This page has only limited features, please log in for full access.
Humans emit carbon dioxide (CO2) as a product of their metabolism. Its concentration in buildings is used as a marker of ventilation rate (VR) and degree of mixing of supply air, and indoor air quality (IAQ). The CO2 emission rate (CER) may be used to estimate the ventilation rate. Many studies have measured CERs from subjects who were awake but little data are available from sleeping subjects and the present publication was intended to reduce this gap in knowledge. Seven females (29 ± 5 years old; BMI: 22.2 ± 0.8 kg/m2) and four males (27 ± 1 years old; BMI: 20.5 ± 1.5 kg/m2) slept for four consecutive nights in a specially constructed capsule at two temperatures (24 and 28°C) and two VRs that maintained CO2 levels at ca. 800 ppm and 1700 ppm simulating sleeping conditions reported in the literature. The order of exposure was balanced, and the first night was for adaptation. Their physiological responses, including heart rate, pNN50, core body temperature, and skin temperature, were measured as well as sleep quality, and subjective responses were collected each evening and morning. Measured steady-state CO2 concentrations during sleep were used to estimate CERs with a mass-balance equation. The average CER was 11.0 ± 1.4 L/h per person and was 8% higher for males than for females (P < 0.05). Increasing the temperature or decreasing IAQ by decreasing VR had no effects on measured CERs and caused no observable differences in physiological responses. We also calculated CERs for sleeping subjects using the published data on sleep energy expenditure (SEE) and Respiratory Quotient (RQ), and our measured CERs confirmed both these calculations and the CERs predicted using the equations provided by ASHRAE Standard 62.1, ASHRAE Handbook, and ASTM D6245-18. The present results provide a valuable and helpful reference for the design and control of bedroom ventilation but require confirmation and extension to other age groups and populations.
Xiaojun Fan; Mitsuharu Sakamoto; Huiqi Shao; Kazuki Kuga; Kazuhide Ito; Li Lan; Pawel Wargocki. Emission rate of carbon dioxide while sleeping. Indoor Air 2021, 1 .
AMA StyleXiaojun Fan, Mitsuharu Sakamoto, Huiqi Shao, Kazuki Kuga, Kazuhide Ito, Li Lan, Pawel Wargocki. Emission rate of carbon dioxide while sleeping. Indoor Air. 2021; ():1.
Chicago/Turabian StyleXiaojun Fan; Mitsuharu Sakamoto; Huiqi Shao; Kazuki Kuga; Kazuhide Ito; Li Lan; Pawel Wargocki. 2021. "Emission rate of carbon dioxide while sleeping." Indoor Air , no. : 1.
This study managed to create thermal comfort conditions at three temperatures (24°C-T24, 26°C-T26, and 28°C-T28) by adjusting clothing and air velocity. Thirty-six subjects (18 males and 18 females) were exposed to each of the three conditions for 4.5 h in a design balanced for order of presentation of conditions. During each exposure, they rated the physical environment, their comfort, the intensity of acute subclinical health symptoms, and their mental load, and they performed a number of cognitive tasks. Their physiological reactions were monitored. The subjects rated T24 to be comfortably cool, T26 to be comfortably neutral, and T28 to be comfortably warm. Their self-estimated performance did not differ between conditions but 12 of 14 objective metrics of cognitive performance decreased significantly at the elevated temperatures: compared with T24, their average cognitive performance decreased by 10% at T26 and by 6% at T28. At the elevated temperatures, their parasympathetic nervous system activity (as indicated by PNN50) and their arterial blood oxygen saturation level (SpO2) were both lower, which would be expected to result in reduced cognitive performance. The subjects also rated their acute subclinical health symptoms as more intense and their workload as higher at the elevated temperatures. These results suggest that where cognitive performance is the priority, it is wise to ensure a comfortably cool environment. The present study also supports the use of fans or natural ventilation to reduce the need for mechanical cooling.
Li Lan; Jieyu Tang; Pawel Wargocki; David P Wyon; Zhiwei Lian. Cognitive performance was reduced by higher air temperature even when thermal comfort was maintained over the 24–28°C range. Indoor Air 2021, 1 .
AMA StyleLi Lan, Jieyu Tang, Pawel Wargocki, David P Wyon, Zhiwei Lian. Cognitive performance was reduced by higher air temperature even when thermal comfort was maintained over the 24–28°C range. Indoor Air. 2021; ():1.
Chicago/Turabian StyleLi Lan; Jieyu Tang; Pawel Wargocki; David P Wyon; Zhiwei Lian. 2021. "Cognitive performance was reduced by higher air temperature even when thermal comfort was maintained over the 24–28°C range." Indoor Air , no. : 1.
Three conditions were established to investigate the effects of ventilation and related ventilation noise on sleep quality: No mechanical ventilation/low noise (A); Mechanical ventilation /low noise (B); Mechanical ventilation/high noise (C). The interventions were achieved by idling a mechanical ventilation system or operating it in two different modes. Nine young people and nine older people were all exposed to each of the three conditions for a whole night's sleep, but data from only 15 subjects were analyzed as three young subjects apparently slept with open windows in condition A. Sleep quality was measured objectively with polysomnography (PSG), which monitored signals of electroencephalogram (EEG), bilateral electrooculogram (EOG), and chin electromyogram (EMG) continuously during the sleeping period. Saliva samples were collected before sleep at night and after waking in the morning, and the concentrations of cortisol and lysozyme in them were determined. Without mechanical ventilation, the indoor CO2 level averaged about 1400 ppm during the night. Operating the mechanical ventilation decreased the indoor CO2 to below 1000 ppm, which improved objectively measured sleep quality: wake time after sleep onset (WASO) decreased on average by 15 min (p < 0.05) and sleep efficiency (SE) increased on average by about 4% (p < 0.05). Increased ventilation noise level (50.8dB(A) vs. 34.7dB(A); 54.9dB(C) vs. 48dB(C)) did not significantly change SE or WASO but did change the duration of sleep stages: It decreased the duration of deep sleep by 11min (p < 0.05) and REM sleep by 17 min (p < 0.01) and increased the duration of light sleep by 17 min (p < 0.05). The ventilation noise significantly increased the concentration of lysozyme in the elderly (p < 0.05) although no significant effects on cortisol could be shown. These results confirm that a low ventilation rate has negative effects on sleep quality and that ventilation noise at or above 50dB(A) may disrupt sleep.
Li Lan; Yuxiang Sun; David P. Wyon; Pawel Wargocki. Pilot study of the effects of ventilation and ventilation noise on sleep quality in the young and elderly. Indoor Air 2021, 1 .
AMA StyleLi Lan, Yuxiang Sun, David P. Wyon, Pawel Wargocki. Pilot study of the effects of ventilation and ventilation noise on sleep quality in the young and elderly. Indoor Air. 2021; ():1.
Chicago/Turabian StyleLi Lan; Yuxiang Sun; David P. Wyon; Pawel Wargocki. 2021. "Pilot study of the effects of ventilation and ventilation noise on sleep quality in the young and elderly." Indoor Air , no. : 1.
Chandra Sekhar; Mizuho Akimoto; Xiaojun Fan; Mariya Bivolarova; Chenxi Liao; Li Lan; Pawel Wargocki. Corrigendum to “Bedroom ventilation: Review of existing evidence and current standards” [J. Build. Environ. 184 (2020) 107229]. Building and Environment 2021, 201, 107983 .
AMA StyleChandra Sekhar, Mizuho Akimoto, Xiaojun Fan, Mariya Bivolarova, Chenxi Liao, Li Lan, Pawel Wargocki. Corrigendum to “Bedroom ventilation: Review of existing evidence and current standards” [J. Build. Environ. 184 (2020) 107229]. Building and Environment. 2021; 201 ():107983.
Chicago/Turabian StyleChandra Sekhar; Mizuho Akimoto; Xiaojun Fan; Mariya Bivolarova; Chenxi Liao; Li Lan; Pawel Wargocki. 2021. "Corrigendum to “Bedroom ventilation: Review of existing evidence and current standards” [J. Build. Environ. 184 (2020) 107229]." Building and Environment 201, no. : 107983.
The effects of two window states (closed or open) on the bedroom environment and on sleep quality were investigated. Twenty-seven subjects (14 males and 13 females, 20-33 years old) without sleep disorders and chronic diseases participated. The subjects slept for two consecutive nights with windows open and two consecutive nights with windows closed in four dormitory rooms adapted for the purpose of this study, one person at a time. The order of exposure was balanced among participants. Bed temperature, room temperature, relative humidity (RH), carbon dioxide (CO2), particles (PM2.5), and noise were monitored during sleep. Sleep quality was measured using subjective ratings, a wrist-worn sleep tracker, and (for one group of 14 subjects only) polysomnography (PSG) for home use; snoring in this sub-group and awakenings were also registered. Higher PM2.5 and noise levels were found with windows open, while higher room temperature, RH, and CO2 levels were measured with windows closed. There were no differences between conditions in terms of objectively measured sleep stages but the subjects with the PSG attached snored significantly less and woke up significantly less often when sleeping with windows open. Start sleep time, end sleep time, total sleep time (TST) and time in bed (TIB) measured with the sleep tracker were confirmed by the measurements made using PSG, light sleep (N1 + N2) and sleep latency were in moderate agreement but there was no significant agreement for REM and deep sleep (N3). When sleeping with windows open, the subjects rated the air as fresher but reported higher noise levels, feeling less rested, a worse mental state and well-being, and their replies on the Groningen sleep quality scale indicated poorer sleep quality. There was no clear association between the performance test score and sleep quality. These results suggest that sleeping with windows open can provide some benefits by increasing ventilation with outdoor air, reducing CO2 concentrations, improving air quality as indicated by the subjectively rated air freshness and some of the parameters defining sleep quality, but it may also result in some discomfort if there are episodic loud noise events outdoors. Further studies are required to clarify the role of open windows in achieving good sleep quality.
Chenxi Liao; Marc Delghust; Pawel Wargocki; Jelle Laverge. Effects of window opening on the bedroom environment and resulting sleep quality. Science and Technology for the Built Environment 2021, 1 -21.
AMA StyleChenxi Liao, Marc Delghust, Pawel Wargocki, Jelle Laverge. Effects of window opening on the bedroom environment and resulting sleep quality. Science and Technology for the Built Environment. 2021; ():1-21.
Chicago/Turabian StyleChenxi Liao; Marc Delghust; Pawel Wargocki; Jelle Laverge. 2021. "Effects of window opening on the bedroom environment and resulting sleep quality." Science and Technology for the Built Environment , no. : 1-21.
In a business as usual scenario, atmospheric carbon dioxide concentration (CO2) could reach 950 parts per million (ppm) by 2100. Indoor CO2 concentrations will rise consequently, given its dependence on atmospheric CO2 levels. If buildings are ventilated following current standards in 2100, indoor CO2 concentration could be over 1300 ppm, depending on specific ventilation codes. Such exposure to CO2 could have physiological and psychological effects on building occupants. We conducted a randomized, within‐subject study, examining the physiological effects on the respiratory functions of 15 persons. We examined three exposures, each 150 min long, with CO2 of: 900 ppm (reference), 1450 ppm (decreased ventilation), and 1450 ppm (reference condition with added pure CO2). We measured respiratory parameters with capnometry and forced vital capacity (FVC) tests. End‐tidal CO2 and respiration rates did not significantly differ across the three exposures. Parameters measured using FVC decreased significantly from the start to the end of exposure only at the reduced ventilation condition (p < 0.04, large effect size). Hence, poor ventilation likely affects respiratory parameters. This effect is probably not caused by increased CO2 alone and rather by other pollutants—predominantly human bioeffluents in this work—whose concentrations increased as a result.
Asit Kumar Mishra; Stefano Schiavon; Pawel Wargocki; Kwok Wai Tham. Respiratory performance of humans exposed to moderate levels of carbon dioxide. Indoor Air 2021, 31, 1540 -1552.
AMA StyleAsit Kumar Mishra, Stefano Schiavon, Pawel Wargocki, Kwok Wai Tham. Respiratory performance of humans exposed to moderate levels of carbon dioxide. Indoor Air. 2021; 31 (5):1540-1552.
Chicago/Turabian StyleAsit Kumar Mishra; Stefano Schiavon; Pawel Wargocki; Kwok Wai Tham. 2021. "Respiratory performance of humans exposed to moderate levels of carbon dioxide." Indoor Air 31, no. 5: 1540-1552.
The emission rate of carbon dioxide (CO2) depends on many factors but mainly on the activity level (metabolic rate) of occupants. In this study, we examined two other factors that may influence the CO2 emission rate, namely the background CO2 concentration and the indoor temperature. Six male volunteers sat one by one in a 1.7 m3 chamber for 2.5 h and performed light office‐type work under five different conditions with two temperature levels (23 vs. 28°C) and three background concentrations of CO2 (800 vs. 1400 vs. 3000 ppm). Background CO2 levels were increased either by dosing CO2 from a cylinder or by reducing the outdoor air supply rate. Physiological responses to warmth, added CO2, and bioeffluents were monitored. The rate of CO2 emission was estimated using a mass‐balance equation. The results indicate a higher CO2 emission rate at the higher temperature, at which the subjects were warm, and a lower emission rate in all conditions in which the background CO2 concentration increased. Physiological measurements partially explained the present results but more measurements are needed.
Kazuki Kuga; Kazuhide Ito; Pawel Wargocki. The effects of warmth and CO 2 concentration, with and without bioeffluents, on the emission of CO 2 by occupants and physiological responses. Indoor Air 2021, 1 .
AMA StyleKazuki Kuga, Kazuhide Ito, Pawel Wargocki. The effects of warmth and CO 2 concentration, with and without bioeffluents, on the emission of CO 2 by occupants and physiological responses. Indoor Air. 2021; ():1.
Chicago/Turabian StyleKazuki Kuga; Kazuhide Ito; Pawel Wargocki. 2021. "The effects of warmth and CO 2 concentration, with and without bioeffluents, on the emission of CO 2 by occupants and physiological responses." Indoor Air , no. : 1.
We reviewed 47 documents published 1967–2019 that reported measurements of volatile organic compounds (VOCs) on commercial aircraft. We compared the measurements with the air quality standards and guidelines for aircraft cabins and in some cases buildings. Average levels of VOCs for which limits exist were lower than the permissible levels except for benzene with average concentration at 5.9 ± 5.5 μg/m3. Toluene, benzene, ethylbenzene, formaldehyde, acetaldehyde, limonene, nonanal, hexanal, decanal, octanal, acetic acid, acetone, ethanol, butanal, acrolein, isoprene and menthol were the most frequently measured compounds. The concentrations of semi‐volatile organic compounds (SVOCs) and other contaminants did not exceed standards and guidelines in buildings except for the average NO2 concentration at 12 ppb. Although the focus was on VOCs, we also retrieved the data on other parameters characterizing cabin environment. Ozone concentration averaged 38 ppb below the upper limit recommended for aircraft. The outdoor air supply rate ranged from 1.7 to 39.5 L/s per person and averaged 6.0 ± 0.8 L/s/p (median 5.8 L/s/p), higher than the minimum level recommended for commercial aircraft. Carbon dioxide concentration averaged 1315 ± 232 ppm, lower than what is permitted in aircraft and close to what is permitted in buildings. Measured temperatures averaged 23.5 ± 0.8°C and were generally within the ranges recommended for avoiding thermal discomfort. Relative humidity averaged 16% ± 5%, lower than what is recommended in buildings.
Ruiqing Chen; Lei Fang; Junjie Liu; Britta Herbig; Victor Norrefeldt; Florian Mayer; Richard Fox; Pawel Wargocki. Cabin air quality on non‐smoking commercial flights: A review of published data on airborne pollutants. Indoor Air 2021, 31, 926 -957.
AMA StyleRuiqing Chen, Lei Fang, Junjie Liu, Britta Herbig, Victor Norrefeldt, Florian Mayer, Richard Fox, Pawel Wargocki. Cabin air quality on non‐smoking commercial flights: A review of published data on airborne pollutants. Indoor Air. 2021; 31 (4):926-957.
Chicago/Turabian StyleRuiqing Chen; Lei Fang; Junjie Liu; Britta Herbig; Victor Norrefeldt; Florian Mayer; Richard Fox; Pawel Wargocki. 2021. "Cabin air quality on non‐smoking commercial flights: A review of published data on airborne pollutants." Indoor Air 31, no. 4: 926-957.
Jan Sundell; John Spengler; Pawel Wargocki. VENTILATION: WHY does no one take it seriously? Indoor Air 2021, 31, 605 -607.
AMA StyleJan Sundell, John Spengler, Pawel Wargocki. VENTILATION: WHY does no one take it seriously? Indoor Air. 2021; 31 (3):605-607.
Chicago/Turabian StyleJan Sundell; John Spengler; Pawel Wargocki. 2021. "VENTILATION: WHY does no one take it seriously?" Indoor Air 31, no. 3: 605-607.
To avoid health risks and discomfort, the European Energy Performance for Building Directive (EPBD) mandates that “Member States should support energy performance upgrades of existing buildings that contribute to achieving a healthy indoor environment.” There is, however, no widely accepted method for rating the overall level of indoor environmental quality (IEQ), although several different approaches are proposed by standards, guidelines, and certification schemes. To fill this void, a new classification rating scheme called TAIL was developed to rate IEQ in offices and hotels undergoing deep energy renovation during their normal use; the scheme is a part of the energy certification method developed by the EU ALDREN project. The TAIL scheme standardizes rating of the quality of the thermal (T) environment, acoustic (A) environment, indoor air (I), and luminous (L) environment, and by using these ratings, it provides a rating of the overall level of IEQ. Twelve parameters are rated by measurements, modelling, and observation to provide the input to the overall rating of IEQ. Their quality levels are determined primarily using Standard EN-16798-1 and World Health Organization (WHO) air quality guidelines and are expressed by colours and Roman numerals to improve communication. The TAIL rating was shown to discriminate IEQ levels when its feasibility was examined in eleven buildings across Europe to provide support for its applicability and input for further modifications. Opportunities for using the scheme in other types of buildings and for its further development and application are discussed.
Pawel Wargocki; Wenjuan Wei; Jana Bendžalová; Carlos Espigares-Correa; Christophe Gerard; Olivier Greslou; Mathieu Rivallain; Marta Maria Sesana; Bjarne W. Olesen; Johann Zirngibl; Corinne Mandin. TAIL, a new scheme for rating indoor environmental quality in offices and hotels undergoing deep energy renovation (EU ALDREN project). Energy and Buildings 2021, 244, 111029 .
AMA StylePawel Wargocki, Wenjuan Wei, Jana Bendžalová, Carlos Espigares-Correa, Christophe Gerard, Olivier Greslou, Mathieu Rivallain, Marta Maria Sesana, Bjarne W. Olesen, Johann Zirngibl, Corinne Mandin. TAIL, a new scheme for rating indoor environmental quality in offices and hotels undergoing deep energy renovation (EU ALDREN project). Energy and Buildings. 2021; 244 ():111029.
Chicago/Turabian StylePawel Wargocki; Wenjuan Wei; Jana Bendžalová; Carlos Espigares-Correa; Christophe Gerard; Olivier Greslou; Mathieu Rivallain; Marta Maria Sesana; Bjarne W. Olesen; Johann Zirngibl; Corinne Mandin. 2021. "TAIL, a new scheme for rating indoor environmental quality in offices and hotels undergoing deep energy renovation (EU ALDREN project)." Energy and Buildings 244, no. : 111029.
In the CleanSky 2 ComAir study, subject tests were conducted in the Fraunhofer Flight Test Facility cabin mock-up. This mock-up consists of the front section of a former in-service A310 hosting up to 80 passengers. In 12 sessions the outdoor/recirculation airflow ratio was altered from today’s typically applied fractions to up to 88% recirculation fraction. This leads to increased relative humidity, carbon dioxide (CO2) and Total Volatile Organic Compounds (TVOC) levels in the cabin air, as the emissions by passengers become less diluted by outdoor, dry air. This paper describes the measured increase of relative humidity, CO2 and TVOC level in the cabin air for the different test conditions.
Victor Norrefeldt; Florian Mayer; Britta Herbig; Ria Ströhlein; Pawel Wargocki; Fang Lei. Effect of Increased Cabin Recirculation Airflow Fraction on Relative Humidity, CO2 and TVOC. Aerospace 2021, 8, 15 .
AMA StyleVictor Norrefeldt, Florian Mayer, Britta Herbig, Ria Ströhlein, Pawel Wargocki, Fang Lei. Effect of Increased Cabin Recirculation Airflow Fraction on Relative Humidity, CO2 and TVOC. Aerospace. 2021; 8 (1):15.
Chicago/Turabian StyleVictor Norrefeldt; Florian Mayer; Britta Herbig; Ria Ströhlein; Pawel Wargocki; Fang Lei. 2021. "Effect of Increased Cabin Recirculation Airflow Fraction on Relative Humidity, CO2 and TVOC." Aerospace 8, no. 1: 15.
Many people spend most of their time in an indoor environment. A positive relationship exists between indoor environmental quality and the health, wellbeing, and productivity of occupants in buildings. The indoor environment is affected by pollutants, such as gases and particles. Pollutants can be removed from the indoor environment in various ways. Air-cleaning devices are commonly marketed as benefiting the removal of air pollutants and, consequently, improving indoor air quality. Depending on the type of cleaning technology, air cleaners may generate undesired and toxic byproducts. Different air filtration technologies, such as electrostatic precipitators (ESPs) have been introduced to the market. The ESP has been used in buildings because it can remove particles while only causing low pressure drops. Moreover, ESPs can be either in-duct or standalone units. This review aims to provide an overview of ESP use, methods for testing this product, the performance of existing ESPs concerning removing pollutants and their byproducts, and the existing market for ESPs.
Alireza Afshari; Lars Ekberg; Luboš Forejt; Jinhan Mo; Siamak Rahimi; Jeffrey Siegel; Wenhao Chen; Pawel Wargocki; Sultan Zurami; Jianshun Zhang. Electrostatic Precipitators as an Indoor Air Cleaner—A Literature Review. Sustainability 2020, 12, 8774 .
AMA StyleAlireza Afshari, Lars Ekberg, Luboš Forejt, Jinhan Mo, Siamak Rahimi, Jeffrey Siegel, Wenhao Chen, Pawel Wargocki, Sultan Zurami, Jianshun Zhang. Electrostatic Precipitators as an Indoor Air Cleaner—A Literature Review. Sustainability. 2020; 12 (21):8774.
Chicago/Turabian StyleAlireza Afshari; Lars Ekberg; Luboš Forejt; Jinhan Mo; Siamak Rahimi; Jeffrey Siegel; Wenhao Chen; Pawel Wargocki; Sultan Zurami; Jianshun Zhang. 2020. "Electrostatic Precipitators as an Indoor Air Cleaner—A Literature Review." Sustainability 12, no. 21: 8774.
Sleep is essential for our health and well-being. Some research suggests that air quality influences sleep quality in bedrooms, but the evidence is limited. Research, until now, has focused on how indoor air quality affects health, comfort, and cognitive performance during waking hours. Less information is available on the levels of indoor air quality and ventilation in bedrooms, as well as on their consequences for sleep quality and the next-day performance. This paper addresses the former by reviewing research published in peer-reviewed journals in this millennium. The bedroom ventilation has been chosen as a specific focus of this review paper, which also includes a review of selected international standards for bedroom ventilation. Arising out of this review based on a framework of comparison of field data with CO2 and ventilation benchmarks from widely adopted international standards, an attempt is made to generalize the level of bedroom ventilation that exists in practice in residential dwellings and apartments across different seasons and different parts of the world. Besides, based on a limited number of studies dealing with the impact of bedroom ventilation on sleep quality, an attempt is also made to associate the measured field data with a potential impact on sleep quality.
Chandra Sekhar; Mizuho Akimoto; Xiaojun Fan; Mariya Bivolarova; Chenxi Liao; Li Lan; Pawel Wargocki. Bedroom ventilation: Review of existing evidence and current standards. Building and Environment 2020, 184, 107229 .
AMA StyleChandra Sekhar, Mizuho Akimoto, Xiaojun Fan, Mariya Bivolarova, Chenxi Liao, Li Lan, Pawel Wargocki. Bedroom ventilation: Review of existing evidence and current standards. Building and Environment. 2020; 184 ():107229.
Chicago/Turabian StyleChandra Sekhar; Mizuho Akimoto; Xiaojun Fan; Mariya Bivolarova; Chenxi Liao; Li Lan; Pawel Wargocki. 2020. "Bedroom ventilation: Review of existing evidence and current standards." Building and Environment 184, no. : 107229.
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.
Lidia Morawska; Julian W. Tang; William Bahnfleth; Philomena M. Bluyssen; Atze Boerstra; Giorgio Buonanno; Junji Cao; Stephanie Dancer; Andres Floto; Francesco Franchimon; Charles Haworth; Jaap Hogeling; Christina Isaxon; Jose L Jimenez; Jarek Kurnitski; Yuguo Li; Marcel Loomans; Guy Marks; Linsey C. Marr; Livio Mazzarella; Arsen Krikor Melikov; Shelly Miller; Donald K. Milton; William Nazaroff; Peter V. Nielsen; Catherine Noakes; Jordan Peccia; Xavier Querol; Chandra Sekhar; Olli Seppänen; Shin-Ichi Tanabe; Raymond Tellier; Kwok Wai Tham; Pawel Wargocki; Aneta Wierzbicka; Maosheng Yao. How can airborne transmission of COVID-19 indoors be minimised? Environment International 2020, 142, 105832 -105832.
AMA StyleLidia Morawska, Julian W. Tang, William Bahnfleth, Philomena M. Bluyssen, Atze Boerstra, Giorgio Buonanno, Junji Cao, Stephanie Dancer, Andres Floto, Francesco Franchimon, Charles Haworth, Jaap Hogeling, Christina Isaxon, Jose L Jimenez, Jarek Kurnitski, Yuguo Li, Marcel Loomans, Guy Marks, Linsey C. Marr, Livio Mazzarella, Arsen Krikor Melikov, Shelly Miller, Donald K. Milton, William Nazaroff, Peter V. Nielsen, Catherine Noakes, Jordan Peccia, Xavier Querol, Chandra Sekhar, Olli Seppänen, Shin-Ichi Tanabe, Raymond Tellier, Kwok Wai Tham, Pawel Wargocki, Aneta Wierzbicka, Maosheng Yao. How can airborne transmission of COVID-19 indoors be minimised? Environment International. 2020; 142 ():105832-105832.
Chicago/Turabian StyleLidia Morawska; Julian W. Tang; William Bahnfleth; Philomena M. Bluyssen; Atze Boerstra; Giorgio Buonanno; Junji Cao; Stephanie Dancer; Andres Floto; Francesco Franchimon; Charles Haworth; Jaap Hogeling; Christina Isaxon; Jose L Jimenez; Jarek Kurnitski; Yuguo Li; Marcel Loomans; Guy Marks; Linsey C. Marr; Livio Mazzarella; Arsen Krikor Melikov; Shelly Miller; Donald K. Milton; William Nazaroff; Peter V. Nielsen; Catherine Noakes; Jordan Peccia; Xavier Querol; Chandra Sekhar; Olli Seppänen; Shin-Ichi Tanabe; Raymond Tellier; Kwok Wai Tham; Pawel Wargocki; Aneta Wierzbicka; Maosheng Yao. 2020. "How can airborne transmission of COVID-19 indoors be minimised?" Environment International 142, no. : 105832-105832.
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, 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.
Gabriel Bekö; Pawel Wargocki; Nijing Wang; Mengze Li; Charles J. Weschler; Glenn Morrison; Sarka Langer; Lisa Ernle; Dusan Licina; Shen Yang; Nora Zannoni; Jonathan Williams. The Indoor Chemical Human Emissions and Reactivity (ICHEAR) project: Overview of experimental methodology and preliminary results. Indoor Air 2020, 30, 1213 -1228.
AMA StyleGabriel Bekö, Pawel Wargocki, Nijing Wang, Mengze Li, Charles J. Weschler, Glenn Morrison, Sarka Langer, Lisa Ernle, Dusan Licina, Shen Yang, Nora Zannoni, Jonathan Williams. The Indoor Chemical Human Emissions and Reactivity (ICHEAR) project: Overview of experimental methodology and preliminary results. Indoor Air. 2020; 30 (6):1213-1228.
Chicago/Turabian StyleGabriel Bekö; Pawel Wargocki; Nijing Wang; Mengze Li; Charles J. Weschler; Glenn Morrison; Sarka Langer; Lisa Ernle; Dusan Licina; Shen Yang; Nora Zannoni; Jonathan Williams. 2020. "The Indoor Chemical Human Emissions and Reactivity (ICHEAR) project: Overview of experimental methodology and preliminary results." Indoor Air 30, no. 6: 1213-1228.
Well-being in the built environment is a topic that features frequently in building standards and certification schemes, in scholarly articles and in the general press. However, despite this surge in attention, there are still many questions on how to effectively design, measure, and nurture well-being in the built environment. Bringing together experts from academia and the building industry, this paper aims to demonstrate that the promotion of well-being requires a departure from conventional agendas. The ten questions and answers have been arranged to offer a range of perspectives on the principles and strategies that can better sustain the consideration of well-being in the design and operation of the built environment. Placing a specific focus on some of the key physical factors (e.g., light, temperature, sound, and air quality) of indoor environmental quality (IEQ) that strongly influence occupant perception of built spaces, attention is also given to the value of multi-sensory variability, to how to monitor and communicate well-being outcomes in support of organizational and operational strategies, and to future research needs and their translation into building practice and standards. Seen as a whole, a new framework emerges, accentuating the integration of diverse new competencies required to support the design and operation of built environments that respond to the multifaceted physical, physiological, and psychological needs of their occupants.
Sergio Altomonte; Joseph Allen; Philomena M. Bluyssen; Gail Brager; Lisa Heschong; Angela Loder; Stefano Schiavon; Jennifer A. Veitch; Lily Wang; Pawel Wargocki. Ten questions concerning well-being in the built environment. Building and Environment 2020, 180, 106949 .
AMA StyleSergio Altomonte, Joseph Allen, Philomena M. Bluyssen, Gail Brager, Lisa Heschong, Angela Loder, Stefano Schiavon, Jennifer A. Veitch, Lily Wang, Pawel Wargocki. Ten questions concerning well-being in the built environment. Building and Environment. 2020; 180 ():106949.
Chicago/Turabian StyleSergio Altomonte; Joseph Allen; Philomena M. Bluyssen; Gail Brager; Lisa Heschong; Angela Loder; Stefano Schiavon; Jennifer A. Veitch; Lily Wang; Pawel Wargocki. 2020. "Ten questions concerning well-being in the built environment." Building and Environment 180, no. : 106949.
This study investigated whether adjusting clothing to remain in neutral thermal comfort at moderately elevated temperature is capable of avoiding negative effects on perceived acute subclinical health symptoms, comfort and cognitive performance. Two temperatures were examined: 23°C and 27°C. Twelve subjects were able to remain thermally comfortable at both temperatures by adjusting their clothing. They rated the physical environment, their comfort, the intensity of acute subclinical health symptoms and their mental load and they performed a number of cognitive tasks. Their physiological reactions were monitored. Their performance of several tasks was significantly worse at 27°C and they reported increased mental load at this temperature. Skin temperature and humidity and respiration rate were higher while blood oxygen saturation (SpO2) and pNN50 were lower at this temperature, the latter indicating increased stress. It is inferred that the observed physiological responses were mainly responsible for the negative effects on performance, as the subjects did not indicate any increased intensity of acute subclinical health symptoms although perceived air quality was worse at the higher temperature. The present results suggest that moderately elevated temperatures should be avoided even if thermal comfort can be achieved, as it may lead to reduced performance.
Li Lan; Lulu Xia; Rihab Hejjo; David P. Wyon; Pawel Wargocki. Perceived air quality and cognitive performance decrease at moderately raised indoor temperatures even when clothed for comfort. Indoor Air 2020, 30, 841 -859.
AMA StyleLi Lan, Lulu Xia, Rihab Hejjo, David P. Wyon, Pawel Wargocki. Perceived air quality and cognitive performance decrease at moderately raised indoor temperatures even when clothed for comfort. Indoor Air. 2020; 30 (5):841-859.
Chicago/Turabian StyleLi Lan; Lulu Xia; Rihab Hejjo; David P. Wyon; Pawel Wargocki. 2020. "Perceived air quality and cognitive performance decrease at moderately raised indoor temperatures even when clothed for comfort." Indoor Air 30, no. 5: 841-859.
Ammonia (NH3) is typically present at higher concentrations in indoor air (~ 10 - 70 ppb) than in outdoor air (~ 50 ppt - 5 ppb). It is the dominant neutralizer of acidic species in indoor environments, strongly influencing the partitioning of gaseous acidic and basic species to aerosols, surface films, and bulk water. We have measured NH3 emissions from humans in an environmentally controlled chamber. A series of experiments, each with four volunteers, quantified NH3 emissions as a function of temperature (25.1 to 32.6 °C), clothing (long-sleeved shirts/pants or T-shirts/shorts), age (teenagers, adults, seniors), relative humidity (low or high) and ozone (< 2 ppb or ~ 35 ppb). Higher temperature and more skin exposure (T-shirts/shorts) significantly increased emission rates. For adults and seniors (long clothing), NH3 emissions are estimated to be 0.4 mg h-1 person-1 at 25 °C, 0.8 mg h-1 person-1 at 27 °C, and 1.4 mg h-1 person-1 at 29 °C, based on the temperature relationship observed in this study. Human NH3 emissions are sufficient to neutralize the acidifying impacts of human CO2 emissions. Results from this study can be used to more accurately model indoor and inner-city outdoor NH3 concentrations and associated chemistry.
Mengze Li; Charles J. Weschler; Gabriel Bekö; Pawel Wargocki; Gregor Lucic; Jonathan Williams. Human Ammonia Emission Rates under Various Indoor Environmental Conditions. Environmental Science & Technology 2020, 54, 5419 -5428.
AMA StyleMengze Li, Charles J. Weschler, Gabriel Bekö, Pawel Wargocki, Gregor Lucic, Jonathan Williams. Human Ammonia Emission Rates under Various Indoor Environmental Conditions. Environmental Science & Technology. 2020; 54 (9):5419-5428.
Chicago/Turabian StyleMengze Li; Charles J. Weschler; Gabriel Bekö; Pawel Wargocki; Gregor Lucic; Jonathan Williams. 2020. "Human Ammonia Emission Rates under Various Indoor Environmental Conditions." Environmental Science & Technology 54, no. 9: 5419-5428.
The data from published studies were used to derive systematic relationships between learning outcomes and air quality in classrooms. Psychological tests measuring cognitive abilities and skills, school tasks including mathematical and language-based tasks, rating schemes, and tests used to assess progress in learning including end-of-year grades and exam scores were used to quantify learning outcomes. Short-term sick leave was also included because it may influence progress in learning. Classroom indoor air quality was characterized by the concentration of carbon dioxide (CO2). For psychological tests and school tasks, fractional changes in performance were regressed against the average concentrations of CO2 at which they occurred; all data reported in studies meeting the inclusion criteria were used to derive the relationship, regardless of whether the change in performance was statistically significant at the examined levels of classroom air quality. The analysis predicts that reducing CO2 concentration from 2,100 ppm to 900 ppm would improve the performance of psychological tests and school tasks by 12% with respect to the speed at which the tasks are performed and by 2% with respect to errors made. For other learning outcomes and short-term sick leave, only the relationships published in the original studies were available. They were therefore used to make predictions. These relationships show that reducing the CO2 concentration from 2,300 ppm to 900 ppm would improve performance on the tests used to assess progress in learning by 5% and that reducing CO2 from 4,100 ppm to 1,000 ppm would increase daily attendance by 2.5%. These results suggest that increasing the ventilation rate in classrooms in the range from 2 L/s-person to 10 L/s-person can bring significant benefits in terms of learning performance and pupil attendance; no data are available for higher rates. The results provide a strong incentive for improving classroom air quality and can be used in cost-benefit analyses.
Pawel Wargocki; Jose Ali Porras-Salazar; Sergio Contreras-Espinoza; William Bahnfleth. The relationships between classroom air quality and children’s performance in school. Building and Environment 2020, 173, 106749 .
AMA StylePawel Wargocki, Jose Ali Porras-Salazar, Sergio Contreras-Espinoza, William Bahnfleth. The relationships between classroom air quality and children’s performance in school. Building and Environment. 2020; 173 ():106749.
Chicago/Turabian StylePawel Wargocki; Jose Ali Porras-Salazar; Sergio Contreras-Espinoza; William Bahnfleth. 2020. "The relationships between classroom air quality and children’s performance in school." Building and Environment 173, no. : 106749.
A cross-sectional study was conducted in Singapore to investigate whether buildings refurbished to attain the Green Mark (GM) standards present measurable improvements to indoor environmental quality (IEQ) that are also manifested by the occupants with respect to their level of satisfaction and health symptoms. Comparative analyses were performed with buildings that are GM-certified since day one (GMN), buildings refurbished to GM standards (GMC) and conventional buildings which could not receive the GM certification (NGM). A one-week field measurement of selected IEQ parameters and post occupancy surveys of satisfaction and health symptoms of 367 occupants in 14 office buildings revealed that GMC buildings exhibited levels of IEQ, satisfaction and health symptoms similar to GMN buildings. Both categories of buildings had superior IEQ compared with NGM buildings. Apart from parameters affected by limitations of refurbishment related to façade, this study found that enhanced IEQ performance to the level as high as GMN buildings’ can be achieved by converting existing conventional buildings to GM-certified buildings through green refurbishment in the context of office buildings in Singapore.
Jang-Young Lee; Pawel Wargocki; Yiong-Huak Chan; Liu Chen; Kwok Wai Tham. How does indoor environmental quality in green refurbished office buildings compare with the one in new certified buildings? Building and Environment 2020, 171, 106677 .
AMA StyleJang-Young Lee, Pawel Wargocki, Yiong-Huak Chan, Liu Chen, Kwok Wai Tham. How does indoor environmental quality in green refurbished office buildings compare with the one in new certified buildings? Building and Environment. 2020; 171 ():106677.
Chicago/Turabian StyleJang-Young Lee; Pawel Wargocki; Yiong-Huak Chan; Liu Chen; Kwok Wai Tham. 2020. "How does indoor environmental quality in green refurbished office buildings compare with the one in new certified buildings?" Building and Environment 171, no. : 106677.