Acute Cardiovascular Effects of Controlled Exposure to Dilute Petrodiesel and Biodiesel Exhaust in Healthy Volunteers: A Crossover Study

Abstract Background Air pollution derived from combustion is associated with considerable cardiorespiratory morbidity and mortality in addition to environmental effects. Replacing petrodiesel with biodiesel may have ecological benefits, but impacts on human health remain unquantified. The objective was to compare acute cardiovascular effects of blended and pure biodiesel exhaust exposure against known adverse effects of petrodiesel exhaust (PDE) exposure in human subjects. In two randomized controlled double-blind crossover studies, healthy volunteers were exposed to PDE or biodiesel exhaust for one hour. In study one, 16 subjects were exposed, on separate occasions, to PDE and 30% rapeseed methyl ester biodiesel blend (RME30) exhaust, aiming at PM10 300 μg/m3. In study two, 19 male subjects were separately exposed to PDE and exhaust from a 100% RME fuel (RME100) using similar engine load and exhaust dilution. Generated exhaust was analyzed for physicochemical composition and oxidative potential. Following exposure, vascular endothelial function was assessed using forearm venous occlusion plethysmography and ex vivo thrombus formation was assessed using a Badimon chamber model of acute arterial injury. Biomarkers of inflammation, platelet activation and fibrinolysis were measured in the blood. Results In study 1, PDE and RME30 exposures were at comparable PM levels (314 ± 27 μg/m3; (PM10 ± SD) and 309 ± 30 μg/m3 respectively), whereas in study 2, the PDE exposure concentrations remained similar (310 ± 34 μg/m3), but RME100 levels were lower in PM (165 ± 16 μg/m3) and PAHs, but higher in particle number concentration. Compared to PDE, PM from RME had less oxidative potential. Forearm infusion of the vasodilators acetylcholine, bradykinin, sodium nitroprusside and verapamil resulted in dose-dependent increases in blood flow after all exposures. Vasodilatation and ex vivo thrombus formation were similar following exposure to exhaust from petrodiesel and the two biodiesel formulations (RME30 and RME100). There were no significant differences in blood biomarkers or exhaled nitric oxide levels between exposures. Conclusions Despite differences in PM composition and particle reactivity, controlled exposure to biodiesel exhaust was associated with similar cardiovascular effects to PDE. We suggest that the potential adverse health effects of biodiesel fuel emissions should be taken into account when evaluating future fuel policies. Trial registration ClinicalTrials.gov, NCT01337882 /NCT01883466. Date of first enrollment March 11, 2011, registered April 19, 2011, i.e. retrospectively registered

Photocatalytic Decomposition of Formic Acid on Mo2C-Containing Catalyst

Soluble components in the peripheral blood from experimental exposure of 14 healthy subjects to filtered air and wood smoke. Samples were collected before (pre), at 24 h and 44 h after exposure, to air and wood smoke. Data are given as medians with interquartile range. (DOCX 62 kb

Discourse and religion in educational practice

Despite the existence of long-held binaries between secular and sacred, private and public spaces, school and religious literacies in many contemporary societies, the significance of religion and its relationship to education and society more broadly has become increasingly topical. Yet, it is only recently that the investigation of the nexus of discourse and religion in educational practice has started to receive some scholarly attention. In this chapter, religion is understood as a cultural practice, historically situated and embedded in specific local and global contexts. This view of religion stresses the social alongside the subjective or experiential dimensions. It explores how through active participation and apprenticeship in culturally appropriate practices and behaviors often mediated intergenerationally and the mobilisation of linguistic and other semiotic resources but also affective, social and material resources, membership in religious communities is constructed and affirmed. The chapter reviews research strands that have explored different aspects of discourse and religion in educational practice as a growing interdisciplinary field. Research strands have examined the place and purpose of religion in general and evangelical Christianity in particular in English Language Teaching (ELT) programmes and the interplay of religion and teaching and learning in a wide range of religious and increasingly secular educational contexts. They provide useful insights for scholars of discourse studies to issues of identity, socialisation, pedagogy and language policy

Effect of wood smoke exposure on vascular function and thrombus formation in healthy fire fighters

Background: Myocardial infarction is the leading cause of death in fire fighters and has been linked with exposure to air pollution and fire suppression duties. We therefore investigated the effects of wood smoke exposure on vascular vasomotor and fibrinolytic function, and thrombus formation in healthy fire fighters. Methods: In a double-blind randomized cross-over study, 16 healthy male fire fighters were exposed to wood smoke (~1 mg/m3 particulate matter concentration) or filtered air for one hour during intermittent exercise. Arterial pressure and stiffness were measured before and immediately after exposure, and forearm blood flow was measured during intra-brachial infusion of endothelium-dependent and -independent vasodilators 4–6 hours after exposure. Thrombus formation was assessed using the ex vivo Badimon chamber at 2 hours, and platelet activation was measured using flow cytometry for up to 24 hours after the exposure. Results: Compared to filtered air, exposure to wood smoke increased blood carboxyhaemoglobin concentrations (1.3% versus 0.8%; P &lt; 0.001), but had no effect on arterial pressure, augmentation index or pulse wave velocity (P &gt; 0.05 for all). Whilst there was a dose-dependent increase in forearm blood flow with each vasodilator (P &lt; 0.01 for all), there were no differences in blood flow responses to acetylcholine, sodium nitroprusside or verapamil between exposures (P &gt; 0.05 for all). Following exposure to wood smoke, vasodilatation to bradykinin increased (P = 0.003), but there was no effect on bradykinin-induced tissue-plasminogen activator release, thrombus area or markers of platelet activation (P &gt; 0.05 for all). Conclusions: Wood smoke exposure does not impair vascular vasomotor or fibrinolytic function, or increase thrombus formation in fire fighters. Acute cardiovascular events following fire suppression may be precipitated by exposure to other air pollutants or through other mechanisms, such as strenuous physical exertion and dehydration.Originally included in thesis in manuscript form.</p

The influence of combustion conditions on flue gas particle composition in a modified pellets stove

I två översiktsartiklar har ledande europeiska och amerikanska forskare slagit fast att partiklar i emissioner från vedeldning och utsläpp vid småskalig biobränsleeldning generellt sett måste anses som skadligt för hälsan vid exponering, även i de låga halter som normalt förekommer i utomhusluften. Vad som dock saknas är kunskap kring hur denna "farlighet" förändras, och kan påverkas, då modern teknik används samt hur olika biobränslen förhåller sig i detta sammanhang. Med avseende på detta så genomfördes detta examensarbete i syfte att fastställa hur olika förbränningsförhållanden i en modifierad pelletskamin inverkar på rökgaspartiklarnas sammansättning m a p organiskt och elementärt kol. Vidare undersöktes om det är möjligt att stabilt generera en "sotande" förbränning under längre perioder för framtida toxikologiska studier av rökgaser från biomassa. Resultaten visar på att det är möjligt att med hjälp av de parametrar som funnits att variera, stabilt kunna generera olika sorters förbränningstyper i den nu använda och modifierade pelletskaminen där såväl totalhalten partiklar som fördelningen av organiskt och elementärt kol i partiklarna varierade. Detta är lovande och visar på att det på ett kontrollerat vis går att skapa emissioner under ofullständiga förbränningsförhållanden där partiklarna har olika karakteristik. För att genomföra mer ingående studier rekommenderas dock att vissa förbättringar och utveckling av tekniken genomförs, för ökad kontroll och flexibilitet. Detta kan antingen ske med en ombyggd (enligt de förslag som ges i felkällor) pelletskamin (t ex Pitekaminen), alternativt en helt ny egendesignad reaktor/kamin. Detta för att kunna verifiera de resultat som fåtts innan någon omfattande studie kring partikelegenskaper grundas på de resultat som nåtts i detta arbete. En aspekt är att det i befintliga system (kaminer m m) är svårt att elda pellets "kallt", och generera pyrolysprodukter, eftersom pellet är ett torrt bränsle och det matas in på en het/glödande bränslebädd. För att komma runt detta, men fortfarande nyttja fördelarna med kontinuerligt matad pellets, behövs troligen en helt annan design av förbränningsutrymmet där en "primär-zon" pyrolyserar bränslet innan koksförbränningen sker vid högre temperatur.In two review articles leading European and American researchers have stated that particles in emissions from residential wood combustion and emissions from small-scale biomass burning in general must be regarded as harmful to health during exposure, even in the low concentrations normally found in outdoor air. However, what is missing is knowledge about how this toxicity changes and may be affected when modern combustion technology is used and how different biomass fuels relate in this context. Because of this, the objective with this work was to determine the influence of combustion conditions in a modified pellet stove on the composition of particulate matter in the emissions with respect to the distribution of organic and elemental carbon. A further purpose was to investigate whether it is possible to generate a stable "sooty" burning state for longer periods of time to be used in future toxicological studies of biomass emission particles. The results showed that it is possible, by adjusting the parameters that was available, to generate stable conditions of different types of combustion in the currently used and modified pellet stove. Both the total mass concentration of particles and the distribution of organic and elemental carbon in the particulate matter varied. This is promising and shows that it is possible to create, in a controlled manner, incomplete combustion conditions where the particles have different characteristics and properties. In order to conduct more detailed studies, however, it is recommended that certain improvements and development of technology is implemented, to enable better control and flexibility. This can be done either with a rebuilt pellet stove or a completely new self-designed reactor. This should be applied to verify the results obtained before any comprehensive study on particle properties based on the results achieved in this work is performed

Design and evaluation of an experimental setup for human exposure studies of emissions from biomass combustion.

Ledande europeiska och amerikanska forskare har slagit fast att partiklar i emissioner från vedeldning ("vedrök") och utsläpp vid småskalig biobränsleeldning generellt sett måste anses som skadligt för hälsan vid exponering, även i de låga halter som normalt förekommer i utomhusluften. Vad som dock saknas är kunskap kring hur denna "farlighet" förändras, och kan påverkas, då modern teknik används samt hur olika biobränslen förhåller sig i detta sammanhang. Skälet till att det är så viktigt med forskning inom området är eftersom det är beslutat i Europeiska Unionen att 2020 skall 20% av medlemsnationernas energibehov komma från förnyelsebara bränslen. Redan nu är det känt att stora delar av PM2,5 kommer från biomassaförbränning, främst småskalig sådan, och därav behövs forskning om vilka tekniker som har minst negativa effekter så att rätt teknik väljs när EU målet uppnås. Ett bra sätt att undersöka dessa frågeställningar är genom s.k. humanexponeringar där människor på ett kontrollerat vis exponeras för olika typer luftburna föroreningar, t ex vedrök och dieselavgaser. Syftet med detta examensarbete var därför att konstruera, utvärdera och undersöka olika delar och frågeställningar kopplat till ett sådant humanexponeringssystem vid ETPC, Umeå universitet. Under de tester som genomfördes i slutet av arbetet så visade det sig att systemet fungerar som det ska och att det går med lite erfarenhet av systemet att genomföra repeterbara försök i laborationsuppställningen i sin helhet. De problem som stöttes på var bland annat utspädningen av rökgaserna men till slut så hittades SEC100 som klarade de krav som ställs och med regelbundet underhåll så finns det inget som talar för att det kommer uppstå några problem med framtida exponeringar när denna används under samma förhållanden som under detta arbete. Ett annat problem var Omblandningen i kammaren som inte är perfekt, det var en viss skillnad i koncentration i de olika hörnen av kammaren, men utifrån de förutsättningar som fanns uppfylls de krav som ställts och systemet i sin helhet har under upprepade exponeringar visat sin duglighet.Leading European and U.S. researchers have concluded that fine particles in emissions from burning wood ("wood smoke") and emissions from small-scale biomass burning in general must be regarded as harmful to health, even in the low concentrations normally found in outdoor air. However, what is lacking is knowledge about how this health risk is changing, and may be affected, when modern technology is used and how different biofuels relate in this context. The reason it is so important to do research in the area is because it is decided in the European Union that in 2020, 20% of the member nations energy needs will come from renewable fuels. It is already known that large parts of PM2,5 derives from biomass combustion (mainly small scale) and hence the need for research on what technologies that have the least negative effects so that the correct technology is chosen on the way to the goal. An important method to explore these issues is through controlled human exposures where different kinds of air pollution components can be used, e g wood smoke and diesel exhaust. The objective with this master thesis was therefore to construct, evaluate and elucidate different component is such an exposure set-up at ETPC, Umeå university.es. The control system has been tested and evaluated over several exposures and have fulfilled all the requirements set at the beginning of the work. During the tests conducted at the end of the work it turned out that the system is working properly and that it is possible with a little experience of the system to conduct repeatable experiments in the setup in its entirety. One of the problems encountered was the dilution of flue gases but when the ejector SEC100 was found it passed the requirements and with regular maintenance, there are no indications that there will be any problems with future exposures when used under the same conditions as during this work. Mixing in the chamber is not perfect but on the conditions that existed it met the requirements set and the system as a whole has during repeated exposures shown that it also fulfills all the requirements set at the beginning

Particle emissions from residential wood and biodiesel combustion

Emissions from anthropogenic combustion sources, such as vehicles and biomass combustion, contribute significantly to ambient particulate matter (PM) both on a local and global scale. Exposure to ambient PM and air pollution in general is linked to a variety of different health effects and it has been estimated that as many as 2.1 million premature deaths each year, due to cardiopulmonary disease and lung cancer, are caused by the changes in anthropogenic air pollution since pre-industrial times. There is today still a lack of information regarding the emissions of different specific particulate emission components, e.g. soot, polycyclic aromatic hydrocarbons (PAHs), oxy-PAHs combined with details about the behaviour of different fuels under varying combustion conditions. The overall objective of this work was to provide new knowledge regarding physical and chemical properties of PM from solid and liquid biofuels, which are important for the viewpoint of human health and atmospheric pollution. This was achieved by experimental studies of the combustion of biomass using a residential wood stove and by introducing biodiesel to an off-road engine, thereby investigating two major emission sources for PM and gaseous emissions. From the two papers regarding biodiesel included in this thesis, it can be concluded that the introduction of the biodiesel, and potentially other renewable fuels, can in a considerable way change the exhaust particle emissions. This could have implications for the assessment of exhaust from engines running on biodiesel fuels, especially when introducing biodiesel in existing and older engines. The results from the wood combustion research performed showed some important considerations regarding both specific particle properties and the influences of different burning conditions and fuels. One major finding, based on several of the included studies, was that a proper operation of a wood stove is of major importance to avoid unfavourable burning condition and elevated emissions of soot and organic particles, regardless of the wood species used. Some specific occasions during the burning phases in batch wise wood combustion were also identified as important for the overall emissions. The results from this research has given new specific insights into the emissions from wood stoves and should be of relevance for both technological development of residential appliances, emission testing/certification, information to users and legislation