Influence of eco-materials on Indoor Air Quality

A growing strategy to reduce the energy consumption of buildings involves a combination of increased air tightness and high levels of insulation. However, an undesirable consequence of this approach is a deterioration of the Indoor Air Quality and accumulation of airborne pollutants, resulting from the reduction in ventilation. The chemical nature and concentration of indoor air pollutants is dependent on the building materials and activities of the occupiers. Recent studies have raised awareness of the effect of Indoor Air Quality on the perceived comfort levels, health and well-being of humans. This paper investigates the role of commercially available natural building materials including lime mortars, natural fibres and wood panels on the Indoor Air Quality. Initially the emissions of Volatile Organic Compounds (VOCs) from building materials were identified and measured. Subsequent tests then considered the adsorption and re-emission behaviour of four VOCs; toluene, limonene, dodecane and formaldehyde. The significance of this paper lies in its demonstration that emissions are dependent on the chemical composition of building materials and the production process, whereas the adsorption/desorption characteristics are related to material microstructure and polarity of the VOCs. The results allow the performance of a construction material, in terms of its influence on indoor air quality, to be deduced from a knowledge of chemical composition and microstructure. This paper provides a new approach for assessing the influence of different building materials on indoor air quality when exposed to gaseous pollutants

Impact of the envelope geometry on cooling demand in very airtight UK dwellings under current and future weather projections

© 2014 The Author. The Passivhaus strategy employs super insulation to reduce the heat transfer through the building envelope. It has been argued that super insulated homes are vulnerable to summer overheating risks, even in the current climate. The UK is expected to experience hotter and more extreme summers in the coming decades and the risk of buildings overheating may become very significant in future climate scenarios. The Passivhaus approach can use much of the solar energy from its relatively large glazing in south facade but this large glazing may eventually lead to overheating in summer time. The study used parametric design modelling to generate differently inclined facade geometries for south elevations. Each elevation was then simulated by means of dynamic building simulation software in order to examine to what extend inclined wall mitigate summer overheating risk for Passivhaus dwellings in the UK under alternative future weather projections

Influence of eco-materials on Indoor Air Quality

This paper investigates the role of commercially available natural building materials, including lime mortars, natural fibres and wood panels on the indoor air quality. Initially, the emissions of volatile organic compounds (VOCs) from building materials were identified and measured. Subsequent tests then considered the adsorption and re-emission behaviour of four VOCs: toluene, limonene, dodecane and formaldehyde. The significance of this paper lies in its demonstration that emissions are dependent on the chemical composition of building materials and the production process, whereas the adsorption/desorption characteristics are related to the material microstructure and the polarity of the VOCs. The results allow the performance of a construction material, in terms of its influence on indoor air quality, to be deduced from knowledge of chemical composition and microstructure. This paper provides a new approach to assessing the influence of different building materials on indoor air quality when they are exposed to gaseous pollutants. </jats:p

Measurement and analysis of air quality in temporary shelters on three continents

Millions of displaced people are housed in shelters that generally consist of a single room, meaning that activities including cooking, sleeping and socializing all take place in the same space. Therefore, indoor air quality can be poor, resulting in estimated 20,000 displaced people dying prematurely every year. Very few studies considered the issue and all within one country. This paper describes the first comprehensive study investigating air quality in shelters by looking at Volatile Organic Compounds (VOCs), Particulate Matter (PM), and CO2 in ten locations within Peru, Ethiopia, Djibouti, Jordan, Turkey and Bangladesh. It has the aim of: (i) discovering how widespread the issue is, (ii) identifying some of the causes, (iii) whether it is linked to cultural and behavioural factors, (iv) location and climate, or (v) shelters’ materials or design. Results revealed very harmful levels of pollutants that are often linked to excess mortality - with total VOC concentrations as high as 102400 µgm-3 and PM over 3000 µgm-3. The reasons for these concentrations were complex, multifaceted and setting-specific. However, it was an issue in both simple self-built shelters and mass-manufactured designs, and across all climates and cultures. In all cases, conditions could be greatly improved by improving airflow as windows were frequently blocked for various reasons. Therefore, airflow should be explicitly considered, whilst being cognisant of the local context; and when cooking is likely to occur indoors, chimneys must be fitted

Measurement and analysis of air quality in temporary shelters on three continents

Millions of displaced people are housed in shelters that generally consist of a single room, meaning that activities including cooking, sleeping and socialising all take place in the same space. Therefore, indoor air quality can be poor, resulting in estimated 20,000 displaced people dying prematurely every year. Very few studies considered the issue and all within one country. This paper describes the first comprehensive study investigating air quality in shelters by looking at Volatile Organic Compounds (VOCs), Particulate Matter (PM), and CO2 in ten locations within Peru, Ethiopia, Djibouti, Jordan, Turkey and Bangladesh. It has the aim of: (i) discovering how widespread the issue is, (ii) identifying some of the causes, (iii) whether it is linked to cultural and behavioural factors, (iv) location and climate, or (v) shelters’ materials or design. Results revealed very harmful levels of pollutants that are often linked to excess mortality - with total VOC concentrations as high as 102400μgm-3 and PM over 3000μgm-3. The reasons for these concentrations were complex, multifaceted and setting-specific. However, it was an issue in both simple self-built shelters and mass-manufactured designs, and across all climates and cultures. In all cases, conditions could be greatly improved by improving airflow as windows were frequently blocked for various reasons. Therefore, airflow should be explicitly considered, whilst being cognisant of the local context; and when cooking is likely to occur indoors, chimneys must be fitted

Properties of bio-based insulation materials and their potential impact on indoor air quality

Significantly decreasing energy consumption in buildings requires more air-tight construction combined with much higher insulation levels. A potential unintended consequence of this approach has been deterioration in the indoor air quality, resulting from significantly reduced ventilation rates and the accumulation of airborne pollutants, and this has proven to be a bottleneck to successful implementation of legislation. The use of natural bio-based insulation materials has increased in recent years, largely driven by concerns over the embodied energy and whole-life environmental impact of insulation materials. This has led to their increased use, typically within breathable wall constructions. A breathable wall construction allows the insulation material to directly contribute to the indoor air quality.Volatile Organic Compounds (VOCs) having boiling points within the range 60-280 °C contribute to the indoor air contamination in buildings, and at certain concentrations can contribute to building-related illnesses. This paper presents some findings from the early stages of a phased experimental study to explore use of bio-based insulation materials, including hemp-lime and sheep’s wool, to reduce VOCs from the room atmosphere. There are many different volatile organic compounds and this study will consider the Total Volatile Organic Compound (TVOC) emissions expressed as toluene, as well as the formaldehyde emissions separately.Insulation specimens with nominal dimensions 200 x 60 x 50 mm were prepared and placed in horizontally mounted cylindrical chambers. Air maintained at 23 °C (±2 °C) and 50 % (±5 %) RH was fed in coaxially to one end of the cylinder. The exhaust air was sampled for VOCs and for formaldehyde following 3 and 28 day of exposure. The results of this paper will help inform the design of holistic indoor environments that consider more than just the hygrothermal properties of insulation materials

Bio-based plaster for improved indoor air quality

People in industrialised countries spend approximately 80% of their time indoors. As such, the internal environment quality can have a significant impact on occupant health and wellbeing. Additionally, the demand for increased building energy efficiency has the potential to degrade Indoor Air Quality (IAQ) through a reduction of air exchange rates. In many forms of construction, the walls and ceilings are plastered, providing a large surface area exposed to the indoor environment. There is a growing recognition of the important role this surface may have on IAQ through regulation of relative humidity. Another, less well known, impact is that porous coatings have the potential to adsorb Volatile Organic Compounds (VOCs) from the air, which offers further potential to improve IAQ.This paper presents work from the development of a novel bio-based plaster with improved hygrothermal performance and VOC sorption characteristics. Cellulose flakes, used for blown insulation, were added into a cement-lime substrate in three different proportions. A range of mechanical, hygrothermal, VOC emission and VOC adsorption properties were investigated to evaluate the potential of the bio-based cement-lime plaster to improve IAQ. The bio-based cement-lime plaster resulted in an improved thermal conductivity and an improvement in the material’s moisture buffering capacity and VOC adsorption capacity. With 5% addition of cellulose flakes, the hygrothermal performance increased by over 25%. This material also showed the ability to capture VOCs and formaldehyde from the air, reducing the concentrations of these compounds by up to 22% and 70 % respectively. Therefore, the impact of the implementation of this plaster includes potential benefits regarding better operational performance of the building and improved occupant health and wellbeing.<br/

Indoor Air Quality

This is a report from the Air Quality Expert Group to the Department for Environment, Food and Rural Affairs; Scottish Government; Welsh Government; and Department of Agriculture, Environment and Rural Affairs in Northern Ireland, on indoor air quality in the UK. The information contained within this report represents a review of the understanding and evidence available at the time of writing

Co-Design of a Trustworthy AI System in Healthcare: Deep Learning Based Skin Lesion Classifier

This paper documents how an ethically aligned co-design methodology ensures trustworthiness in the early design phase of an artificial intelligence (AI) system component for healthcare. The system explains decisions made by deep learning networks analyzing images of skin lesions. The co-design of trustworthy AI developed here used a holistic approach rather than a static ethical checklist and required a multidisciplinary team of experts working with the AI designers and their managers. Ethical, legal, and technical issues potentially arising from the future use of the AI system were investigated. This paper is a first report on co-designing in the early design phase. Our results can also serve as guidance for other early-phase AI-similar tool developments.</jats:p