Exposure to Indoor PM2.5 and Perception of Air Quality and Productivity in an Office Building: An Intervention Study

Health impacts of exposure to particulate matter can be wide-ranging, with some evidence suggesting potential impacts on cognition and productivity. This study was conducted in an urban mixed-mode ventilated office in China. Sixty eligible employees agreed to participate in the study and fifty-five valid responses were obtained. The perception of air quality, productivity and wellbeing were assessed via questionnaires during three conditions: intervention, control, and baseline (a week prior to the intervention). Portable air purifiers on the subjects’ workstations were used as the intervention to control the PM2.5 level at subjects’ breathing zone. The air purifiers during the off and on status were considered as control and intervention conditions respectively. The same cohort was divided into four groups separately participating in each of three conditions on different workdays via a crossover design. The following PM2.5 levels [Average (SD)] during the three conditions (Baseline/Control/Intervention) were:[26.7 (2.1)/18.0 (1.8)/3.7 (0.9)] µg/m³.These levels correspond to interim targets of WHO guidelines for PM2.5. Analysis indicates significant differences between control and intervention regarding perception and satisfaction of air quality, thermal satisfaction and productivity

Impact of Indoor Temperature and CO2 Levels on Occupant Thermal Perception and Cognitive Performance of Adult Female Students in Saudi Arabia

Due to hot arid climate in Jeddah, Saudi Arabia, occupants rely on air conditioning (AC) to provide both ventilation requirements and thermal comfort. It is believed that this total reliance on AC have also a significant effect on thermal sensation as well as cognitive performance of building occupants. Using a multi-variable multilevel statistical analysis, the effects of classroom temperature and CO2 levels on cognitive performance were estimated. Eight neurobehavioral cognitive tests were used to evaluate cognitive performance of 499 female students (16-20 years old). In addition, thermal sensation votes were collected. All participants were exposed to nine different environmental conditions, a combination of three temperature levels 20°C, 23°C and 25°C, and three CO2 levels: 600 ppm, 1000 ppm and 1800 ppm. The baseline condition levels were set at 20°C and 600 ppm. In this paper the interrelationships between the thermal sensation votes and effects of classroom temperature and CO2 levels on vigilance (Simple Reaction Test, SRT) and memory tasks (Reversal Learning, RL) are presented. The results suggested that the ‘cold’ thermal sensations have been linked to significant increase in ‘percentage of errors’ for both memory and vigilance tasks. Also, the exposure to higher CO2 levels of 1800 ppm and 1000 ppm have led to a significant increase in the ‘percentage of errors’ for both cognitive performance tasks compared to the baseline conditions. The study has also confirmed that the significant influence of acclimatization should not be overlooked when setting up the environmental design criteria for buildings in hot arid climates

Moisture Performance Criteria for UK Dwellings

The new ventilation regulations in England and Wales have introduced performance criteria for the control of mould. The UK Government\'s Building Regulations Research Programme has funded University College London (UCL) to investigate the extent to which these are the most appropriate criteria for thecontrol of mould in UK dwellings. This paper reports on the plans for this study which involve both field and laboratory related work. Some initial early work has already been undertaken and the paper summarises the progress to date. This initial work is based on analysis of data from a national study of England\'s Home Energy Efficiency scheme (Warm Front). Surveys were undertaken of dwellings and households participating in the scheme in five urban areas. Half-hourly living room and main bedroom temperatures and relative humidity measurements were recorded for two to four weeks (in the heating season) in approximately 1600 dwellings. This data is being analysed to investigate the typical relativehumidities that exist in UK dwellings and also any relationship that exists between these levels and the mould growth that was recorded

Short-term exposure to indoor PM2.5 in office buildings and cognitive performance in adults: An intervention study

Impacts of exposure to particulate matter can be wide-ranging, with some evidence suggesting potential impacts on nervous system, cognition, and productivity. However, most evidence to date addresses ambient exposure and chronic outcomes with limited research on indoor short-term exposure to PM2.5 and cognitive performance. Hence, the aim of this study was to evaluate if there is a relationship between short-term exposure to indoor PM2.5 within the workplace context and cognitive performance in adults. A randomized single-blind cross-over trial was conducted in an urban mixed-mode ventilated office in Beijing (China). Sixty eligible employees participated in the study and fifty-five valid responses were obtained. Cognitive performance was assessed with a validated neurological battery test during intervention and control conditions. Portable air purifiers were placed on the subjects' workstations and used in the intervention condition to control PM2.5 levels at the subjects’ breathing zone whereas in the control condition, the air purifiers were present but switched off. Average PM2.5 levels were respectively 18.0 μg/m³ and 3.7 μg/m³ in the control and intervention condition. In each condition, cognitive performance testing started five to 7 h after arriving in the office. The results showed office workers had significantly better performance for 9 out of the 16 cognitive skills during the intervention, compared to the control condition, with the most consistent effect in the memory domain. This study adds evidence that elevated PM2.5 levels can detrimentally affect cognitive performance even during short-term indoor exposure. Further research is needed on the potential impact of other air pollutants, including ultrafine particles, and on the possible role of sound and air movement from the air purifiers

Dynamics of short-term and long-term decision-making in English housing associations: A study of using systems thinking to inform policy design

Incorporating consideration of causal mechanisms of complex policy issues and goals is critical for policy design, but tools to support exploration of the interconnections, trade-offs and unintended consequences of a focused policy issue are limited. Understanding how to undertake systems-based policy design is crucial for designing effective policy interventions. Through a case study with two housing associations (HAs) in England, this paper explores how group model building (GMB) workshops, as a systems thinking tool, can elicit complex causal mechanisms to inform policy design. The paper presents a causal loop diagram (CLD) describing English HAs’ decision-making around sustainable and healthy housing in response to housing policies. The CLD illustrates how frequent policy changes and disjointed objectives can create disruptive challenges for HA's long-term decision-making, increasing short-term decision-making, and compromising the delivery of housing policy goals as an unintended consequence. We argue that the systems perspective of the interlinkages between policy design, specifically inconsistencies and changes, and housing organisations’ reactions highlights the importance of the systems thinking approach of policy design to support HAs’ organisational decision-making for sustainability and social issues. Policy design elements that facilitate HAs’ long-term decision-making are discussed. Through the case study, we contribute to the housing policy literature by explicitly showing how policy changes affect HA's decision-making. We advance the integration of policy design and soft operational research fields by describing the systems thinking approaches are used not only on the content of policy design to enhance a particular policy, but also on increasing our understanding of its process, by generating insights about the nature of decision-making dynamics and challenges faced. Limitations and implications for future research are discussed

The Effects of Thermal Sensation and Acclimatisation on Cognitive Performance of Adult Female Students in Saudi Arabia Using Multivariable - Multilevel Statistical Modelling

In the hot climate of Saudi Arabia, people living year-round in air-conditioned spaces are likely to develop high expectations for homogeneity and cool temperatures, becoming potentially more sensitive if thermal conditions deviate from the comfort zone they expect. This paper presents the results from a field intervention investigating the association between participants’ thermal sensations with cognitive performance in a female university in Saudi Arabia. The climatic context plays a key role in choosing Saudi Arabia, whereas the total reliance on air-conditioners (AC) for cooling is believed to have significant effects on occupants’ perceptions of the comfort temperature. Results reveal discrepancies in the actual thermal sensations between the Saudi and non-Saudi participants which affected their performances. “Cool” and “Slightly Cool” sensations versus neutral were associated with significant lower percentage of errors and significant higher speed for all participants independently of any association with ethnicity and acclimatization. The estimates remained significant even after adjusting for ethnicity and the number of years spent in the country and the set temperature of AC at home. Implications of the study suggest a preference for staying cool when working independently of acclimatization status

Combined effects of ventilation rates and indoor temperatures on cognitive performance of female higher education students in a hot climate

Impairment in mental functions attributed to the effects of indoor air quality and thermal conditions has received considerable attention in the past decade, particularly for educational buildings where students’ cognitive performance is essential to foster learning. This study explores the combined effects of indoor temperatures and CO2 levels as markers for ventilation rates on cognitive performance among female students (16– 23 years old) in Saudi Arabia. The longitudinal experiments involved nine conditions combining three CO2 concentration levels (achieved via changes in ventilation) and three temperature levels involving 499 participants, all exposed to the nine conditions. The study implemented a computer- based cognitive performance battery with “9Button” keyboards. Univariable and multivariable multilevel regression models explored the association of indoor temperature and CO2 levels (as markers for ventilation rates) with cognitive performance after adjusting for potential confound-ers. Potential benefits were found on speed and accuracy of tasks of cognitive perfor-mance when indoor temperature was set between 20 and 23ºC and at CO2 levels of 600 ppm compared to higher temperatures and poorer ventilation rates and that both ventilation and thermal environmental control are important and need to be improved for achieving optimum learning conditions. Nevertheless, the results are relevant for short-term exposures lasting no more than 2 h