UK apartment construction impact on carbon life cycle calculations

There is no fixed method to analyse the global warming (carbon) impact of a building envelope over its life time, however guidance is given in BS EN 15978 [1]. The paper assesses the Life Cycle stages and components in 3 archetypal construction typologies for an apartment building assessed with the BRE Green Guide [2] as a comparator. There is a difference of a factor of 4 between construction types and the position of units within an apartment block. Replacement and recycling factors significantly affect the end results with steel being highly recyclable, concrete advantageous in longevity and timber sequestering carbon at early stages. Timber does have an increased number of replacements during the life span and significant impacts at end of life stages. The BRE quantification does not take into account foundations leading to a climate change impact 3 times lower than a bottom up analysis for a steel building

Toxicidade de prata, chumbo e nanoplásticos em diferentes estádios de desenvolvimento de anfíbios

Over the last 40 years amphibian populations are reported to be increasingly declining each year with amphibian species disappearing completely from their natural place of occurrence. This decline is mostly due to anthropogenic disturbances and the negative effects they pose to this group of vertebrates. Amphibians are considered very sensitive to environmental changes, namely because they are characterized by a highly permeable skin. Until recently, the risk assessment of chemicals for amphibians was based on the data generated for fish (for aquatic life stages) and for birds and mammals (for terrestrial life stages). However, it has been reported that the use of data from these three groups of vertebrates may underestimate the risk of some chemicals to amphibians. It is, therefore needed to generate toxicity data specifically for amphibians in order to promote its accurate protection and conservation. The present study aimed at assessing the toxicity of two metals and a nanoplastic to aquatic early life stages of an amphibian species. It also intended to assess the adequacy of using in vitro assays, with amphibian cell lines, as surrogates of the in vivo assays to assess the toxicity of the selected chemicals to this group of organisms. To attain these objectives the anuran Xenopus laevis was used as test model species. Embryos and tadpoles of X. laevis were exposed to a set of concentrations of silver, lead or nanoplastics of polystyrene and the following endpoints were monitored: for embryos – mortality, malformations, hatching rate and body length; and for tadpoles – mortality, growth rate (as weight gain and body length increase), developmental stage, and heart beat rate. Lead concentrations equal or above 0.22 mg/L induced significant adverse effects in the hatching rate and snout-to-vent length of larvae exposed to lead since the embryonic stage. Tadpoles exposed to concentrations of lead equal or above 0.49 mg/L showed significant changes in the weight gain and total body growth rate. The in vitro assays with lead revealed a significant reduction of cells viability at concentrations equal or higher than 0.078 mg/L. Regarding silver, concentrations as low as 0.013mg/L induced the appearance of malformations, an early hatching and increased snout-to-vent length of larvae. This same concentration induced an increase in the tail and total body growth rates. The in vitro assay revealed to be very sensitive to silver, concentrations as low as 0.0004 mg/L of silver affected negatively the viability of cells. Nanoparticles of polystyrene induced no significant effects on both embryos and tadpoles. Overall, the embryos and tadpoles of X. laevis exhibited a similar sensitivity to the tested chemicals. The in vitro assays performed with lead, revealed that A6 cell lines are slightly more sensitive to lead than embryos or tadpoles of X. laevis. In the case of silver, toxic effects in the cell lines were observed at concentrations much lower than those inducing effects in embryos and tadpoles. The obtained results suggest that for early stages of risk assessment frameworks, in vitro assays may be used for a first toxicity screening in order to avoid running animal experimentation.Nos ultimos 40 anos as populacoes de anfibios tem sofrido um declinio a nivel mundial, tendo sido identificadas especies de anfibios a desaparecer por completo dos locais onde naturalmente ocorrem. Este declinio deve-se principalmente a atividades antropogenicas e aos efeitos negativos que elas podem provocar neste grupo de vertebrados. Os anfibios sao considerados organismos muito sensiveis a alteracoes ambientais, principalmente porque possuem uma pele altamente permeavel. Ate recentemente, a avaliacao de riscos de produtos quimicos para anfibios era baseada em dados ecotoxicologicos gerados para peixes (para estadios de vida aquaticos) e para aves e mamiferos (para estadios de vida terrestres). Contudo, o uso destes dados pode levar a que seja subestimado o risco de certos produtos para os anfibios. Deste modo, tornase fundamental obter dados de toxicidade especificamente gerados para diferentes estadios de desenvolvimento de anfibios, com o intuito de promover a sua protecao e conservacao, de forma precisa. Este estudo teve como objetivo principal avaliar a toxicidade de dois metais e um tipo de nanoplastico para os estadios de vida iniciais aquaticos de uma especie de anfibio, Xenopus laevis. Para alem disso, pretendeu-se avaliar a adequabilidade de ensaios in vitro, com linhas celulares de anfibios, como substitutos de ensaios in vivo para avaliar a toxicidade de produtos quimicos e nanoparticulas para este grupo de organismos. Embrioes e girinos de X. laevis foram expostos a uma gama de concentracoes de prata, chumbo e nanoplasticos de poliestireno, tendo sido avaliados os seguintes parametros: em embrioes – mortalidade, malformacoes, taxa de eclosao, comprimento corporal; e em girinos – mortalidade, taxa de crescimento (ganho de peso e aumento do comprimento do corpo), estadio de desenvolvimento e batimento cardiaco. Concentracoes de chumbo iguais ou superiores a 0.22 mg/L afetaram significativamente a taxa de eclosao e comprimento rostro-cloaca das larvas expostas desde a fase de embriao. No caso dos girinos, foram identificadas alteracoes significativas na taxa de ganho de peso e de crescimento corporal em concentracoes de chumbo iguais ou superiores a 0.49 mg/L. Os ensaios in vitro demonstraram uma reducao da viabilidade celular em concentracoes de chumbo iguais ou superiores a 0,078 mg/L. Em relacao a prata, concentracoes tao baixas como 0.013 mg/L induziram o aparecimento de malformacoes, eclosao precoce e diminuicao do comprimento rostro-cloaca em larvas. Esta mesma concentracao causou um aumento da taxa de crescimento da cauda, e corporal. Os ensaios in vitro apresentaram maior sensibilidade a prata, tendo havido efeitos significativos na viabilidade celular a partir da concentracao de 0.0004 mg/L. A exposicao a nanoparticulas de poliestireno nao induziu efeitos significativos nem em embrioes nem em girinos para concentracoes entre 3,95 e 30 mg/l de poliestireno. Em suma, os embrioes e girinos de X. laevis demostraram uma sensibilidade semelhante aos produtos quimicos testados. Nos ensaios in vitro com celulas A6, os dados obtidos, no caso dos ensaios com chumbo, demonstram que as celulas sao ligeiramente mais sensiveis a este contaminante que os girinos e os embrioes. Nos dados obtidos para a prata, houve efeitos significativos nas celulas, em concentracoes mais baixas que as utilizadas nos ensaios com embrioes e girinos. Estes dados sugerem que, pelo menos para esta linha celular, a prata e muito mais toxica do que o que seria expectavel dos dados dos restantes ensaios. Os resultados obtidos neste estudo sugerem que em estadios iniciais de avaliacao de risco, ensaios in vitro podem ser usados como uma ferramenta sensivel para a avaliacao de toxicidade, tendo o valor acrescentado de permitir evitar a experimentacao em animais.Mestrado em Ecologia Aplicad

Using Passive Strategies to prevent overheating and promote resilient buildings

Overheating is becoming a problem in buildings in the city centre. This situation is further exacerbated by the Urban Heat Island phenomena and by climate change. High levels of urbanisation and design decisions that compromise the use of passive technologies e.g. opening windows, have resulted in more active systems being used for cooling. This has often led to an increase of energy consumption and compromising the need to achieve nearly zero carbon buildings in the near future. This paper assesses the likelihood of a model dwelling in London overheating in line with climatic predictions for the year 2030, 2050 and 2080. The criteria to assess overheating are based on the Technical Memorandum 52 from CIBSE. A range of passive solutions e.g. natural ventilation, shading and orientation are assessed and discussed in a move towards sustainable buildings that are resilient to global warming

Assessment of climate change on UK dwelling indoor comfort

The effect of future climate change may reduce heating load but will significantly increase overheating on a largely naturally cooled dwelling stock in the UK. Thermal mass significantly reduces the need for active cooling to be used. The air conditioning installation date for a range of building characteristics is presented with the amount of overheating occurring in a heat wave. The future weather file for 2080 with 90th percentile data show a large increase in overheating events and is considered too extreme. The need for active cooling in bedrooms is expected to occur around 2035 and is independent of a heat wave. Results for living rooms are more variable with thermal mass mitigating the adoption of active cooling by 40 years and 25% of the overheating in a heat wave event. Designers need to think about thermal mass usage in living rooms to cater for extreme temperature events rather than the whole of the cooling season to delay the adoption of active cooling

The impacts of overheating mitigation within the life cycle carbon of dwellings under UK future climate

Overheating factors are not understood by designers at early design stage both the operation and construction of buildings directly influence when air condition is adopted in dwellings,using TM52 the sensitivity of variables is studied to mitigate overheating events to achieve comfortable buildings. Air velocity, thermal mass and shading are the most influential mitigation factors against overheating but realistic values are required to understand the implications of design choices made.Glazing in the normal range has a low effect on overheating outcome but shading features are required for larger glazed areas to stop excessive solar gain and uncomfortable conditions during occupied hours