Selected HAP studies - January - March 2013
Dan Campbell
Cleaner cooking solutions to achieve health, climate, and economic co-benefits.
Abstract
Nearly half the world's population must rely on solid fuels such as biomass (wood, charcoal, agricultural residues, and animal dung) and coal for household energy, burning them in inefficient open fires and stoves with inadequate ventilation. Household solid fuel combustion is associated with four million premature deaths annually; contributes to forest degradation, loss of habitat and biodiversity, and climate change; and hinders social and economic progress as women and children spend hours every day collecting fuel. Several recent studies, as well as key emerging national and international efforts, are making progress towards enabling wide-scale household adoption of cleaner and more efficient stoves and fuels. While significant challenges remain, these efforts offer considerable promise to save lives, improve forest sustainability, slow climate change, and empower women around the world.
Characterization of ultrafine particulate matter from traditional and improved biomass cookstoves.
Source
Department of Mechanical Engineering, The University of British Columbia , 6250 Applied Science Lane, Vancouver, British Columbia V6T 1Z4, Canada.
Abstract
Biomass combustion in cookstoves has a substantial impact on human health, affects CO2 levels in the atmosphere, and black carbon (BC) and organic carbon (OC) affect the earth's radiative balance. Various initiatives propose to replace traditional fires with "improved" (nontraditional)cookstoves to offset negative local and global effects. In this laboratory study, we compared the size, composition, and morphology of ultrafine particulate emissions from a "three-stone" traditional fire to those from two improved stove designs (one "rocket", one "gasifier"). Measurement tools included a scanning mobility particle sizer, PTFE and quartz filter samples, and transmission electron microscopy. In the improved stoves, particulate mass (PM) emissions factors were much lower although median particle size was also lower: 35 and 24 nm for the rocket and gasifier, respectively, vs 61 nm for the three-stone fire. Particles from improved stoves formed clearly defined chain agglomerates and independent spheres with little evidence of volatile matter and had a higher proportion of BC to total PM, although overall BC emissions factors were fairly uniform. The 3-fold increase in quantities of sub-30 nm particles from improved cookstoves warrants further consideration by health scientists, with due consideration to the higher combustion efficiencies of improved cookstoves.
Coarse particulate matter and airborne endotoxin within wood stove homes.
Source
Department of Biomedical and Pharmaceutical Sciences, University of Montana, Center for Environmental Health Sciences, 32 Campus Drive, Missoula, Montana, 59812, United States.
Abstract
Emissions from indoor biomass burning are a major public health concern in developing areas of the world. Less is known about indoor air quality, particularly airborne endotoxin, in homes burning biomass fuel in residential wood stoves in higher income countries. A filter-based sampler was used to evaluate wintertime indoor coarse particulate matter (PM10-2.5 ) and airborne endotoxin (EU/m3 , EU/mg) concentrations in 50 homes using wood stoves as their primary source of heat in western Montana. We investigated number of residents, number of pets, dampness (humidity), and frequency of wood stove usage as potential predictors of indoor airborne endotoxin concentrations. Two 48-hour sampling events per home revealed a mean winter PM10-2.5 concentration (± sd) of 12.9 (± 8.6) μg/m3 , while PM2.5 concentrations averaged 32.3 (± 32.6) μg/m3 . Endotoxin concentrations measured from PM10-2.5 filter samples were 9.2 (± 12.4) EU/m3 and 1,010 (± 1,524) EU/mg. PM10-2.5 and PM2.5 were significantly correlated in wood stove homes (r=0.36, p<0.05). The presence of pets in the homes was associated with PM10-2.5 but not with endotoxin concentrations. Importantly, none of the other measured home characteristics was a strong predictor of airborne endotoxin, including frequency of residential wood stove usage. © 2013 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.
Acute Lower Respiratory Infection in Childhood and Household Fuel Use in Bhaktapur, Nepal.
Source
Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, California, USA.
Abstract
BACKGROUND:
Globally, solid fuels are used by about 3 billion people for cooking and heating. These fuels have been associated with many health effects, including acute lower respiratory infection (ALRI) in young children. Nepal has a high prevalence of use of biomass for cooking and heating.
OBJECTIVE:
This case-control study was conducted among a population in the Bhaktapur municipality, Nepal, with the objectives of investigating the relationships of cookfuel type to ALRI in young children.
METHODS:
Cases with ALRI and age-matched controls were enrolled from an open cohort of children 2-35 months old, under active monthly surveillance for ALRI. A questionnaire was used to obtain information on family characteristics, including household cooking and heating appliances and fuels. The main analysis was carried out using conditional logistic regression. Population-attributable fractions (PAF) for stove types were calculated.
RESULTS:
917 children (452 cases and 465 controls) were recruited into the study. Relative to use of electricity for cooking, ALRI was increased in association with any use of biomass stoves (OR = 1.93; 95% CI: 1.24, 2.98), kerosene stoves (OR = 1.87; 95% CI: 1.24, 2.83), gas stoves(OR = 1.62; 95% CI: 1.05, 2.50). Use of wood, kerosene or coal heating was also associated with ALRI (OR = 1.45, 95% CI: 0.97, 2.14), compared with no heating or electricity or gas heating. PAFs for ALRI were 18.0% (95% CI: 8.1, 26.9%) and 18.7% (95% CI: 8.4%-27.8%), for biomass and kerosene stoves, respectively.
CONCLUSIONS:
The study supports previous reports indicating that use of biomass as a household fuel is a risk factor for ALRI, and provides new evidence that use of kerosene for cooking may also be a risk factor for ALRI in young children.
Household levels of nitrogen dioxide and pediatric asthma severity.
Source
Center for Perinatal, Pediatric and Environmental Epidemiology, Yale University School of Public Health, New Haven, CT 06510, USA.
Abstract
BACKGROUND:
Adverse respiratory effects in children with asthma are associated with exposures to nitrogen dioxide (NO2). Levels indoors can be much higher than outdoors. Primary indoor sources of NO2 are gas stoves, which are used for cooking by one-third of U.S. households. We investigated the effects of indoor NO2 exposure on asthma severity among an ethnically and economically diverse sample of children, controlling for season and indoor allergen exposure.
METHODS:
Children 5-10 years of age with active asthma (n = 1,342) were recruited through schools in urban and suburban Connecticut and Massachusetts (2006-2009) for a prospective, year-long study with seasonal measurements of NO2 and asthma severity. Exposure to NO2 was measured passively for four, month-long, periods with Palmes tubes. Asthma morbidity was concurrently measured by a severity score and frequency of wheeze, night symptoms, and use of rescue medication. We used adjusted, hierarchical ordered logistic regression models to examine associations between household NO2 exposure and health outcomes.
RESULTS:
Every 5-fold increase in NO2 exposure above a threshold of 6 ppb was associated with a dose-dependent increase in risk of higher asthma severity score (odds ratio = 1.37 [95% confidence interval = 1.01-1.89]), wheeze (1.49 [1.09-2.03]), night symptoms (1.52 [1.16-2.00]), and rescue medication use (1.78 [1.33-2.38]).
CONCLUSIONS:
Asthmatic children exposed to NO2 indoors, at levels well below the U.S. Environmental Protection Agency outdoor standard (53 ppb), are at risk for increased asthma morbidity. Risks are not confined to inner city children, but occur at NO2 concentrations common in urban and suburban homes.
Biomass stoves and lens opacity and cataract in Nepalese women.
Source
School of Public Health, University of California, Berkeley, Berkeley, California, USA.
Abstract
PURPOSE:
Cataract is the most prevalent cause of blindness in Nepal. Several epidemiologic studies have associated cataracts with use of biomass cookstoves. These studies, however, have had limitations, including potential control selection bias and limited adjustment for possible confounding. This study, in Pokhara City, in an area of Nepal where biomass cookstoves are widely used without direct venting of the smoke to the outdoors, focuses on preclinical measures of opacity while avoiding selection bias and taking into account comprehensive data on potential confounding factors.
METHODS:
Using a cross-sectional study design, severity of lenticular damage, judged on the LOCS (Lens Opacities Classification System) III scales, was investigated in women (n = 143), aged 20 to 65 years, without previously diagnosed cataract. Linear and logistic regression analyses were used to examine the relationships with stove type and length of use. Clinically significant cataract, used in the logistic regression models, was defined as a LOCS III score ≥2.
RESULTS:
Using gas cookstoves as the reference group, logistic regression analysis for nuclear cataract showed evidence of relationships with stove type: for biomass stoves, the odds ratio was 2.58 (95% confidence interval, 1.22 to 5.46); and for kerosene stoves, the odds ratio was 5.18 (95% confidence interval, 0.88 to 30.38). Similar results were found for nuclear color (LOCS III score ≥2), but no association was found with cortical cataracts. Supporting a relationship between biomass stoves and nuclear cataract was a trend with years of exposure to biomasscookstoves (p = 0.01). Linear regression analyses did not show clear evidence of an association between lenticular damage and stove types. Biomass fuel used for heating was not associated with any form of opacity.
CONCLUSIONS:
This study provides support for associations of biomass and kerosene cookstoves with nuclear opacity and change in nuclear color. The novel associations with kerosene cookstove use deserve further investigation.
Evaluation of clinical and functional parameters in female subjects with biomass smoke exposure.
Source
Department of Pulmonary Diseases and Cardiovascular Surgery, Research State Hospital, Istanbul, Turkey.
Abstract
BACKGROUND:
Indoor air pollution and exposure to biomass smoke is a risk factor for pulmonary diseases among women in developing countries. We aimed to assess clinical and functional findings and exposure duration and to evaluate their relationships in patients who used biomass products as fuel and who presented to the clinic due to respiratory symptoms.
METHODS:
Fifty-five patients who had been referred to the hospital between January 2008 and December 2010 and who met the inclusion criteria were accepted to the study. Data on the place they live, biomass exposure duration, lung function parameters, and arterial blood gases were recorded.
RESULTS:
Statistically significant differences in FEV₁%, FEV₁ (L) and, FEV₁/FVC existed between the subgroups of duration of biomass exposure (P = .001). FEV₁% and FEV₁/FVC were highest in the < 30 hour-years exposure group. In the presence of animal dung use, the odds ratio and 95% CI for the risk of FEV(1)/FVC < 70% was 3.5 (0.88-10.29). Subjects who used animal dung and wood for cooking and heating had severe and very severe FEV₁ stages.
CONCLUSIONS:
Biomass exposure can have effects on lung function test parameters. Animal dung use is primarily related to risk of deterioration of FEV₁/FVC, when compared to other biomass fuels. Protective health measures should be taken by assessing the risks in areas where biomass exposure is intense, improving poor design of the stoves and ventilation, and switching to better clean energy sources such as natural gas and solar energy.
Life cycle assessment to evaluate the environmental impact of biochar implementation in conservation agriculture in Zambia.
Source
Norwegian Geotechnical Institute NGI, Oslo, Norway. magnus.s...@ngi.no
Abstract
Biochar amendment to soil is a potential technology for carbon storage and climate change mitigation. It may, in addition, be a valuable soil fertility enhancer for agricultural purposes in sandy and/or weathered soils. A life cycle assessment including ecological, health and resource impacts has been conducted for field sites in Zambia to evaluate the overall impacts of biochar for agricultural use. The life cycle impacts from conservation farming using cultivation growth basins and precision fertilization with and without biochar addition were in the present study compared to conventional agricultural methods. Three different biochar production methods were evaluated: traditional earth-mound kilns, improved retort kilns, and micro top-lit updraft (TLUD) gasifier stoves. The results confirm that the use of biochar in conservation farming is beneficial for climate change mitigation purposes. However, when including health impacts from particle emissions originating from biochar production, conservation farming plus biochar from earth-mound kilns generally results in a larger negative effect over the whole life cycle than conservation farming without biochar addition. The use of cleaner technologies such as retort kilns or TLUDs can overcome this problem, mainly because fewer particles and less volatile organic compounds, methane and carbon monoxide are emitted. These results emphasize the need for a holistic view on biochar use in agricultural systems. Of special importance is the biochar production technique which has to be evaluated from both environmental/climate, health and social perspectives.
Proinflammatory effects of cookstove emissions on human bronchial epithelial cells.
Source
Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA.
Abstract
Approximately half of the world's population uses biomass fuel for indoor cooking and heating. This form of combustion typically occurs in open fires or primitive stoves.
Human exposure to emissions from indoor biomass combustion is a global health concern, causing an estimated 1.5 million premature deaths each year. Many 'improved' stoves have been developed to address this concern; however,
studies that examine exposure-response with cleaner-burning, more efficient stoves are few. The objective of this research was to evaluate the effects of traditional and cleaner-burning stove emissions on an established model
of the bronchial epithelium. We exposed well-differentiated, normal human bronchial epithelial cells to emissions from a single biomass combustion event using either a traditional three-stone fire or one of two energy-efficientstoves.
Air-liquid interface cultures were exposed using a novel, aerosol-to-cell deposition system. Cellular expression of a panel of three pro-inflammatory markers was evaluated at 1 and 24 h following exposure. Cells exposed to emissions from the cleaner-burning stoves generated
significantly fewer amounts of pro-inflammatory markers than cells exposed to emissions from a traditional three-stone fire. Particulate matter emissions from each cookstove were substantially different, with the three-stone fire producing the largest concentrations
of particles (by both number and mass). This study supports emerging evidence that more efficient cookstoves have the potential to reduce respiratory inflammation in settings where solid fuel combustion is used to meet basic
domestic needs. PRACTICAL IMPLICATIONS: Emissions from more efficient, cleaner-burning cookstoves produced less inflammation in well-differentiated bronchial lung cells. The results support evidence that more efficientcookstoves can
reduce the health burden associated with exposure to indoor pollution from the combustion of biomass.
Are rocket mud stoves associated with lower indoor carbon monoxide and personal exposure in rural Kenya?
Source
Department of Social and Environmental Health Research, Faculty of Public Health and Policy, London School of Hygiene & Tropical Medicine, London, UK. caroline...@lshtm.ac.uk
Abstract
Household use of biomass fuels is a major source of indoor air pollution and poor health in developing countries. We conducted a cross-sectional investigation in rural Kenya to assess household
air pollution in homes with traditional three-stone stove and rocket mud stove (RMS), a low-cost unvented wood stove. We conducted continuous measurements of kitchen carbon monoxide (CO) concentrations and personal exposures in 102 households. Median 48-h
kitchen and personal CO concentrations were 7.3 and 6.5 ppm, respectively, for three-stone stoves, while the corresponding concentrations for RMS were 5.8 and 4.4 ppm. After adjusting for kitchen location, ventilation, socio-economic
status, and fuel moisture content, the use of RMS was associated with 33% lower levels of kitchen CO [95% Confidence Interval (CI), 64.4-25.1%] and 42% lower levels of personal CO (95% CI, 66.0-1.1%) as compared to three-stone stoves.
Differences in CO concentrations by stove type were more pronounced when averaged over the cooking periods, although they were attenuated after adjusting for confounding. In conclusion, RMS appear to lower kitchen and personal CO concentrations compared to
the traditional three-stone stoves but overall, the CO concentrations remain high. PRACTICAL IMPLICATIONS: The rocket mud stoves (RMS) were associated with lower CO concentrations compared to three-stone stoves.
However, the difference in concentrations was modest and concentrations in both stove groups exceeded the WHO guideline of 7 μg/m(3) , suggesting the unvented RMSs on their own are unlikely to appreciably benefit health in this population. Greater air quality
benefit could be realized if the stoves were complemented with behavior change, including education on extinguishing fire when not in use as well as fuel drying, and cooking in locations that are separate from the main house.
Chimney stoves modestly improved Indoor Air Quality measurements compared with traditional open firestoves: results from a small-scale intervention study in rural Peru.
Source
Instituto de Investigación Nutricional, Lima, Peru; Swiss Tropical and Public Health Institute, Basel, Switzerland; Department of Epidemiology and Public Health, University of Basel, Basel, Switzerland.
Abstract
Nearly half of the world's population depends on biomass fuels to meet domestic energy needs, producing high levels of pollutants responsible for substantial morbidity and mortality. We compare carbon monoxide (CO) and particulate matter (PM(2.5) ) exposures and kitchen concentrations in households with study-promoted intervention (OPTIMA-improved stoves and control stoves) in San Marcos Province, Cajamarca Region, Peru. We determined 48-h indoor air concentration levels of CO and PM(2.5) in 93 kitchen environments and personal exposure, after OPTIMA-improved stoves had been installed for an average of 7 months. PM(2.5) and CO measurements did not differ significantly between OPTIMA-improved stoves and control stoves. Although not statistically significant, a post hoc stratification of OPTIMA-improved stoves by level of performance revealed mean PM(2.5) and CO levels of fully functional OPTIMA-improved stoves were 28% lower (n = 20, PM(2.5,) 136 μg/m(3) 95% CI 54-217) and 45% lower (n = 25, CO, 3.2 ppm, 95% CI 1.5-4.9) in the kitchen environment compared with the control stoves (n = 34, PM(2.5) , 189 μg/m(3) , 95% CI 116-261; n = 44, CO, 5.8 ppm, 95% CI 3.3-8.2). Likewise, although not statistically significant, personal exposures for OPTIMA-improved stoves were 43% and 17% lower for PM(2.5) (n = 23) and CO (n = 25), respectively. Stove maintenance and functionality level are factors worthy of consideration for future evaluations of stove interventions.
Evaluation of interventions to reduce air pollution from biomass smoke on mortality in Launceston, Australia: retrospective analysis of daily mortality, 1994-2007.
Source
Menzies Research Institute Tasmania and Rural Clinical School, University of Tasmania, Tasmania, Australia. fay.jo...@utas.edu.au
Abstract
OBJECTIVE:
To assess the effect of reductions in air pollution from biomass smoke on daily mortality.
DESIGN:
Age stratified time series analysis of daily mortality with Poisson regression models adjusted for the effects of temperature, humidity, day of week, respiratory epidemics, and secular mortality trends, applied to an intervention and control community.
SETTING:
Central Launceston, Australia, a town in which coordinated strategies were implemented to reduce pollution from wood smoke and central Hobart, a comparable city in which there were no specific air quality interventions.
PARTICIPANTS:
67,000 residents of central Launceston and 148,000 residents of central Hobart (at 2001 census).
INTERVENTIONS:
Community education campaigns, enforcement of environmental regulations, and a wood heater replacement programme to reduce ambient pollution from residential wood stoves started in the winter of 2001.
MAIN OUTCOME MEASURES:
Changes in daily all cause, cardiovascular, and respiratory mortality during the 6.5 year periods before and after June 2001 in Launceston and Hobart.
RESULTS:
Mean daily wintertime concentration of PM(10) (particulate matter with particle size <10 µm diameter) fell from 44 µg/m(3) during 1994-2000 to 27 µg/m(3) during 2001-07 in Launceston. The period of improved air quality was associated with small non-significant reductions in annual mortality. In males the observed reductions in annual mortality were larger and significant for all cause (-11.4%, 95% confidence interval -19.2% to -2.9%; P=0.01), cardiovascular (-17.9%, -30.6% to -2.8%; P=0.02), and respiratory (-22.8%, -40.6% to 0.3%; P=0.05) mortality. In wintertime reductions in cardiovascular (-19.6%, -36.3% to 1.5%; P=0.06) and respiratory (-27.9%, -49.5% to 3.1%; P=0.07) mortality were of borderline significance (males and females combined). There were no significant changes in mortality in the control city of Hobart.
CONCLUSIONS:
Decreased air pollution from ambient biomass smoke was associated with reduced annual mortality in males and with reduced cardiovascular and respiratory mortality during winter months.
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Destroy user interface controlImpact of locally-produced, ceramic cookstoves on respiratory disease in children in rural western Kenya.
Source
Emory University School of Medicine, Atlanta, Georgia, USA. efo...@gmail.com
Abstract
Household air pollution is a risk factor for pneumonia, the leading cause of death among children < 5 years of age. From 2008 to 2010, a Kenyan organization sold ≈ 2,500 ceramic cookstoves (upesi jiko) that produce less visible household smoke than 3-stone firepits. During a year-long observational study, we made 25 biweekly visits to 200 homes to determine stove use and observe signs of acute respiratory infection in children < 3 years of age. Reported stove use included 3-stone firepit only (81.8%), upesi jiko only (15.7%), and both (2.3%). Lower, but not statistically significant, percentages of children in upesi jiko-using households than 3-stone firepit-using households had observed cough (1.3% versus 2.9%, rate ratio [RR] 0.48, 95% confidence interval [CI]: 0.22-1.03), pneumonia (0.9% versus 1.7%, RR 0.60, 95% CI: 0.24-1.48), and severe pneumonia (0.3% versus 0.6%, RR 0.66, 95% CI: 0.17-2.62). Upesi jiko use did not result in significantly lower pneumonia rates. Further research on the health impact of improved cookstoves is warranted.
Longitudinal relationship between personal CO and personal PM2.5 among women cooking with woodfiredcookstoves in Guatemala.
Source
Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA.
Abstract
Household air pollution (HAP) due to solid fuel use is a major public health threat in low-income countries. Most health effects are thought to be related to exposure to the fine particulate matter (PM) component of HAP, but it is currently impractical to measure personal exposure to PM in large studies. Carbon monoxide (CO) has been shown in cross-sectional analyses to be a reliable surrogate for particles<2.5 µm in diameter (PM2.5) in kitchens where wood-burning cookfires are a dominant source, but it is unknown whether a similar PM2.5-CO relationship exists for personal exposures longitudinally. We repeatedly measured (216 measures, 116 women) 24-hour personal PM2.5 (median [IQR] = 0.11 [0.05, 0.21] mg/m(3)) and CO (median [IQR] = 1.18 [0.50, 2.37] mg/m(3)) among women cooking over open woodfires or chimney woodstoves in Guatemala. Pollution measures were natural-log transformed for analyses. In linear mixed effects models with random subject intercepts, we found that personal CO explained 78% of between-subject variance in personal PM2.5. We did not see a difference in slope by stove type. This work provides evidence that in settings where there is a dominant source of biomass combustion, repeated measures of personal CO can be used as a reliable surrogate for an individual's PM2.5 exposure. This finding has important implications for the feasibility of reliably estimating long-term (months to years) PM2.5 exposure in large-scale epidemiological and intervention studies of HAP.
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Destroy user interface controlSystematic review and meta-analysis of the associations between indoor air pollution and tuberculosis.
Source
London School of Hygiene and Tropical Medicine, London, UK. colin....@Ishtm.ac.uk
Abstract
OBJECTIVE:
Half the world's population uses biomass fuel for their daily needs but the resultant emissions and indoor air pollution (IAP) are harmful to health. So far, evidence for a link between IAP and tuberculosis (TB) was insufficient. We report an updated systematic review due to recent increase in the evidence and growing interest in testing interventions.
METHODS:
Systematic search of PubMed (including Medline), CAB abstracts (through Ovid SP) and Web of Knowledge using the following search terms: 'IAP or biomass or cooking smoke' and 'TB'. 452 abstracts were reviewed, and only 12 articles were deemed to be reporting the effects of IAP on TB and were taken forward to full review, and one study was added through hand search of references. Data on measures of effect of IAP on TB were extracted, and meta-analysis was carried out to estimate pooled measures of effect.
RESULTS:
Thirteen studies have reported investigating association between IAP and TB since 1996. TB cases are more likely to be exposed to IAP than healthy controls (pooled OR 1.30; 95% CI, 1.04-1.62; P = 0.02).
CONCLUSIONS:
There is increasingly strong evidence for an association between IAP and TB. Further studies are needed to understand the burden of TB attributable to IAP. Interventions such as clean cook stoves to reduce the adverse effects of IAP merit rigorous evaluation, particularly in Africa and India where the prevalence of IAP and TB is high.