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Showing posts from May, 2019

CO2 in the Home

CO2 monitors of useful accuracy are available at modest price, and the information they provide about air quality in the home can be used in different ways.
A first question in response to a home CO2 reading might be about its health implications. This issue is addressed by Usha Satish et al. in their 2012 paper
Is CO2 an Indoor Pollutant? Direct Effects of Low-to-Moderate CO2 Concentrations on Human Decision-Making Performance [1]
The writers point out that it has been thought that adverse effects attributed to raised CO2 levels in the home are actually due to other pollutants commonly associated with CO2. They describe how their experiment was designed to eliminate this possibility and so isolate the effects of CO2.
Before presenting their own findings, they summarise previous research on levels of CO2 much higher than those likely to be encountered in the home: “CO2 concentrations > 20,000 ppm cause deepened breathing; 40,000 ppm increases respiration markedly; 100,000 ppm causes…

Indoor Air Quality

Three main groups of pollutant have been distinguished as affecting indoor air quality.
According to Schieweck et al., [1] they are outdoor air pollutants, occupant-related pollutants, and building-related pollutants. Those entering a building from outside include carbon monoxide (CO), benzene (C6H6), sulphur dioxide (SO2), ozone (O3), oxides of nitrogen(NO, NO2), and particles. Pollutants mainly produced by occupants include CO2, bio-effluents and particulate matter. Those originating from the materials used in building construction, furnishing and indoor equipment are typically volatile organic compounds, and also viruses, fungi and bacteria.
The levels of such pollutants may clearly be important to the health of occupants, but are of particular concern if energy saving measures are taken which may increase the concentration of any pollutants by reducing ventilation levels. Such measures are of interest to many Community Energy groups in the UK, where domestic heating efficiency is a ma…

A Change of Air

Energy saving, ventilation and health.
In the UK an appreciable proportion of total energy consumption can be ascribed to heating buildings, and of this energy a significant amount is used to heat air. If the number of air changes per hour (ACH) is unnecessarily high, energy is wasted. This post concentrates on domestic buildings, in which a reduction in ACH can often be achieved by cheap and simple means, giving a rapid return on expenditure through lowered energy costs. However, the ACH figure for a house should not be reduced below the minimum needed for the health of its occupants and the preservation of its fabric. In order to know whether the ACH for a dwelling should be reduced, the actual ACH value is needed, and to know by how much it can safely be cut, the minimum figure is required.
Pressurisation is one method of measuring the actual ACH figure, and is described in ATTMA Technical Standard L1 Measuring Air Permeability in the Envelopes of Buildings, 2016 (open access). Press…

Community Renewable Energy in the UK

The impact of policy changes: The opportunities of Community Renewable Energy projects in the UK and the barriers they face
Pegah Mirzania, Andy Ford, Deborah Andrews, George Ofori, Graeme Maidment
Energy Policy 129 (2019) 1282–1296
The role of Community Renewable Energy (CRE) is reviewed in the context of the energy trilemma (the problem of delivering energy security, equity, and environmental sustainability), changing policy, and the UK’s aging infrastructure. The paper is based on information gathered from community energy groups during 2016 and 2017. It describes the “huge problems” that arose following changes in government policy, and concludes with recommendations on future policy and on business models.
Key points in the early development of government policy on CRE are reviewed, the growth of the sector is compared with that achieved in other European countries, and a series of later policy changes are listed which were detrimental to the prospects of CRE.
The paper discusses ways…