| 1. |
- Morawska, Lidia, et al.
(författare)
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COVID-19 and airborne transmission : science rejected, lives lost : can society do better?
- 2023
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Ingår i: Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. - : Oxford University Press (OUP). - 1537-6591. ; 76:10, s. 1854-1859
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Tidskriftsartikel (refereegranskat)abstract
- This is an account that should be heard of an important struggle: the struggle of a large group of experts who came together at the beginning of the Covid-19 pandemic to warn the world about the risk of airborne transmission and the consequences of ignoring it. We alerted the World Health Organization (WHO) about the potential significance of the airborne transmission of SARS-CoV-2 and the urgent need to control it, but our concerns were dismissed. Here we describe how this happened and the consequences. We hope that by reporting this story, we can raise awareness of the importance of interdisciplinary collaboration and the need to be open to new evidence, and to prevent it from happening again. Acknowledgement of an issue and the emergence of new evidence related to it, is the first necessary step towards finding effective mitigation solutions.
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| 2. |
- Morawska, Lidia, et al.
(författare)
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How can airborne transmission of COVID-19 indoors be minimised?
- 2020
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Ingår i: Environment International. - : Elsevier BV. - 1873-6750 .- 0160-4120. ; 142
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Tidskriftsartikel (refereegranskat)abstract
- During the rapid rise in COVID-19 illnesses and deaths globally, and notwithstanding recommended precautions, questions are voiced about routes of transmission for this pandemic disease. Inhaling small airborne droplets is probable as a third route of infection, in addition to more widely recognized transmission via larger respiratory droplets and direct contact with infected people or contaminated surfaces. While uncertainties remain regarding the relative contributions of the different transmission pathways, we argue that existing evidence is sufficiently strong to warrant engineering controls targeting airborne transmission as part of an overall strategy to limit infection risk indoors. Appropriate building engineering controls include sufficient and effective ventilation, possibly enhanced by particle filtration and air disinfection, avoiding air recirculation and avoiding overcrowding. Often, such measures can be easily implemented and without much cost, but if only they are recognised as significant in contributing to infection control goals. We believe that the use of engineering controls in public buildings, including hospitals, shops, offices, schools, kindergartens, libraries, restaurants, cruise ships, elevators, conference rooms or public transport, in parallel with effective application of other controls (including isolation and quarantine, social distancing and hand hygiene), would be an additional important measure globally to reduce the likelihood of transmission and thereby protect healthcare workers, patients and the general public.
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| 3. |
- Chen, Ailu, et al.
(författare)
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Indoor and outdoor particles in an air-conditioned building during and after the 2013 haze in Singapore
- 2016
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Ingår i: Building and Environment. - : Elsevier BV. - 0360-1323 .- 1873-684X. ; 99, s. 73-81
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Tidskriftsartikel (refereegranskat)abstract
- Particles released from biomass burning can contribute to severe air pollution. We monitored indoor and outdoor particles in a mechanically ventilated and air-conditioned building during and after the 2013 haze event in Singapore. Continuous monitoring of time-and size-resolved particles in the diameter range 0.01–10 μm was conducted for two weeks in each sampling campaign. During the haze event, the averaged size-resolved outdoor particle volume concentrations (dV/d(logDp)) for diameters larger than 0.3 μm were considerably higher than those during the post-haze days (9–185 μm3 cm−3versus 1–35 μm3 cm−3). However, the average number concentration of particles with diameters in the range 10–200 nm was substantially lower on the hazy days than on the post-haze days (11,400 to 14,300 particles cm−3 for hazy days, versus an average of 23,700 particles cm−3 on post-haze days). The building mechanical ventilation system, equipped with MERV 7 filters, attenuated the penetration and persistence of outdoor particles into the monitored building. Indoor particle concentrations, in the diameter ranges 0.3–1.0 μm and 1.0–2.5 μm, closely tracked the corresponding patterns of outdoor particle concentrations. For particles in the size range 0.01–1.0 μm, the size-resolved mean indoor/outdoor (I/O) ratios were in the range 0.12–0.65 with the highest mean I/O ratio at 0.3 μm (0.59 in AC on mode and 0.64 in AC off mode). The air conditioning and mechanical ventilation system with MERV 7 filters provided low single-pass removal efficiency (less than ∼ 30%) for particles with diameters of 0.01–1.0 μm. During the haze, for particles larger than ∼0.2 μm, lower I/O ratios and higher removal efficiencies occurred with the air conditioning operating as compared to with mechanical ventilation only. This observation suggests the possibility of particle loss to air conditioning system surfaces, possibly enhanced by thermophoretic or diffusiophoretic effects.
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| 4. |
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| 5. |
- Liu, Shichao, et al.
(författare)
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Predicted Percentage Dissatisfied with Ankle Draft
- 2017
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Ingår i: Indoor Air. - : Hindawi Limited. - 0905-6947 .- 1600-0668. ; 27:4, s. 852-862
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Tidskriftsartikel (refereegranskat)abstract
- Draft is unwanted local convective cooling. The draft risk model of Fanger et al. (Energy and Buildings 12, 21-39, 1988) estimates the percentage of people dissatisfied with air movement due to overcooling at the neck. There is no model for predicting draft at ankles, which is more relevant to stratified air distribution systems such as underfloor air distribution (UFAD) and displacement ventilation (DV). We developed a model for predicted percentage dissatisfied with ankle draft (PPDAD ) based on laboratory experiments with 110 college students. We assessed the effect on ankle draft of various combinations of air speed (nominal range: 0.1-0.6 m/s), temperature (nominal range: 16.5-22.5 °C), turbulence intensity (at ankles), sex, and clothing insulation (< 0.7 clo; lower legs uncovered and covered). The results show that whole body thermal sensation and air speed at ankles are the dominant parameters affecting draft. The seated subjects accepted a vertical temperature difference of up to 8 °C between ankles (0.1 m) and head (1.1 m) at neutral whole body thermal sensation, 5 °C more than the maximum difference recommended in existing standards. The developed ankle draft model can be implemented in thermal comfort and air diffuser testing standards.
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| 6. |
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| 7. |
- Schiavon, Stefano, et al.
(författare)
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Thermal comfort, perceived air quality and cognitive performance when personally controlled air movement is used by tropically acclimatized persons
- 2017
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Ingår i: Indoor Air. - : Hindawi Limited. - 0905-6947 .- 1600-0668. ; 27:3, s. 690-702
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Tidskriftsartikel (refereegranskat)abstract
- In a warm and humid climate, increasing the temperature set point offers considerable energy benefits with low first costs. Elevated air movement generated by a personally controlled fan can compensate for the negative effects caused by an increased temperature set point. Fifty-six tropically acclimatized persons in common Singaporean office attire (0.7 clo) were exposed for 90 minutes to each of five conditions: 23, 26, and 29°C and in the latter two cases with and without occupant-controlled air movement. Relative humidity was maintained at 60%. We tested thermal comfort, perceived air quality, sick building syndrome symptoms, and cognitive performance. We found that thermal comfort, perceived air quality, and sick building syndrome symptoms are equal or better at 26°C and 29°C than at the common set point of 23°C if a personally controlled fan is available for use. The best cognitive performance (as indicated by task speed) was obtained at 26°C; at 29°C, the availability of an occupant-controlled fan partially mitigated the negative effect of the elevated temperature. The typical Singaporean indoor air temperature set point of 23°C yielded the lowest cognitive performance. An elevated set point in air-conditioned buildings augmented with personally controlled fans might yield benefits for reduced energy use and improved indoor environmental quality in tropical climates.
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| 8. |
- Yang, Bin, et al.
(författare)
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Cooling efficiency of a brushless direct current stand fan
- 2015
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Ingår i: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 85, s. 196-204
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Tidskriftsartikel (refereegranskat)abstract
- The idea of far transfer effects in the cognitive sciences has received much attention in recent years. One domain where far transfer effects have frequently been reported is music education, with the prevailing idea that music practice entails an increase in cognitive ability (IQ). While cross-sectional studies consistently find significant associations between music practice and IQ, randomized controlled trials, however, report mixed results. An alternative to the hypothesis of cognitive transfer effects is that some underlying factors, such as shared genes, influence practice behaviour and IQ causing associations on the phenotypic level. Here we explored the hypothesis of far transfer within the framework of music practice. A co-twin control design combined with classical twin-modelling based on a sample of more than 10,500 twins was used to explore causal associations between music practice and IQ as well as underlying genetic and environmental influences. As expected, phenotypic associations were moderate (r = 0.11 and r = 0.10 for males and females, respectively). However, the relationship disappeared when controlling for genetic and shared environmental influences using the co-twin control method, indicating that a highly practiced twin did not have higher IQ than the untrained co-twin. In line with that finding, the relationship between practice and IQ was mostly due to shared genetic influences. Findings strongly suggest that associations between music practice and IQ in the general population are non-causal in nature. The implications of the present findings for research on plasticity, modularity, and transfer are discussed.
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| 9. |
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| 10. |
- Zhou, Jin, et al.
(författare)
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Particle Exposure during the 2013 Haze in Singapore : Importance of the Built Environment
- 2015
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Ingår i: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 93:1, s. 14-23
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Tidskriftsartikel (refereegranskat)abstract
- The 2013 haze was the most serious air pollution event in Singapore's history. Individual exposures to particulate matter differ (a) according to time patterns of behaviour and (b) with the varying degrees of protection provided by buildings against penetration and persistence of outdoor particles. Utilizing realtime personal monitoring, we evaluated exposures to size-segregated fine particulate matter (PM) of five office workers for six days during the latter portion of the 2013 haze event. The outdoor volume concentrations of particulate matter (0.3-2.5 mu m diameter) during moderate and light haze days were in the ranges 15-21 mu m(3)/cm(3) and 7-10 mu m(3)/cm(3), respectively. More than 80% of total daily exposures occurred indoors in workplaces and residences. The daily-integrated personal exposures for the five subjects during the moderate and light haze days were 140-454 (mu m(3)/cm(3))-h and 66-239 (mu m(3)/cm(3))-h, respectively. Exposure factors for the five participants, quantifying the extent of exposure reduction associated with being indoors, had daily average values ranging from 0.32 to 0.75. The results of this study contribute toward deeper understanding the degree of protection provided by the buildings from pollution of outdoor origin. The work also contributes knowledge regarding personal exposure to particulate matter during air pollution episodes, especially for tropical climates.
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