Background 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. Methods 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. Results 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. Conclusion 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.

Adverse health effects from exposure to air pollution are a global challenge and of widespread concern. Recent high ambient concentration episodes of air pollutants in European cities highlighted the dynamic nature of human exposure and the gaps in data and knowledge about exposure patterns. In order to support health impact assessment it is essential to develop a better understanding of individual exposure pathways in people's everyday lives by taking account of all environments in which people spend time. Here we describe the development, validation and results of an exposure method applied in a study conducted in Scotland. A low-cost particle counter based on light-scattering technology - the Dylos 1700 was used. Its performance was validated in comparison with equivalent instruments (TEOM-FDMS) at two national monitoring network sites (R(2)=0.9 at a rural background site, R(2)=0.7 at an urban background site). This validation also provided two functions to convert measured PNCs into calculated particle mass concentrations for direct comparison of concentrations with equivalent monitoring instruments and air quality limit values. This study also used contextual and time-based activity data to define six microenvironments (MEs) to assess everyday exposure of individuals to short-term PM2.5 concentrations. The Dylos was combined with a GPS receiver to track movement and exposure of individuals across the MEs. Seventeen volunteers collected 35 profiles. Profiles may have a different overall duration and structure with respect to times spent in different MEs and activities undertaken. Results indicate that due to the substantial variability across and between MEs, it is essential to measure near-complete exposure pathways to allow for a comprehensive assessment of the exposure risk a person encounters on a daily basis. Taking into account the information gained through personal exposure measurements, this work demonstrates the added value of data generated by the application of low-cost monitors.

Objective: To investigate the associations between Parkinson’s disease and other degenerative parkinsonian syndromes and environmental factors in five European countries. Methods: A case–control study of 959 prevalent cases of parkinsonism (767 with Parkinson’s disease) and 1989 controls in Scotland, Italy, Sweden, Romania and Malta was carried out. Cases were defined using the United Kingdom Parkinson’s Disease Society Brain Bank criteria, and those with drug-induced or vascular parkinsonism or dementia were excluded. Subjects completed an interviewer-administered questionnaire about lifetime occupational and hobby exposure to solvents, pesticides, iron, copper and manganese. Lifetime and average annual exposures were estimated blind to disease status using a job-exposure matrix modified by subjective exposure modelling. Results were analysed using multiple logistic regression, adjusting for age, sex, country, tobacco use, ever knocked unconscious and family history of Parkinson’s disease. Results: Adjusted logistic regression analyses showed significantly increased odds ratios for Parkinson’s disease/parkinsonism with an exposure–response relationship for pesticides (low vs no exposure, odds ratio (OR) = 1.13, 95% CI 0.82 to 1.57, high vs no exposure, OR = 1.41, 95% CI 1.06 to 1.88) and ever knocked unconscious (once vs never, OR = 1.35, 95% CI 1.09 to 1.68, more than once vs never, OR = 2.53, 95% CI 1.78 to 3.59). Hypnotic, anxiolytic or antidepressant drug use for more than 1 year and a family history of Parkinson’s disease showed significantly increased odds ratios. Tobacco use was protective (OR = 0.50, 95% CI 0.42 to 0.60). Analyses confined to subjects with Parkinson’s disease gave similar results. Conclusions: The association of pesticide exposure with Parkinson’s disease suggests a causative role. Repeated traumatic loss of consciousness is associated with increased risk.

Cookstove intervention programs have been increasing over the past two (2) decades in Low and Middle Income Countries (LMICs) across the globe. However, there remains uncertainty regarding the effects of these interventions on household air pollution concentrations, personal exposure concentrations and health outcomes. The primary objective was to determine if household air pollution (HAP) interventions were associated with improved indoor air quality (IAQ) in households in LMICs. Given the potential impact of HAP interventions on health, a secondary objective was to evaluate the effectiveness of HAP interventions to improve health in populations receiving these interventions. OVID Medline, Ovid Embase, SCOPUS and PubMED were searched from their inception until December 2015 with no restrictions on study design. The WHO Global database of household air pollution measurements and Members' archives were also reviewed together with the reference lists of identified reviews and relevant articles. We considered randomized controlled trials, or non-randomized control trials, or before-and-after studies; original studies; studies conducted in a LMIC (based on the United Nations Human Development Report released in March 2013 (World Bank, 2013); interventions that were explicitly aimed at improving IAQ and/or health from solid fuel use; studies published in a peer-reviewed journal or student theses or reports; studies that reported on outcomes which was indicative of IAQ or/and health. There was no restriction on the type of comparator (e.g. household receiving plancha vs. household using traditional cookstove) used in the intervention study. Five review authors independently used pre-designed data collection forms to extract information from the original studies and assessed risk of bias using the Effective Public Health Practice Project (EPHPP). We computed standardized weighted mean difference (SMD) using random-effects models. Heterogeneity was computed using the Q and I2-statistics. We examined the influence of various characteristics on the study-specific effect estimates by stratifying the analysis by population type, study design, intervention type, and duration of exposure monitoring. The trim and fill method was used to assess the potential impact of missing studies. Fifty-five studies met our a priori inclusion criteria and were included in the systematic review. Fifteen studies provided 43 effect estimates for our meta-analysis. The largest improvement in HAP was observed for average particulate matter (PM) (SMD=1.57) concentrations in household kitchens (1.03), followed by daily personal average concentrations of PM (1.18), and carbon monoxide (CO) concentrations in kitchens. With respect to personal PM, significant improvement was observed in studies of children (1.26) and studies monitoring PM for ≥24h (1.32). This observation was also noted in terms of studies of kitchen concentrations of CO. A significant improvement was also observed for kitchen levels of PM in both adult populations (1.56) and in RCT/cohort designs (1.59) involving replacing cookstoves without chimneys. Our findings on health outcomes were inconclusive. We observed high statistical between study variability in the study-specific estimate. Thus, care should be taken in concluding that HAP interventions - as currently designed and implemented - support reductions in the average kitchen and personal levels of PM and CO. Further, there is limited evidence that current stand-alone HAP interventions yield any health benefits. Post-intervention levels of pollutants were generally still greatly in excess of the relevant WHO guideline and thus a need to promote cleaner fuels in LMICs to reduce HAP levels below the WHO guidelines. The review has been registered with PROSPERO (registration number CRD42014009768).

Volatile organic compounds (VOCs) are ubiquitous domestic pollutants. Their role in asthma/allergy development and exacerbations is uncertain. This systematic review investigated whether domestic VOC exposure increases the risk of developing and/or exacerbating asthma and allergic disorders.We systematically searched 11 databases and three trial repositories, and contacted an international panel of experts to identify published and unpublished experimental and epidemiological studies.8455 potentially relevant studies were identified; 852 papers were removed after de-duplication, leaving 7603 unique papers that were screened. Of these, 278 were reviewed in detail and 53 satisfied the inclusion criteria. Critical appraisal of the included studies indicated an overall lack of high-quality evidence and substantial risk of bias in this body of knowledge. Aromatics (i.e. benzenes, toluenes and xylenes) and formaldehyde were the main VOC classes studied, both in relation to the development and exacerbations of asthma and allergy. Approximately equal numbers of studies reported that exposure increased risks and that exposure was not associated with any detrimental effects.The available evidence implicating domestic VOC exposure in the risk of developing and/or exacerbating asthma and allergy is of poor quality and inconsistent. Prospective, preferably experimental studies, investigating the impact of reducing/eliminating exposure to VOC, are now needed in order to generate a more definitive evidence base to inform policy and clinical deliberations in relation to the management of the now substantial sections of the population who are either at risk of developing asthma/allergy or living with established disease.