Pro-inflammatory potential of particles from residential wood smoke and traffic : importance of physicochemical characteristics

Exposure to particulate matter (PM) has been associated with increased cardiopulmonary morbidity and mortality, and inflammation has been suggested as a mechanistic link between PM exposure and adverse health effects. Physicochemical properties such as size surface area and chemistry are thought to influence the negative effects of particles. In this study, the physicochemical properties of particles from residential wood smoke and traffic were analysed by transmission electron microscopy techniques and bulk chemical analyses. In addition, the pro-inflammatory potential of particles from these two sources was compared in in vitro model systems, and the influence of physicochemical particle properties on the pro-inflammatory response was investigated. In the in vitro experiments, particles from traffic induced a higher release of pro-inflammatory mediators, while wood smoke particles induced a greater reduction in proliferation. Thus, particles from these two sources may induce different biological effects, but be equally harmful. The organic fraction was the particle fraction that was found to exert the strongest influence on the biological responses. Reduction of the organic fraction of PM emissions could, therefore, be a useful approach for environmental strategies to reduce emissions of hazardous PM components

Physicochemical characterisation of combustion particles from vehicle exhaust and residential wood smoke

BACKGROUND: Exposure to ambient particulate matter has been associated with a number of adverse health effects. Particle characteristics such as size, surface area and chemistry seem to influence the negative effects of particles. In this study, combustion particles from vehicle exhaust and wood smoke, currently used in biological experiments, were analysed with respect to microstructure and chemistry. METHODS: Vehicle exhaust particles were collected in a road tunnel during two seasons, with and without use of studded tires, whereas wood smoke was collected from a stove with single-stage combustion. Additionally, a reference diesel sample (SRM 2975) was analysed. The samples were characterised using transmission electron microscopy techniques (TEM/HRTEM, EELS and SAED). Furthermore, the elemental and organic carbon fractions were quantified using thermal optical transmission analysis and the content of selected PAHs was determined by gas chromatography-mass spectrometry. RESULTS: Carbon aggregates, consisting of tens to thousands of spherical primary particles, were the only combustion particles identified in all samples using TEM. The tunnel samples also contained mineral particles originating from road abrasion. The geometric diameters of primary carbon particles from vehicle exhaust were found to be significantly smaller (24 ± 6 nm) than for wood smoke (31 ± 7 nm). Furthermore, HRTEM showed that primary particles from both sources exhibited a turbostratic microstructure, consisting of concentric carbon layers surrounding several nuclei in vehicle exhaust or a single nucleus in wood smoke. However, no differences were detected in the graphitic character of primary particles from the two sources using SAED and EELS. The total PAH content was higher for combustion particles from wood smoke as compared to vehicle exhaust, whereas no source difference was found for the ratio of organic to total carbon. CONCLUSION: Combustion particles from vehicle exhaust and residential wood smoke differ in primary particle diameter, microstructure, and PAH content. Furthermore, the analysed samples seem suitable for assessing the influence of physicochemical characteristics of particles on biological responses

Health effects of residential wood smoke particles: the importance of combustion conditions and physicochemical particle properties

Background: Residential wood combustion is now recognized as a major particle source in many developed countries, and the number of studies investigating the negative health effects associated with wood smoke exposure is currently increasing. The combustion appliances in use today provide highly variable combustion conditions resulting in large variations in the physicochemical characteristics of the emitted particles. These differences in physicochemical properties are likely to influence the biological effects induced by the wood smoke particles. Outline: The focus of this review is to discuss the present knowledge on physicochemical properties of wood smoke particles from different combustion conditions in relation to wood smoke-induced health effects. In addition, the human wood smoke exposure in developed countries is explored in order to identify the particle characteristics that are relevant for experimental studies of wood smoke-induced health effects. Finally, recent experimental studies regarding wood smoke exposure are discussed with respect to the applied combustion conditions and particle properties. Conclusion: Overall, the reviewed literature regarding the physicochemical properties of wood smoke particles provides a relatively clear picture of how these properties vary with the combustion conditions, whereas particle emissions from specific classes of combustion appliances are less well characterised. The major gaps in knowledge concern; (i) characterisation of the atmospheric transformations of wood smoke particles, (ii) characterisation of the physicochemical properties of wood smoke particles in ambient and indoor environments, and (iii) identification of the physicochemical properties that influence the biological effects of wood smoke particles

Pulmonary phthalate exposure and asthma - is PPAR a plausible mechanistic link?

Due to their extensive use as plasticisers in numerous consumer products, phthalates have become ubiquitous environmental contaminants. An increasing number of epidemiological studies suggest that exposure to phthalates may be associated with worsening or development of airway diseases. Peroxisome Proliferation Activated Receptors (PPAR)s, identified as important targets for phthalates in early studies in rodent liver, have been suggested as a possible mechanistic link. In this review we discuss the likelihood of an involvement of PPARs in asthma development and exacerbation due to pulmonary phthalate exposure. First, we go through the literature on indoor air levels of phthalates and pulmonary phthalate kinetics. These data are then used to estimate the pulmonary phthalate levels due to inhalation exposure. Secondly, the literature on phthalate-induced activation or modulation of PPARs is summarized. Based on these data, we discuss whether pulmonary phthalate exposure is likely to cause PPAR activation, and if this is a plausible mechanism for adverse effects of phthalates in the lung. It is concluded that the pulmonary concentrations of some phthalates may be sufficient to cause a direct activation of PPARs. Since PPARs mainly mediate anti-inflammatory effects in the lungs, a direct activation is not a likely molecular mechanism for adverse effects of phthalates. However, possible modulatory effects of phthalates on PPARs deserve further investigation, including partial antagonist effects and/or cross talk with other signalling pathways. Moreover other mechanisms, including interactions between phthalates and other receptors, could also contribute to possible adverse pulmonary effects of phthalates

Changes in life expectancy and disease burden in Norway, 1990–2019: an analysis of the Global Burden of Disease Study 2019

Bill & Melinda Gates FoundationpublishedVersio

Burden of disease attributable to risk factors in European countries: a scoping literature review

Objectives: Within the framework of the burden of disease (BoD) approach, disease, and injury burden estimates attributable to risk factors are a useful guide for policy formulation and priority setting in disease prevention. Considering the important differences in methods, and their impact on burden estimates, we conducted a scoping literature review to: (1) map the BoD assessments including risk factors performed across Europe, and (2) identify the methodological choices in comparative risk assessment (CRA) and risk assessment methods. Methods: We searched multiple literature databases, including grey literature websites, and targeted public health agencies' websites. Results: A total of 113 studies were included in the synthesis and further divided into independent BoD assessments (54 studies) and studies linked to the Global Burden of Disease (59 papers). Our results showed that the methods used to perform CRA varied substantially across independent European BoD studies. While there were some methodological choices that were more common than others, we did not observe patterns in terms of country, year, or risk factor. Each methodological choice can affect the comparability of estimates between and within countries and/or risk factors since they might significantly influence the quantification of the attributable burden. From our analysis, we observed that the use of CRA was less common for some types of risk factors and outcomes. These included environmental and occupational risk factors, which are more likely to use bottom-up approaches for health outcomes where disease envelopes may not be available. Conclusions: Our review also highlighted misreporting, the lack of uncertainty analysis, and the under-investigation of causal relationships in BoD studies. Development and use of guidelines for performing and reporting BoD studies will help understand differences, and avoid misinterpretations thus improving comparability among estimates.info:eu-repo/semantics/publishedVersio

Phthalate exposure and allergic diseases: Review of epidemiological and experimental evidence

Phthalates are among the most ubiquitous environmental contaminants and endocrine-disrupting chemicals. Exposure to phthalates and related health effects have been extensively studied over the past four decades. An association between phthalate exposure and allergic diseases has been suggested, although the literature is far from conclusive. This article reviews and evaluates epidemiological (n = 43), animal (n = 49), and cell culture studies (n = 42), published until the end of 2019, on phthalates and allergic diseases, such as asthma, rhinoconjunctivitis, and eczema. In contrast to earlier reviews, emphasis is placed on experimental studies that use concentrations with relevance for human exposure. Epidemiological studies provide support for associations between phthalate exposures and airway, nasal, ocular, and dermal allergic disease outcomes, although the reported significant associations tend to be weak and demonstrate inconsistencies for any given phthalate. Rodent studies support that phthalates may act as adjuvants at levels likely to be relevant for environmental exposures, inducing respiratory and inflammatory effects in the presence of an allergen. Cell culture studies demonstrate that phthalates may alter the functionality of innate and adaptive immune cells. However, due to limitations of the applied exposure methods and models in experimental studies, including the diversity of phthalates, exposure routes, and allergic diseases considered, the support provided to the epidemiological findings is fragmented. Nevertheless, the current evidence points in the direction of concern. Further research is warranted to identify the most critical windows of exposure, the importance of exposure pathways, interactions with social factors, and the effects of co-exposure to phthalates and other environmental contaminants