Over half the world is exposed daily to the smoke from combustion of solid fuels. Chronic obstructive pulmonary disease (COPD) is one of the main contributors to the global burden of disease and can ...be caused by biomass smoke exposure. However, studies of biomass exposure and COPD show a wide range of effect sizes. The aim of this systematic review was to quantify the impact of biomass smoke on the development of COPD and define reasons for differences in the reported effect sizes.
A systematic review was conducted of studies with sufficient statistical power to calculate the health risk of COPD from the use of solid fuel, which followed standardised criteria for the diagnosis of COPD and which dealt with confounding factors. The results were pooled by fuel type and country to produce summary estimates using a random effects model. Publication bias was also estimated.
There were positive associations between the use of solid fuels and COPD (OR=2.80, 95% CI 1.85 to 4.0) and chronic bronchitis (OR=2.32, 95% CI 1.92 to 2.80). Pooled estimates for different types of fuel show that exposure to wood smoke while performing domestic work presents a greater risk of development of COPD and chronic bronchitis than other fuels.
Despite heterogeneity across the selected studies, exposure to solid fuel smoke is consistently associated with COPD and chronic bronchitis. Efforts should be made to reduce exposure to solid fuel by using either cleaner fuel or relatively cleaner technology while performing domestic work.
Household Air Pollution (HAP) from biomass cooking fuels is a major cause of morbidity and mortality in low-income settings worldwide. In Nepal the use of open stoves with solid biomass fuels is the ...primary method of domestic cooking. To assess patterns of domestic air pollution we performed continuous measurement of carbon monoxide (CO) and particulate Matter (PM2.5) in 12 biomass fuel households in Janakpur, Nepal. We measured kitchen PM2.5 and CO concentrations at one-minute intervals for an approximately 48-h period using the TSI DustTrak II 8530/SidePak AM510 (TSI Inc, St. Paul MN, USA) or EL-USB-CO data logger (Lascar Electronics, Erie PA, USA) respectively. We also obtained information regarding fuel, stove and kitchen characteristics and cooking activity patterns. Household cooking was performed in two daily sessions (median total duration 4 h) with diurnal variability in pollutant concentrations reflecting morning and evening cooking sessions and peak concentrations associated with fire-lighting. We observed a strong linear relationship between PM2.5 measurements obtained by co-located photometric and gravimetric monitoring devices, providing local calibration factors of 4.9 (DustTrak) and 2.7 (SidePak). Overall 48-h average CO and PM2.5 concentrations were 5.4 (SD 4.3) ppm (12 households) and 417.6 (SD 686.4) μg/m3 (8 households), respectively, with higher average concentrations associated with cooking and heating activities. Overall average PM2.5 concentrations and peak 1-h CO concentrations exceeded WHO Indoor Air Quality Guidelines. Average hourly PM2.5 and CO concentrations were moderately correlated (r = 0.52), suggesting that CO has limited utility as a proxy measure for PM2.5 exposure assessment in this setting. Domestic indoor air quality levels associated with biomass fuel combustion in this region exceed WHO Indoor Air Quality standards and are in the hazardous range for human health.
•Intensive PM2.5 and CO monitoring was performed in 12 biomass fuel-using households in Janakpur.•Domestic cooking activity patterns and kitchen, stove and fuel characteristics were recorded.•Temporal PM2.5 and CO patterns demonstrated diurnal variability reflecting morning and evening cooking sessions.•Average PM2.5 and peak CO concentrations both exceeded World Health Organization (WHO) Indoor Air Quality Guidelines.•Concentrations of PM2.5 and CO were moderately correlated during cooking periods.
The exposure of children to air pollution in low resource settings is believed to be high because of the common use of biomass fuels for cooking. We used microenvironment sampling to estimate the ...respirable fraction of air pollution (particles with median diameter less than 4μm) to which 7–9year old children in southern Nepal were exposed. Sampling was conducted for a total 2649h in 55 households, 8 schools and 8 outdoor locations of rural Dhanusha. We conducted gravimetric and photometric sampling in a subsample of the children in our study in the locations in which they usually resided (bedroom/living room, kitchen, veranda, in school and outdoors), repeated three times over one year. Using time activity information, a 24-hour time weighted average was modeled for all the children in the study. Approximately two-thirds of homes used biomass fuels, with the remainder mostly using gas. The exposure of children to air pollution was very high. The 24-hour time weighted average over the whole year was 168μg/m3. The non-kitchen related samples tended to show approximately double the concentration in winter than spring/autumn, and four times that of the monsoon season. There was no difference between the exposure of boys and girls. Air pollution in rural households was much higher than the World Health Organization and the National Ambient Air Quality Standards for Nepal recommendations for particulate exposure.
•Air pollution exposure (respirable PM) was estimated for children in Nepal.•Gravimetric and photometric microenvironment sampling was conducted.•Total sampling was repeated three times over a year and totaled over 2500 hours.•The 24-hour time weighted average was 168µg/m3.•There was substantial variability from season to season and by fuel type.•There was no difference in exposure between boys and girls.
Abstract
More than half the world's population still rely on burning biomass fuels to heat and light their homes and cook food. Household air pollution, a common component of which is inhalable ...particulate matter (PM), emitted from biomass burning is associated with increased vulnerability to respiratory infection and an enhanced risk of developing chronic obstructive pulmonary disease. In the light of an emerging hypothesis linking chronic PM exposure during childhood and increased vulnerability to respiratory diseases in adulthood, in a chain of events involving oxidative stress, reduced immunity and subsequent infection, the aim of this study was to characterise the oxidative potential (OP) of PM collected during the burning of wood and mixed biomass, whilst cooking food in the Kathmandu Valley, Nepal. Our assessments were based on the capacity of the particles to deplete the physiologically relevant antioxidants from a validated, synthetic respiratory tract lining fluid (RTLF). Incubation of mixed biomass and wood smoke particles suspensions with the synthetic RTLF for 4 h resulted in a mean loss of ascorbate of 64.76 ± 16.83% and 83.37 ± 14.12% at 50 μg/ml, respectively. Reduced glutathione was depleted by 49.29 ± 15.22% in mixed biomass and 65.33 ± 13.01% in wood smoke particles under the same conditions. Co-incubation with the transition metal chelator diethylenetriaminepentaacetate did not inhibit the rate of ascorbate oxidation, indicating a negligible contribution by redox-active metals in these samples. The capacity of biomass smoke particles to elicit oxidative stress certainly has the potential to contribute towards negative health impacts associated with traditional domestic fuels in the developing world.
The association between occupational exposure and COPD reported previously has mostly been derived from studies relying on self-reported exposure to vapors, gases, dust, or fumes (VGDF), which could ...be subjective and prone to biases. The aim of this study was to assess the strength of association between exposure and COPD from studies that derived exposure by job exposure matrices (JEMs).
A systematic search of JEM-based occupational COPD studies published between 1980 and 2015 was conducted in PubMed and EMBASE, followed by meta-analysis. Meta-analysis was performed using a random-effects model, with results presented as a pooled effect estimate with 95% confidence intervals (CIs). The quality of study (risk of bias and confounding) was assessed by 13 RTI questionnaires. Heterogeneity between studies and its possible sources were assessed by Egger test and meta-regression, respectively.
In all, 61 studies were identified and 29 were included in the meta-analysis. Based on JEM-based studies, there was 22% (pooled odds ratio =1.22; 95% CI 1.18-1.27) increased risk of COPD among those exposed to airborne pollutants arising from occupation. Comparatively, higher risk estimates were obtained for general populations JEMs (based on expert consensus) than workplace-based JEM were derived using measured exposure data (1.26; 1.20-1.33 vs 1.14; 1.10-1.19). Higher risk estimates were also obtained for self-reported exposure to VGDF than JEMs-based exposure to VGDF (1.91; 1.72-2.13 vs 1.10; 1.06-1.24). Dusts, particularly biological dusts (1.33; 1.17-1.51), had the highest risk estimates for COPD. Although the majority of occupational COPD studies focus on dusty environments, no difference in risk estimates was found for the common forms of occupational airborne pollutants.
Our findings highlight the need to interpret previous studies with caution as self-reported exposure to VGDF may have overestimated the risk of occupational COPD.
Summary
Background
Skin protective creams (PCs) are used widely in industrial work environments to prevent irritant contact dermatitis. However, workplace studies remain equivocal in terms of their ...effectiveness, which may be partly owing to whether the PC remains on the skin.
Objectives
To assess the practicability of using skin occlusion testing in a workplace as a method to determine whether PCs applied under controlled conditions can reduce skin damage against known irritants. This study also compares two methods of skin evaluation: clinical dermatological assessment and bioengineering techniques.
Methods
Daily occlusion testing for 1 h (over two consecutive weeks) was conducted in an engineering company on the volar forearm of 21 healthy volunteer engineers with sodium lauryl sulfate (SLS) and a PC that was used on site. The engineers conducted their normal work activities during the occlusion testing period. The skin areas tested were assessed using transepidermal water loss (TEWL), Chroma Meter and by visual dermatological scoring.
Results
Testing with PC and SLS together showed that PC does not prevent irritant contact dermatitis but significantly reduced skin damage compared with SLS alone (P < 0·01). The changes in skin were evident earlier with the biophysical measurements when compared with the dermatological assessment.
Conclusions
Occlusion testing is a useful method for assessing the potential effectiveness of protective creams and can be used in a workplace without affecting work practices. TEWL and the Chroma Meter provide useful objective information and should be used in combination with dermatological examinations.
What's already known about this topic?
Barrier (protective) creams are used widely in industrial workplace settings to prevent irritant contact dermatitis but evidence for their effectiveness is inconclusive.
What does this study add?
This study demonstrates that the potential effectiveness of protective creams can be evaluated using occlusion testing in the workplace.
This study also evaluates the use of bioengineering techniques alongside dermatological assessment when assessing skin changes.
Display omitted
•Numerical modelling indicates that heat loss through outer wall is predominant.•Model FD 2.2 exhibits better combustion characteristics in contrast to traditional ...cookstoves.•Controlled airflow rates during initial & last phases facilitates clean combustion.•CO emission could be reduced in the range of 95.91–98.58%•Emission of PM2.5 could be lowered by 96.50–99.31%
This article presents an experimental and computational study of a forced draft cookstove having separate primary and secondary air fans, while utilizing pellets as fuel. A two-dimensional axisymmetric computational fluid dynamics model of the developed cookstove has been created in ANSYS Fluent to analyze the fluid flow, temperature distribution and heat loss from the different parts of the cookstove. The simulation results showed that more than one fourth of the total heat produced by the burning of fuel was being lost to the ambient environment through the outermost wall of cookstove. Also, the temperature of the outer wall of the cookstove was found to be higher than the temperature of secondary air being preheated in the annulus chamber. Therefore, the developed model was further modified by using glass wool insulation which resulted in an increment of 5.7% in thermal efficiency, while the emissions of CO and PM2.5 were reduced by 7.1% and 25.9%, respectively. The performance of the developed models have also been compared with other pellet based forced draft models available globally, and the thermal efficiency of the Mimi Moto cookstove was found to be highest followed by FD 2.2 model.
China has high COPD rates, even among never-regular smokers. Little is known about nonrespiratory disease risks, especially vascular morbidity and mortality after developing airflow obstruction (AFO) ...in Chinese adults.
We aimed to investigate the prospective association of prevalent AFO with major vascular morbidity and mortality.
In 2004-2008, a nationwide prospective cohort study recruited 512,891 men and women aged 30-79 years from 10 diverse localities across China, tracking cause-specific mortality and coded episodes of hospitalization for 9 years. Cox regression yielded adjusted HRs for vascular diseases comparing individuals with spirometry-defined prevalent AFO at baseline to those without.
Of 489,382 participants with no vascular disease at baseline, 6.8% had AFO, with prevalence rising steeply with age. Individuals with prevalent AFO had significantly increased vascular mortality (n=1,429, adjusted HR 1.29, 95% CI 1.21-1.36). There were also increased risks of hemorrhagic stroke (n=823, HR 1.18, 95% CI 1.09-1.27), major coronary events (n=635, HR 1.33, 95% CI 1.22-1.45), and heart failure (n=543, HR 2.19, 95% CI 1.98-2.41). For each outcome, the risk increased progressively with increasing COPD severity and persisted among never-regular smokers.
Among adult Chinese, AFO was associated with significantly increased risks of major vascular morbidity and mortality. COPD management should be integrated with vascular disease prevention and treatment programs to improve long-term prognosis.
Population-based studies of the occupational contribution to chronic obstructive pulmonary disease generally rely on self-reported exposures to vapours, gases, dusts and fumes (VGDF), which are ...susceptible to misclassification.
To develop an airborne chemical job exposure matrix (ACE JEM) for use with the UK Standard Occupational Classification (SOC 2000) system.
We developed the ACE JEM in stages: (i) agreement of definitions, (ii) a binary assignation of exposed/not exposed to VGDF, fibres or mists (VGDFFiM), for each of the individual 353 SOC codes and (iii) assignation of levels of exposure (L; low, medium and high) and (iv) the proportion of workers (P) likely to be exposed in each code. We then expanded the estimated exposures to include biological dusts, mineral dusts, metals, diesel fumes and asthmagens.
We assigned 186 (53%) of all SOC codes as exposed to at least one category of VGDFFiM, with 23% assigned as having medium or high exposure. We assigned over 68% of all codes as not being exposed to fibres, gases or mists. The most common exposure was to dusts (22% of codes with >50% exposed); 12% of codes were assigned exposure to fibres. We assigned higher percentages of the codes as exposed to diesel fumes (14%) compared with metals (8%).
We developed an expert-derived JEM, using a strict set of a priori defined rules. The ACE JEM could also be applied to studies to assess risks of diseases where the main route of occupational exposure is via inhalation.
PDF
