Use of portable air purifiers in homes: Operating behaviour, effect on indoor PM2.5 and perceived indoor air quality

In much of the world, people spend on average 65% of their time indoors at home. It is, therefore, important to understand the quality of air in homes, and how best to improve it. Negative health impacts associated with exposure to particulate matter are well documented, and account for significant morbidity and mortality worldwide. Technologies are rapidly being developed and adopted to mitigate indoor air pollution, and portable home air purifiers (HAPs) are one of the most effective technologies available to clean the surrounding air of harmful pollutants of both indoor and outdoor origin. The aims of the research presented here were to explore the impact of a commercially available air purifier used in actual bedrooms on indoor PM2.5 concentrations and perceived indoor air quality, as well as to understand and describe how portable air purifiers are used by occupants. Results from the present study showed that PM2.5 concentrations in bedrooms were reduced by a mean of 45% over 90 min with HAP use. Participants’ subjective assessment of the indoor air when the HAP was on was positive. However, the predominant motivation and indicator of HAP use was thermal comfort, and not perceived air quality. If used properly, portable air purifiers used at home could be effective at reducing exposure to PM2.5 indoors

Capturing the diversity of household window operation behaviour: Lessons from a monitoring campaign in London

The present study benefits from a field monitoring campaign across 18 flats in London to analyse the operation of windows by occupants and pinpoint the driving factors. The dataset covers an extensive set of environmental parameters including indoor and outdoor air temperature, relative humidity, CO2, PM2.5 and PM10 collected over non-heating and heating seasons. Focusing on three questions, this study a) captures the diversity of window operation across the flats using three metrics, b) identifies and ranks the driving factors behind the operation of windows, and c) discusses the diversity of these driving factors using univariate logistic regression models. Notably, the results suggest that, apart from the commonly studied factors such as air temperature and humidity, pollutant parameters can also explain the operation of windows by occupants. Furthermore, the diversity observed in the occupants’ window operation behaviour and its driving factors discourages the reliance of future modelling efforts on aggregated datasets that can suppress the inter-occupant diversity. More efforts are needed to further explore the potential benefits of the inclusion of the captured behavioural diversity information in occupant behaviour models for building performance simulations

An investigation of the influencing factors for occupants' operation of windows in apartments equipped with portable air purifiers

As operations of windows by occupants can greatly affect building energy consumption and indoor air quality, understanding the driving factors of this adaptive control behaviour is of great importance. The present paper reports on an investigation into the influencing factors for window operation behaviour in eighteen newly-built, low-energy apartments in London, UK. A range of indoor and outdoor environmental variables (including temperature, relative humidity, CO2 and particulate matter) as well as the window status (open/closed) were monitored for 6–11 months. About half of the apartments included monitoring for nearly three months during a national pandemic lockdown. Additionally, each apartment was provided with a portable home air purifier (HAP) to use during most of the study period. The effects of environmental variables and the use of HAPs on occupants' operations of windows in the main bedroom were analysed according to different periods (free-running, heating and lockdown period) and occupancy stages (arrival, departure and intermediate occupied times). Results indicated that analysing the heating period alone could lead to explanations of window operation behaviour that were contradictory to those from analysing other periods, and separating the dataset based on different occupancy stages to develop behaviour models was of little value. The results of statistical significance tests showed that indoor temperature was the leading driving factor for occupants’ window opening and closing behaviour, whereas neither air quality-related variables nor the use of air purifiers had a statistically significant impact on window operation behaviour

Towards a framework to evaluate the ‘total’ performance of buildings

Internationally, buildings are a major contributor to carbon emissions. Despite significant advances in the technology and construction of energy-efficient buildings, in many cases a performance gap between designed and actual performance exists. While much research has investigated the drivers of the building energy performance gap – both static and transient– there has been considerably less research into the total performance gap, defined here as performance gaps in building energy use, occupant satisfaction and Indoor Environmental Quality parameters such as thermal comfort and air quality which may impact on occupant health and wellbeing. This paper presents a meta-analysis of building performance data from buildings in the UK and China – selected due to their contrasting development environments – which illustrate the presence of and complexities of evaluating total performance gaps in both countries. The data demonstrate the need for (1) high end-use, spatial granularity and temporal resolution data for both energy and Indoor Environmental Quality, and (2) developing methodologies that allow meaningful comparisons between buildings internationally to facilitate learning from successful building design, construction methodologies and policy environments internationally. Using performance data from a UK building, a potential forward path is illustrated with the objective of developing a framework to evaluate total building performance. Practical application: While much research has examined building energy performance gaps, Indoor Environmental Quality and occupant satisfaction gaps are rarely included despite their relationship to energy. We use a meta-analysis of energy, indoor environmental quality, and occupant satisfaction data from buildings in the UK and China to illustrating the presence of and complexities of evaluating total performance gaps for buildings in the two countries, and the need for high resolution dynamic buildings data and novel methodologies for comparison between buildings across different contexts. Illustrative case studies are used to demonstrate potential future directions for evaluating ‘total’ building performance

Bridging the Gap: the need for a systems thinking approach in understanding and addressing energy and environmental performance in buildings

Innovations in materials, construction techniques and technologies in building construction and refurbishment aim to reduce carbon emissions and produce low-energy buildings. However, in-use performance consistently misses design specifications, particularly those of operational energy use and indoor environmental quality. This performance gap risks reducing design, technology, sustainability, economic, health and well-being benefits. In this paper, we compare settings of the Chinese and the UK buildings sectors and relate their historical context, design, construction and operation issues impacting energy performance, indoor environmental quality, occupant health and well-being. We identify a series of key, common factors of ‘total’ building performance across these two settings: the application of building regulations, the balance between building cost and performance, skills, construction and operation. The dynamic and complex interactions of these factors are currently poorly understood and lead to building performance gaps. We contend that a systems approach in the development of suitable building assessment methods, technologies and tools could enable the formulation and implementation of more effective policies, regulations and practices. The paper illustrates the application of the approach to the UK and Chinese settings. A full application of a systems approach may help to provide a more dynamic understanding of how factor interactions impact the ‘total’ building performance gaps and help address its multiple causes

Evidence for Neutrino Oscillations from Muon Decay at Rest

A search for nu_bar_mu to nu_bar_e oscillations has been conducted at the Los Alamos Meson Physics Facility using nu_bar_mu from mu+ decay at rest. The nu_bar_e are detected via the reaction (nu_bar_e,p) -> (e+,n), correlated with the 2.2 MeV gamma from (n,p) -> (d,gamma). The use of tight cuts to identify e+ events with correlated gamma rays yields 22 events with e+ energy between 36 and 60 MeV and only 4.6 (+/- 0.6) background events. The probability that this excess is due entirely to a statistical fluctuation is 4.1E-08. A chi^2 fit to the entire e+ sample results in a total excess of 51.8 (+18.7) (-16.9) (+/- 8.0) events with e+ energy between 20 and 60 MeV. If attributed to nu_bar_mu -> nu_bar_e oscillations, this corresponds to an oscillation probability (averaged over the experimental energy and spatial acceptance) of 0.0031 (+0.0011) (-0.0010) (+/- 0.0005).Comment: 57 pages, 34 figures, revtex, additional information available at http://nu1.lampf.lanl.gov/~lsnd

Parental cultural models and resources for understanding mathematical achievement in culturally diverse school settings

This paper proposes that the theoretical concept of cultural models can offer useful insights into parental involvement in their child’s mathematical achievement and the resources they use to go about gaining information in culturally diverse learning settings. This examination takes place within a cultural-developmental framework and draws on the notion of cultural models to explicate parental understandings of their child’s mathematics achievement and what resources are used to make sense of this. Three parental resources are scrutinized: (a) the teacher, (b) examination test results, and (c) constructions of child development. The interviews with 22 parents revealed some ambiguity around the interpretation of these resources by the parent, which was often the result of incongruent cultural models held between the home and the school. The resources mentioned are often perceived as being unambiguous but show themselves instead to be highly interpretive because of the diversity of cultural models in existence in culturally diverse settings. Parents who are in minority or marginalized positions tend to have difficulties in interpreting cultural models held by school, thereby disempowering them to be parentally involved in the way the school would like

'Prove me the bam!': victimization and agency in the lives of young women who commit violent offences

This article reviews the evidence regarding young women’s involvement in violent crime and, drawing on recent research carried out in HMPYOI Cornton Vale in Scotland, provides an overview of the characteristics, needs and deeds of young women sentenced to imprisonment for violent offending. Through the use of direct quotations, the article suggests that young women’s anger and aggression is often related to their experiences of family violence and abuse, and the acquisition of a negative worldview in which other people are considered as being 'out to get you' or ready to 'put one over on you'. The young women survived in these circumstances, not by adopting discourses that cast them as exploited victims, but by drawing on (sub)cultural norms and values which promote pre-emptive violence and the defence of respect. The implications of these findings for those who work with such young women are also discussed

Evidence for νˉμ→νˉe\bar\nu_\mu\to\bar\nu_e Oscillations from the LSND Experiment at LAMPF

A search for $\bar\nu_{\mu}\to \bar\nu_{e}$ oscillations has been conducted at the Los Alamos Meson Physics Facility by using $\bar\nu_\mu$ from $\mu^+$ decay at rest. The $\bar\nu_e$ are detected via the reaction $\bar\nu_e\,p \rightarrow e^{+}\,n$, correlated with a $\gamma$ from $np\rightarrow d\gamma$ ($2.2\,{\rm MeV}$). The use of tight cuts to identify $e^+$ events with correlated $\gamma$ rays yields 22 events with $e^+$ energy between 36 and $60\,{\rm MeV}$ and only $4.6 \pm 0.6$ background events. A fit to the $e^+$ events between 20 and $60\,{\rm MeV}$ yields a total excess of $51.8^{+18.7}_{-16.9} \pm 8.0$ events. If attributed to $\bar \nu_\mu \rightarrow \bar \nu_e$ oscillations, this corresponds to an oscillation probability of ($0.31^{+0.11}_{-0.10} \pm 0.05$)\%.Comment: 4 pages, 3 figures, revtex, psfig. additional information available at http://nu1.lampf.lanl.gov/~lsnd

Candidate Events in a Search for Muon Antineutrino to Electron Antineutrino Oscillations

A search for \nuebar's in excess of the number expected from conventional sources has been made using the Liquid Scintillator Neutrino Detector, located 30 m from a proton beam dump at LAMPF. A \nuebar signal was detected via the reaction \nuebar\,p \rightarrow e^{+}\,n with $e^+$ energy between 36 and 60\mev, followed by a $\gamma$ from $np\rightarrow d\gamma$ (2.2\mev). Using strict cuts to identify $\gamma$'s correlated with positrons results in a signal of 9 events, with an expected background of $2.1 \pm 0.3$. A likelihood fit to the entire $e^+$ sample yields a total excess of $16.4^{+9.7}_{-8.9}\pm 3.3$ events, where the second uncertainty is systematic. If this excess is attributed to neutrino oscillations of the type \numubar\rightarrow\nuebar, it corresponds to an oscillation probability of ($0.34^{+0.20}_{-0.18}\pm 0.07$)\%.Comment: 3 PS figures; corrected TeX file (April 21, 1995