, site and country of residence.

RESULTS

Mean age was 54.6 years (range of mean age across settings 43.8-59.6 years) and 48.6% were women (range of % women 38.3-54.5%). The proportion of participants reporting HAP exposure was 38.8% (range in % HAP exposure 0.48-99.4%). Prevalence of previous pulmonary tuberculosis was 2.7% (range of prevalence 0.6-6.9%). While participants with previous pulmonary tuberculosis had a lower pre-bronchodilator FEV₁ (mean - 0.7 SDs, 95% CI - 0.92 to - 0.57), FVC (- 0.52 SDs, 95% CI - 0.69 to - 0.33) and FEV₁/FVC (- 0.59 SDs, 95% CI - 0.76 to - 0.43) as compared to those who did not, we did not find an association between HAP exposure and previous pulmonary tuberculosis (adjusted odds ratio = 0.86; 95% CI 0.56-1.32).

CONCLUSIONS

There was no association between HAP exposure and self-reported previous pulmonary tuberculosis in five population-based studies conducted worldwide.

Effect of household air pollution due to solid fuel combustion on childhood respiratory diseases in a semi urban population in Sri Lanka

BACKGROUND

Household air pollution from combustion of solid fuels for cooking and space heating is one of the most important risk factors of the global burden of disease. This study was aimed to determine the association between household air pollution due to combustion of biomass fuel in Sri Lankan households and self-reported respiratory symptoms in children under 5 years.

METHODS

A prospective study was conducted in the Ragama Medical Officer of Health area in Sri Lanka. Children under 5 years were followed up for 12 months. Data on respiratory symptoms were extracted from a symptom diary. Socioeconomic data and the main fuel type used for cooking were recorded. Air quality measurements were taken during the preparation of the lunch meal over a 2-h period in a subsample of households.

RESULTS

Two hundred and sixty two children were followed up. The incidence of infection induced asthma (RR = 1.77, 95%CI;1.098-2.949) was significantly higher among children resident in households using biomass fuel and kerosene (considered as the high exposure group) as compared to children resident in households using Liquefied Petroleum Gas (LPG) or electricity for cooking (considered as the low exposure group), after adjusting for confounders. Maternal education was significantly associated with the incidence of infection induced asthma after controlling for other factors including exposure status. The incidence of asthma among male children was significantly higher than in female children (RR = 1.17; 95% CI 1.01-1.37). Having an industry causing air pollution near the home and cooking inside the living area were significant risk factors of rhinitis (RR = 1.39 and 2.67, respectively) while spending less time on cooking was a protective factor (RR = 0.81). Houses which used biomass fuel had significantly higher concentrations of carbon monoxide (CO) (mean 2.77 ppm vs 1.44 ppm) and particulate matter_2.5 (PM_2.5) (mean 1.09 mg/m³ vs 0.30 mg/m³) as compared to houses using LPG or electricity for cooking.

CONCLUSION

The CO and PM_2.5 concentrations were significantly higher in households using biomass fuel for cooking. There was a 1.6 times higher risk of infection induced asthma (IIA) among children of the high exposure group as compared to children of the low exposure group, after controlling for other factors. Maternal education was significantly associated with the incidence of IIA after controlling for exposure status and other variables.

Study protocol for a stepped-wedge randomized cookstove intervention in rural Honduras: household air pollution and cardiometabolic health

BACKGROUND

Growing evidence links household air pollution exposure from biomass-burning cookstoves to cardiometabolic disease risk. Few randomized controlled interventions of cookstoves (biomass or otherwise) have quantitatively characterized changes in exposure and indicators of cardiometabolic health, a growing and understudied burden in low- and middle-income countries (LMICs). Ideally, the solution is to transition households to clean cooking, such as with electric or liquefied petroleum gas stoves; however, those unable to afford or to access these options will continue to burn biomass for the foreseeable future. Wood-burning cookstove designs such as the Justa (incorporating an engineered combustion zone and chimney) have the potential to substantially reduce air pollution exposures. Previous cookstove intervention studies have been limited by stove types that did not substantially reduce exposures and/or by low cookstove adoption and sustained use, and few studies have incorporated community-engaged approaches to enhance the intervention.

METHODS/DESIGN

We conducted an individual-level, stepped-wedge randomized controlled trial with the Justa cookstove intervention in rural Honduras. We enrolled 230 female primary cooks who were not pregnant, non-smoking, aged 24-59 years old, and used traditional wood-burning cookstoves at baseline. A community advisory board guided survey development and communication with participants, including recruitment and retention strategies. Over a 3-year study period, participants completed 6 study visits approximately 6 months apart. Half of the women received the Justa after visit 2 and half after visit 4. At each visit, we measured 24-h gravimetric personal and kitchen fine particulate matter (PM2.5) concentrations, qualitative and quantitative cookstove use and adoption metrics, and indicators of cardiometabolic health. The primary health endpoints were blood pressure, C-reactive protein, and glycated hemoglobin. Overall study goals are to explore barriers and enablers of new cookstove adoption and sustained use, compare health endpoints by assigned cookstove type, and explore the exposure-response associations between PM2.5 and indicators of cardiometabolic health.

DISCUSSION

This trial, utilizing an economically feasible, community-vetted cookstove and evaluating endpoints relevant for the major causes of morbidity and mortality in LMICs, will provide critical information for household air pollution stakeholders globally.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT02658383 , posted January 18, 2016, field work completed May 2018. Official title, "Community-Based Participatory Research: A Tool to Advance Cookstove Interventions." Principal Investigator Maggie L. Clark, Ph.D. Last update posted July 12, 2018.

Impact of biomass fuel exposure from traditional stoves on lung functions in adult women of a rural Indian village

Introduction

Exposure to biomass fuel (BMF) from traditional cookstoves inflicts an enormous burden of morbidities in women across the developing world. This study aims to assess the lung function and its association with the indoor air pollutants generated using BMF.

Materials and Methods

This cross-sectional study including 310 women was conducted in a rural village of India. Households were divided into two groups based on the cooking fuel, the BMF group and the liquefied petroleum gas (LPG) group. Information on respiratory symptoms and socioeconomic status was obtained using a standard questionnaire. Indoor air concentration for PM₁₀and PM_2.5was measured during cooking hours. Pulmonary function tests (PFTs) were conducted for the women inhabitants.

Results

On comparing the two groups, the concentration of PM₁₀(890.26 ± 59.59 vs. 148.66 ± 31.97) μg/m³ and PM_2.5(728.90 ± 50.20 vs. 99.76 ± 41.80) μg/m³ (P < 0.01) were higher in the group using BMF. The respiratory symptoms such as wheezing, dyspnea, chronic cough, and nocturnal cough, were significantly more common in the group using BMF. A significant difference was seen in the lung function indices between the two groups. A significant negative correlation of respiratory indices with duration of exposure and the particulate matter (PM) values suggested a greater decline on lung function among women exposed to increased concentrations of PM. On comparing participants with normal and abnormal PFT, it was seen that the use of BMF (odds ratio [OR] 8.01; 95% confidence interval [CI] 4.80, 13.36, P < 0.001) and the duration of exposure to BMF (OR 1.16; 95% CI 1.13, 1.20., P < 0.001) increased the odds of having an abnormal PFT.

Conclusions

This study shows a high prevalence of respiratory symptoms and an abnormal pulmonary function in women exposed to BMF.

[Current status of household polluting fuel use in adults aged 40 years and older in China, 2014]

Objective: To analyze the status and distribution characteristics of household polluting fuel use in China. Methods: The data were collected from the adults aged ≥40 years who were recruited through multi-stage stratified cluster sampling in 2014-2015 COPD surveillance conducted in 31 provinces (autonomous regions and municipalities) in China. A total of 75 107 adults aged ≥40 years in 125 surveillance points were surveyed in face to face interview. Polluting fuels included biomass fuels (wood, dung, crop residues and charcoal), coal (including coal dust and lignite) and kerosene. The weighted percentage of family using polluting fuels, combustion method for cooking or heating and ventilation installation with 95%CI were estimated by complex sampling design. Results: According to the survey results from 75 075 adults, the percentage of family using polluting fuels for cooking or heating was 59.9% (95%CI: 54.2%-65.7%), the percentage in rural areas was significantly higher than that in urban areas (P<0.001). As for different polluting fuels, the percentage of using only biomass fuels for cooking or heating was 25.9% (95%CI:20.5%-31.3%), the percentage of using only coal (including kerosene) was 18.9% (95%CI: 13.2%-24.7%), and the percentage of using both biomass fuels and coal was 15.1% (95%CI: 10.8%-19.4%). Among seven geographic areas in China, the percentages of using biomass fuels ranged from 53.8% in southern China to 23.0% in northern China (P=0.039), the percentages of using coal (including kerosene) ranged from 59.5% in northwestern China to 22.3% in southern China (P=0.001). Among the families using polluting fuels, the percentages of mainly using traditional open fires and stoves were 21.3% (95%CI: 16.9%-25.8%) and 31.5% (95%CI: 25.8%-37.2%), respectively; the percentage of having ventilation installation was72.7% (95%CI: 66.9%-78.5%). Conclusions: Household polluting fuel use is common in China, but differs with area, traditional fuel combustion method is widely used, the coverage of ventilation installation need to be improved. In order to promote COPD prevention and control, it is necessary to develop strategies on fuels and fuel combustion method improvement to reduce indoor air pollution resulted from household fuel combustion.

Household biomass fuel use, blood pressure and carotid intima media thickness; a cross sectional study of rural dwelling women in Southern Nigeria

BACKGROUND

Rising prevalence of cardiovascular disease requires in-depth understanding of predisposing factors. Studies show an association between air pollution and CVD but this association is not well documented in southern Nigeria where the use of biomass fuels (BMF) for domestic purposes is prevalent.

PURPOSE

This study aimed to explore the association between household BMF use and blood pressure (BP) and carotid intima media thickness (CIMT) among rural-dwelling women.

METHODS

A cross-sectional study of 389 women aged 18 years and older. Questionnaires were used to obtain data on predominant fuel used and a brief medical history. Wood, charcoal and agricultural waste were classified as BMF while kerosene, bottled gas and electricity were classified as non-BMF. Blood pressure and CIMT were measured using standard protocols. Regression analysis was used to assess the relationship between fuel type and BP, CIMT, pre-hypertension and hypertension after adjusting for confounders.

RESULTS

There was a significant difference in the mean (standard deviation) systolic BP (135.3, 26.7 mmHg vs 123.8, 22.6 mmHg; p < 0.01), diastolic BP (83.7, 18.5 mmHg vs 80.1, 13.8 mmHg; p = 0.043) and CIMT (0.63, 0.16 mm vs 0.56, 0.14 mm; p = 0.004) among BMF users compared to non-BMF users. In regression analysis, the use of BMF was significantly associated with 2.7 mmHg higher systolic BP (p = 0.040), 0.04 mm higher CIMT (p = 0.048) in addition to increased odds of pre-hypertension (OR 1.67 95% CI 1.56, 4.99, P = 0.035) but not hypertension (OR 1.23 95% CI 0.73, 2.07, P = 0.440).

CONCLUSION

In this population, there was a significant association between BMF use and increased SBP, CIMT and pre-hypertension. This requires further exploration with a large-scale longitudinal study design because there are policy implications for countries like Nigeria where a large proportion of the population still rely on BMF for domestic energy.

Effect on blood pressure and eye health symptoms in a climate-financed randomized cookstove intervention study in rural India

BACKGROUND

Air pollution from cooking with solid fuels is a potentially modifiable risk factor for increased blood pressure and may lead to eye irritation.

OBJECTIVES

To evaluate whether a climate motivated cookstove intervention reduced blood pressure and eye irritation symptoms in Indian women.

METHODS

Households using traditional stoves were randomized to receive a rocket stove or continue using traditional stoves. Systolic (SBP) and diastolic blood pressure (DBP), and self-reported eye symptoms were measured twice, pre-intervention and at least 124 days post-intervention in women > 25 years old in control (N = 111) and intervention (N = 111) groups in rural Karnataka, India. Daily (24-h) fine particle (PM_2.5) mass and absorbance (Abs) were measured in cooking areas at each visit. Mixed-effect models were used to estimate before-and-after differences in SBP, DBP and eye symptoms.

RESULTS

We observed a lower SBP (-2.0 (-4.5, 0.5) mmHg) and DBP (-1.1 (-2.9, 0.6) mmHg) among exclusive users of intervention stove, although confidence intervals included zero. Stacking or mixed use of intervention and traditional stoves contributed to a small increase in SBP 2.6 (-0.4, 5.7) mmHg) and DBP (1.2 (-0.9, 3.3) mmHg). Exclusive and mixed stove users experienced higher post-intervention reductions, on average, in self-reported eye irritation symptoms for burning sensation in eyes, and eyes look red often compared to control. Median air pollutant concentrations increased post-intervention in all stove groups, with the lowest median PM_2.5 increase in the exclusive intervention stove group.

CONCLUSIONS

Health benefits were limited due to stacking and lower-than-predicted efficiency of the intervention stove in the field. Stove adoption and use behavior, in addition to stove technology, affects achievement of health co-benefits. Carbon-financing schemes need to align with international guidelines that have been set based on health outcomes to maximize health co-benefits from cookstove interventions.

Characteristics and potential health risk of rural Tibetans' exposure to polycyclic aromatic hydrocarbons during summer period

Biomass fuels remain main energy sources in many remote rural regions, but potential health hazards from exposure to biomass combustion fumes have not been adequately assessed. Combustion of biomass fuels generates abundant polycyclic aromatic hydrocarbons (PAHs); hence residential exposure to PAHs can be used to evaluate the potential health risk to remote rural populations. The present study selected rural Tibetans to address the above-mentioned issue. Samples of indoor air and dust, human urine and local foods (Tsampa flour and buttered tea) were collected from five rural households in Langkazi County, an agricultural and pasturing region in Tibet of China in the summer season, which represented the best-case scenario as no heating was required. Residential exposure to PAHs by adults amounted to benzo[a]pyrene equivalent (BaP_eq) dosages of 110-760, 1.2-50 and 0.5-23 ng d^-1 for ingestion, inhalation and dermal contact, respectively. Daily intakes of naphthalene, fluorene, phenanthrene and pyrene estimated from urinary monohydroxy PAH metabolites and from diet and inhalation exposure to PAHs were comparable (3.9, 1.9, 12 and 3.3 μg d^-1 versus 9.5, 2.5, 5.1 and 1.1 μg d^-1), indicating the utility of external exposure in assessing daily intake of PAHs. The median incremental lifetime cancer risk was 32 × 10^-6 (95% confidence interval: 0.7-73 × 10^-6) for ingestion and 2.4 × 10^-6 (95% confidence interval: 0.02-12 × 10^-6) for inhalation and dermal contact combined, indicating moderate to slight potential cancer risk. Diet is the dominant source of health hazards for rural Tibetans, but cooking fumes also present a meaningful concern. The present study demonstrates that the pristine lifestyles of remote rural residents may be of global health concern, and merit further investigations.

Effects of a liquefied petroleum gas stove intervention on pollutant exposure and adult cardiopulmonary outcomes (CHAP): study protocol for a randomized controlled trial

BACKGROUND

Biomass fuel smoke is a leading risk factor for the burden of disease worldwide. International campaigns are promoting the widespread adoption of liquefied petroleum gas (LPG) in resource-limited settings. However, it is unclear if the introduction and use of LPG stoves, in settings where biomass fuels are used daily, reduces pollution concentration exposure, improves health outcomes, or how cultural and social barriers influence the exclusive adoption of LPG stoves.

METHODS

We will conduct a randomized controlled, field intervention trial of LPG stoves and fuel distribution in rural Puno, Peru, in which we will enroll 180 female participants aged 25-64 years and follow them for 2 years. After enrollment, we will collect information on sociodemographic characteristics, household characteristics, and cooking practices. During the first year of the study, LPG stoves and fuel tanks will be delivered to the homes of 90 intervention participants. During the second year, participants in the intervention arm will keep their LPG stoves, but the gas supply will stop. Control participants will receive LPG stoves and vouchers to obtain free fuel from distributors at the beginning of the second year, but gas will not be delivered. Starting at baseline, we will collect longitudinal measurements of respiratory symptoms, pulmonary function, blood pressure, endothelial function, carotid artery intima-media thickness, 24-h dietary recalls, exhaled carbon monoxide, quality-of-life indicators, and stove-use behaviors. Environmental exposure assessments will occur six times over the 2-year follow-up period, consisting of 48-h personal exposure and kitchen concentration measurements of fine particulate matter and carbon monoxide, and 48-h kitchen concentrations of nitrogen dioxide for a subset of 100 participants.

DISCUSSION

Findings from this study will allow us to better understand behavioral patterns, environmental exposures, and cardiovascular and pulmonary outcomes resulting from the adoption of LPG stoves. If this trial indicates that LPG stoves are a feasible and effective way to reduce household air pollution and improve health, it will provide important information to support widespread adoption of LPG fuel as a strategy to reduce the global burden of disease.

TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT02994680 , Cardiopulmonary Outcomes and Household Air Pollution (CHAP) Trial. Registered on 28 November 2016.

Exposure to ambient particulate matter alters the microbial composition and induces immune changes in rat lung

Background

Ambient particulate matter exposure has been shown to increase the risks of respiratory diseases. However, the role of the lung microbiome and the immune response to inhaled particulate matter are largely unexplored. We studied the influence of biomass fuel and motor vehicle exhaust particles on the lung microbiome and pulmonary immunologic homeostasis in rats.

Methods

Fifty-seven Sprague–Dawley rats were randomly divided into clean air (CON), biomass fuel (BMF), and motor vehicle exhaust (MVE) groups. After a 4-week exposure, the microbial composition of the lung was assessed by 16S rRNA pyrosequencing, the structure of the lung tissue was assessed with histological analysis, the phagocytic response of alveolar macrophages to bacteria was determined by flow cytometry, and immunoglobulin concentrations were measured with commercial ELISA kits.

Results

There was no significant difference in lung morphology between the groups. However, the BMF and MVE groups displayed greater bacterial abundance and diversity. Proteobacteria were present in higher proportions in the MVE group, and 12 bacterial families differed in their relative abundances between the three groups. In addition, particulate matter exposure significantly increased the capacity of alveolar macrophages to phagocytose bacteria and induced changes in immunoglobulin levels.

Conclusion

We demonstrated that particulate matter exposure can alter the microbial composition and change the pulmonary immunologic homeostasis in the rat lung.

[Preliminary analysis of lung function of population with biofuel smoke exposure]

Objective: To analyse the impaired lung functions of people with biofuel smoke exposure. Methods: Nonsmokers with biofuel smoke exposure were selected as research objects in a mountainous area of northern Guangdong where the families used biofuels as main energies and the nonsmokers without biofuel smoke exposure in the same area as control. Questionnaire interviews and spirometry tests were performed on all subjects. To analyse the differences of lung functions in both. Results: Seventy hundred and seventeen subjects were enro1led in this study.There were 530 nonsmokers with biofuel smoke exposure(observation group) including 442 women and 88 men, average age 54±10. There were 187 nonsmokers without biofuel smoke exposure(control group) including 141 women and 46 men, average age 54±10. There was no significant difference between two groups in age, height, weight, BMI, waist circumference, hip circumference and waist/hip ratio(P>0.05). The pulmonary ventilation function index(FEV(1)%Pred, FEV(1)/FVC) in the observation group was significantly less than that in control group [(100±18) vs.(106±25); (80±10) vs.(83±6) respectively, P<0.05]. Small airway function index(PEF25, PEF50, PEF75, MMPEF and MMPEF%Pred) was significantly less than that in control group(P<0.01). According to the univariate regression analysis and multivariate regression analysis, regression coefficients between BIOFUEL-INDEX and FEV/FVC was -0.1, 95%CI(-0.1, -0.1, P<0.01). According to the threshold analysis, the vertice of BIOFUEL-INDEX was 46.0, where the predicted Y value was 81.76, 95%CI (80.2, 83.33). When BIOFUEL-INDEX<46.0, the regression coefficient was 0, 95%CI (-0.1, 0.0)(P>0.05); when BIOFUEL-INDEX> 46.0, the regression coefficient 2 was -0.1, 95%CI (-0.2, -0.1)(P<0.01). The difference between coefficient 2 and 1 was -0.1, 95%CI (-0.2, 0.0), which was statistically significant (P<0.05). The Log-Likelihood ratio between Model I and Model Ⅱ had statistical significance (P=0.019). Conclusions: The biofuel smokes exposure causes damages in lung function.

Household biomass fuel use, asthma symptoms severity, and asthma underdiagnosis in rural schoolchildren in Nigeria: a cross-sectional observational study

Background

In 2014, the International Study of Asthma and Allergies in Childhood (ISAAC) reported that the highest prevalence of symptoms of severe asthma was found in the low- and middle-income countries (LMICs), including Nigeria. While exposure to biomass fuel use may be an important risk factor in the development of asthma, its association with asthma symptoms severity has not been well-established. The aim of this study is to extend the spectrum of environmental risk factors that may be contributing towards increasing asthma morbidity, especially asthma symptoms severity in rural schoolchildren in Nigeria and to examine possible asthma underdiagnosis among this population.

Methods

Authors conducted a cross-sectional survey in three rural communities in Nigeria. Asthma symptoms were defined according to the ISAAC criteria. Information on the types of household fuel used for cooking was used to determine household cooking fuel status. Asthma symptoms severity was defined based on frequencies of wheeze, day- and night-time symptoms, and speech limitations. Logistic regression analyses were used to explore associations.

Results

A total of 1,690 Nigerian schoolchildren participated in the study. Overall, 37 (2.2%) had diagnosed asthma and 413 (24.4%) had possible asthma (asthma-related symptoms but not diagnosed asthma). Children from biomass fuel households had higher proportion of possible asthma (27.7 vs. 22.2%; p < 0.05) and symptoms of severe asthma (18.2 vs. 7.6%; p = 0.048). In adjusted analyses, biomass fuel use was associated with increased odds of severe symptoms of asthma [odds ratios (OR) = 2.37; 95% CI: 1.16–4.84], but not with possible asthma (OR = 1.22; 95% CI: 0.95–1.56).

Conclusion

In rural Nigerian children with asthma symptoms, the use of biomass fuel for cooking is associated with an increased risk of severe asthma symptoms. There is additional evidence that rural children might be underdiagnosed for asthma.

What Do We Know about Anthracofibrosis? A Literature Review

Recently, the significance of anthracosis in the tracheobronchial tree, lung parenchyma, and even non-respiratory organs has been postulated and discussed in association with other diseases, especially tuberculosis. We reviewed the current literature by using the following key words in Medline/PubMed, Embase, and Google Scholar databases: anthracosis, anthracofibrosis, anthracotic bronchitis, biomass fuels, and mixed-dust pneumoconiosis. The bibliographies of eligible papers were also reviewed for further relevant articles. A total of 37 studies were assessed. The content of these studies was then divided into specific categories. Considering the pathogenesis, along with histopathological, radiological, and bronchoscopic results regarding anthracotic lesions, we suggest these findings be defined as "ANTHRACOSIS SYNDROME". For the first time, we describe a syndrome involving black pigmentation, which was previously thought to involve only the tracheobronchial tree. Until recently, it was not considered to be a single syndrome with different sites of involvement.

Fine grain separation for the production of biomass fuel from mixed municipal solid waste

The main goal of the project MARSS (Material Advanced Sustainable Systems) is to build a demonstration plant in order to recover a renewable biomass fuel suitable for the use in biomass power plants out of mixed municipal solid waste (MMSW). The demonstration plant was constructed in Mertesdorf (Germany), working alongside an existing mechanical-biological treatment plant, where the MMSW is biological dried under aerobe conditions in rotting boxes. The focus of the presented sorting campaign was set on the processing of fine grain particles minor than 11.5mm which have the highest mass content and biogenic energy potential of the utilized grain size fractions. The objective was to produce a biomass fuel with a high calorific value and a low content of fossil (plastic, synthetic) materials while maximizing the mass recovery. Therefore, the biogenic components of the dried MMSW are separated from inert and fossil components through various classification and sifting processes. In three experimental process setups of different processing depths, the grain size fraction 4-11.5mm was sifted by the use of air sifters and air tables.

The intensive margin of technology adoption--Experimental evidence on improved cooking stoves in rural Senegal

Today, almost 3 billion people in developing countries rely on biomass as primary cooking fuel, with profound negative implications for their well-being. Improved biomass cooking stoves are alleged to counteract these adverse effects. This paper evaluates take-up and impacts of low-cost improved stoves through a randomized controlled trial. The randomized stove is primarily designed to curb firewood consumption, but not smoke emissions. Nonetheless, we find considerable effects not only on firewood consumption, but also on smoke exposure and, consequently, smoke-related disease symptoms. The reduced smoke exposure results from behavioural changes in terms of increased outside cooking and a reduction in cooking time. We conclude that in order to assess the effectiveness of a technology-oriented intervention, it is critical to not only account for the incidence of technology adoption - the extensive margin - but also for the way the new technology is used - the intensive margin.

Biomass fuels and coke plants are important sources of human exposure to polycyclic aromatic hydrocarbons, benzene and toluene

Large amounts of carcinogenic polycyclic aromatic hydrocarbons (PAHs), benzene and toluene (BT) might be emitted from incomplete combustion reactions in both coal tar factories and biomass fuels in rural China. The health effects arising from exposure to PAHs and BT are a concern for residents of rural areas close to coal tar plants. To assess the environmental risk and major exposure sources, 100 coke plant workers and 25 farmers in Qujing, China were recruited. The levels of 10 mono-hydroxylated PAHs (OH-PAHs), four BT metabolites and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in the urine collected from the subjects were measured. The 8-OHdG levels in the urine were determined to evaluate the oxidative DNA damage induced by the PAHs and BT. The results showed that the levels of the OH-PAHs, particularly those of 1-hydroxynathalene and 1-hydroxypyrene, in the farmers were 1-7 times higher than those in the workers. The concentrations of the BT metabolites were comparable between the workers and farmers. Although the exact work location within a coke oven plant might affect the levels of the OH-PAHs, one-way ANOVA revealed no significant differences for either the OH-PAHs levels or the BT concentrations among the three groups working at different work sites. The geometric mean concentration (9.17 µg/g creatinine) of 8-OHdG was significantly higher in the farmers than in the plant workers (6.27 µg/g creatinine). The levels of 8-OHdG did not correlate with the total concentrations of OH-PAHs and the total levels of BT metabolites. Incompletely combusted biomass fuels might be the major exposure source, contributing more PAHs and BT to the local residents of Qujing. The estimated daily intakes (EDIs) of naphthalene and fluorene for all of the workers and most of the farmers were below the reference doses (RfDs) recommended by the U.S. Environmental Protection Agency (EPA), except for the pyrene levels in two farmers. However, the EDIs of benzene in the workers and local farmers ranged from 590 to 7239 µg/day, and these levels were 2- to 30-fold higher than the RfDs recommended by the EPA. Biomass fuel combustion and industrial activities related to coal tar were the major sources of the PAH and BT exposure in the local residents. Using biomass fuels for household cooking and heating explains the higher exposure levels observed in the farmers relative to the workers at the nearby coal tar-related industrial facility.

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.

Solid fuel use is a major risk factor for acute coronary syndromes among rural women: a matched case control study

OBJECTIVES

Almost half of the world's population uses solid fuel for cooking, exposing women to high levels of particulate pollution in indoor air. The risk of acute coronary syndrome (ACS) was assessed among rural women, according to their use of solid fuel.

STUDY DESIGN

Matched case control study.

METHODS

Data were collected at a public tertiary care hospital in a rural district of Pakistan. Seventy-three women with ACS were compared with controls, individually matched for sex and age (± 5 years), who were admitted to hospital for other reasons. Fuels used for cooking and exposures to potentially confounding variables were ascertained through a questionnaire administered at interview and measurement of height and weight. Conditional logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (95% CIs).

RESULTS

After adjustment for potential confounding factors, current use of solid fuel was strongly associated with ACS (OR 4.8, 95% CI: 1.5-14.8), and risk was lowest in women who had last used solid fuel more than 15 years earlier. The population attributable fraction for ACS in relation to current use of solid fuel was 49.0% (95% CI: 41.3%-57.4%).

CONCLUSIONS

These findings support the hypothesis that indoor air pollution from use of solid fuel is an important cause of ACS. Our study demonstrates the feasibility of case-control studies in rural populations of women to address this question, and is an encouragement to larger and statistically more powerful investigations.

Chronic obstructive pulmonary disease: Does gender really matter?

Background:

Limited data is available on the clinical expression of chronic obstructive pulmonary disease (COPD) from India. The impact of gender on expression of COPD has received even less attention. Apart from tobacco smoke, indoor air pollution, especially from biomass fuel may play an important role in development of COPD in women.

Materials and Methods:

Seven hundred and two patients of COPD were studied regarding the etiological and risk factors leading to COPD, gender-related differences in clinical presentation, radiological expression of COPD and the co-morbidities in COPD.

Results:

Tobacco smoke in the form of beedi smoking was the predominant smoke exposure in males, whereas smoke from biofuel burning was the predominant exposure in females. As compared to males, females were younger, reported more dyspnea, more severe bronchial obstruction, more exacerbations, and exhibited higher prevalence of systemic features. Also, females smoked less and had lesser incidence of productive cough, lower body mass index, lesser co-morbidities and less number of hospital admissions as compared to males. Males were more likely than females to have an emphysema-predominant phenotype, while airway-predominant disease was more common among females.

Conclusion:

The current study shows that gender-related differences do exist in COPD patients. Understanding these differences in etiological agent and clinical picture will help early diagnosis of COPD in females.