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| 2. |
- Beko, G., et al.
(författare)
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The Indoor Chemical Human Emissions and Reactivity (ICHEAR) project: Overview of experimental methodology and preliminary results
- 2020
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Ingår i: Indoor Air. - : Hindawi Limited. - 1600-0668 .- 0905-6947. ; 30:6, s. 1213-1228
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Tidskriftsartikel (refereegranskat)abstract
- With the gradual reduction of emissions from building products, emissions from human occupants become more dominant indoors. The impact of human emissions on indoor air quality is inadequately understood. The aim of the Indoor Chemical Human Emissions and Reactivity (ICHEAR) project was to examine the impact on indoor air chemistry of whole-body, exhaled, and dermally emitted human bioeffluents under different conditions comprising human factors (t-shirts/shorts vs long-sleeve shirts/pants; age: teenagers, young adults, and seniors) and a variety of environmental factors (moderate vs high air temperature; low vs high relative humidity; presence vs absence of ozone). A series of human subject experiments were performed in a well-controlled stainless steel climate chamber. State-of-the-art measurement technologies were used to quantify the volatile organic compounds emitted by humans and their total OH reactivity; ammonia, nanoparticle, fluorescent biological aerosol particle (FBAP), and microbial emissions; and skin surface chemistry. This paper presents the design of the project, its methodologies, and preliminary results, comparing identical measurements performed with five groups, each composed of 4 volunteers (2 males and 2 females). The volunteers wore identical laundered new clothes and were asked to use the same set of fragrance-free personal care products. They occupied the ozone-free (<2 ppb) chamber for 3 hours (morning) and then left for a 10-min lunch break. Ozone (target concentration in occupied chamber ~35 ppb) was introduced 10 minutes after the volunteers returned to the chamber, and the measurements continued for another 2.5 hours. Under a given ozone condition, relatively small differences were observed in the steady-state concentrations of geranyl acetone, 6MHO, and 4OPA between the five groups. Larger variability was observed for acetone and isoprene. The absence or presence of ozone significantly influenced the steady-state concentrations of acetone, geranyl acetone, 6MHO, and 4OPA. Results of replicate experiments demonstrate the robustness of the experiments. Higher repeatability was achieved for dermally emitted compounds and their reaction products than for constituents of exhaled breath.
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| 4. |
- Cabovska, Blanka, 1990, et al.
(författare)
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Measured and perceived IEQ under different ventilation strategies in Swedish classrooms
- 2022
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Ingår i: 17th International Conference on Indoor Air Quality and Climate, INDOOR AIR 2022.
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Konferensbidrag (refereegranskat)abstract
- Indoor environmental quality was assessed in Swedish primary school classrooms grouped into three categories based on the ventilation system: 1) natural or exhaust ventilation, 2) balanced mechanical ventilation systems with constant air volume (CAV), 3) balanced mechanical ventilation systems with variable air volume (VAV). Measurements of NO2, ozone, TVOC, formaldehyde, PM10, and PM2.5 and a questionnaire survey were conducted. The concentrations of pollutants were integrated into Indoor Air Pollution Index allowing the rank comparison of classrooms. Children’s perception scores were calculated based on the questionnaire responses. Naturally ventilated classrooms had higher level of air pollution. No significant differences in pollutant levels were observed between classrooms with CAV and VAV systems. The type of ventilation system affected the subjective assessment of indoor air quality; it was worst in naturally ventilated classrooms.
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| 5. |
- Cabovska, Blanka, 1990, et al.
(författare)
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Ventilation strategies and indoor air quality in Swedish primary school classrooms
- 2022
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Ingår i: Building and Environment. - Göteborg : IVL Svenska Miljöinstitutet AB. - 0360-1323 .- 1873-684X. ; 226, s. 109744-109744
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Tidskriftsartikel (refereegranskat)abstract
- The present study aimed at investigating the effects of ventilation strategies on indoor air quality (IAQ) in schools. Measurements of thermal environment and IAQ were performed over 5 school days in 45 primary school classrooms in Gothenburg, Sweden, grouped into three categories according to their ventilation system: category A) natural or exhaust ventilation, or automated window opening; category B) balanced mechanical ventilationsystems with constant air volume (CAV) and category C) balanced mechanical ventilation systems with variable air volume (VAV). The classrooms performed equally well with respect to temperature and relative humidity regardless of the ventilation system. The concentrations of the air pollutants in all classrooms were generally below the respective guideline values. The concentrations of CO2, formaldehyde, PM10, and PM2.5 were lower in the B and C category classrooms with higher ventilation rates than in the A category classrooms. Indoor Air Pollution Index integrating concentrations of multiple pollutants was significantly higher the A category classrooms, reflecting poorer IAQ. Majority of the classrooms had lower ventilation rates than the Swedish ventilation requirements. The periodically reduced ventilation rates in the classrooms with VAV systems did not lead to substantial increase in the measured indoor pollutant concentrations.
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| 6. |
- Langer, Sarka, 1960, et al.
(författare)
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Squalene Depletion in Skin Following Human Exposure to Ozone under Controlled Chamber Conditions
- 2024
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Ingår i: Environmental Science & Technology. - 0013-936X .- 1520-5851. ; 58:15, s. 6693-6703
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Tidskriftsartikel (refereegranskat)abstract
- A major component of human skin oil is squalene, a highly unsaturated hydrocarbon that protects the skin from atmospheric oxidants. Skin oil, and thus squalene, is continuously replenished on the skin surface. Squalene is also quickly consumed through reactions with ozone and other oxidants. This study examined the extent of squalene depletion in the skin oils of the forearm of human volunteers after exposure to ozone in a climate chamber. Temperature, relative humidity (RH), skin coverage by clothing, and participants’ age were varied in a controlled manner. Concentrations of squalene were determined in skin wipe samples collected before and after ozone exposure. Exposures to ozone resulted in statistically significant decreases in post-exposure squalene concentrations compared to pre-exposure squalene concentrations in the skin wipes when squalene concentrations were normalized by concentrations of co-occurring cholesterol but not by co-occurring pyroglutamic acid (PGA). The rate of squalene loss due to ozonolysis was lower than its replenishment on the skin surface. Within the ranges examined, temperature and RH did not significantly affect the difference between normalized squalene levels in post-samples versus pre-samples. Although not statistically significant, skin coverage and age of the volunteers (three young adults, three seniors, and three teenagers) did appear to impact squalene depletion on the skin surfaces.
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| 7. |
- Langer, Sarka, 1960, et al.
(författare)
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Study of the measured and perceived indoor air quality in Swedish school classrooms
- 2020
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Ingår i: IOP Conference Series: Earth and Environmental Science. - : IOP Publishing. - 1755-1307 .- 1755-1315. ; 588:3
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Konferensbidrag (refereegranskat)abstract
- The influence of a classroom's indoor environment on children's health, performance and comfort is a concern that receives increasing attention. Many schools experience problems with inadequate indoor air quality and climate. Investigations of the indoor air quality (IAQ) in schools have been often non-systematic, which can lead to costly ad-hoc remediation actions. It is therefore important to develop a holistic approach to the assessment of IAQ in schools. This paper presents a field study on the indoor air quality and thermal environment conditions of elementary schools in Gothenburg, Sweden. The focus of the paper is on the methodology to investigate the IAQ using both objective measurements and subjective assessment of the perceived IAQ. The indoor environmental measurements include indoor air quality and thermal comfort parameters for which guideline values exist. Finally, a questionnaire was developed to evaluate the perception of the classroom's thermal environment and air quality by young children. The paper presents the study protocol and diagnostics approach for IAQ in classrooms. Examples of results from the first 10 investigated classrooms are presented.
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| 8. |
- 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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| 9. |
- 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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| 10. |
- Morawska, Lidia, et al.
(författare)
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Mandating indoor air quality for public buildings : if some countries lead by example, standards may increasingly become normalized
- 2024
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Ingår i: Science. - 0036-8075. ; 383:6690, s. 1418-1420
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Tidskriftsartikel (refereegranskat)abstract
- People living in urban and industrialized societies, which are expanding globally, spend more than 90% of their time in the indoor environment, breathing indoor air (IA). Despite decades of research and advocacy, most countries do not have legislated indoor air quality (IAQ) performance standards for public spaces that address concentration levels of IA pollutants. Few building codes address operation, maintenance, and retrofitting, and most do not focus on airborne disease transmission. But the COVID-19 pandemic has made all levels of society, from community members to decision-makers, realize the importance of IAQ for human health, wellbeing, productivity, and learning. We propose that IAQ standards be mandatory for public spaces. Although enforcement of IAQ performance standards in homes is not possible, homes must be designed and equipped so that they could meet the standards.For the past two decades, scientists have called for national IAQ standards and laws to be established (2), but so far, little action has been taken. The approach to IA contrasts sharply with outdoor air, for which quality is regulated and monitored and compliance with regulations is enforced. The World Health Organization (WHO) Global Air Quality Guidelines (AQG) published in 2021 provide recommendations for concentration levels of six pollutants and their averaging times (PM2.5, PM10, NO2, SO2, CO, and O3) and apply to both outdoor air and IA (3).In cases for which IAQ standard and guideline values were established by national or association working groups, the outcomes were inconsistent; often the criteria for the same parameter differed by orders of magnitude. The reasons cited for limited progress include different criteria in the selection of the critical study, in the starting point, and in the derivation procedure; the complex political, social, and legislative situation regarding IAQ; the lack of an open, systematic, and harmonized approach; and that establishing an IAQ standard is always the result of a compromise between scientific knowledge and political will. Because of the heterogenous landscape of approaches needed, such barriers remain intact despite the considerable IAQ research and evidence base developed over the past decades.
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