Transmission of SARS?CoV?2 by inhalation of respiratory aerosol in the Skagit Valley Chorale superspreading event

During the 2020 COVID‐19 pandemic, an outbreak occurred following attendance of a symptomatic index case at a weekly rehearsal on 10 March of the Skagit Valley Chorale (SVC). After that rehearsal, 53 members of the SVC among 61 in attendance were confirmed or strongly suspected to have contracted COVID‐19 and two died. Transmission by the aerosol route is likely; it appears unlikely that either fomite or ballistic droplet transmission could explain a substantial fraction of the cases. It is vital to identify features of cases such as this to better understand the factors that promote superspreading events. Based on a conditional assumption that transmission during this outbreak was dominated by inhalation of respiratory aerosol generated by one index case, we use the available evidence to infer the emission rate of aerosol infectious quanta. We explore how the risk of infection would vary with several influential factors: ventilation rate, duration of event, and deposition onto surfaces. The results indicate a best‐estimate emission rate of 970 ± 390 quanta/h. Infection risk would be reduced by a factor of two by increasing the aerosol loss rate to 5 h−1 and shortening the event duration from 2.5 to 1 h

COVID-19 and Airborne Transmission: Science Rejected, Lives Lost. Can Society Do Better?

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 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

How can airborne transmission of COVID-19 indoors be minimised?

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

COVID-19 and Airborne Transmission: Science Rejected, Lives Lost. Can Society Do Better?

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 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

How can airborne transmission of COVID-19 indoors be minimised?

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.</p

Perceived control over indoor climate and its impact on Dutch office workers

A field study was conducted in nine modern office buildings in the Netherlands. The study focused on perceived control over indoor climate and its impact on satisfaction of building occupants, the incidence of building related (SBS) symptoms and self-assessed performance. The study involved a questionnaire amongst 236 office workers. Statistical analyses were conducted to investigate correlations between combined perceived control over temperature and ventilation on the one hand and satisfaction-, SBS- and productivity-indices on the other. Individual perceived control over indoor climate scores were perfectly normally distributed (using a 7 point scale coded from 1 = no control at all to 7 = full control) with as mean value 3.1 (SD 1.4). Respondents that perceived to have a high amount of control over their indoor climate were considerably more satisfied with their indoor environment. High control respondents also had significant less building related symptoms (BSI(5) 0.94 vs. 0.61). And productivity scores were significantly higher (6.3 %point) in comparison with the low control respondents

Qualit\ue9 de l'air interieur et confort dans les espaces de bureaux, et relations avec la performance au travail: Volet francais du projet OFFICAIR, Partie 2

The OFFICAIR project aimed to describe comfort and indoor air quality (IAQ) in new and retrofitted office buildings in Europe. In France, 21 office buildings participated in this project. In a subsample of five buildings, IAQ measurements and performance tests were carried out to study the relations between IAQ and work performance. Twenty-one compounds were measured (volatile organic compounds, aldehydes, nitrogen dioxide, and ozone) as well as environmental parameters: Carbon dioxide, temperature, and relative humidity, over five days in two different seasons. The occupants in the investigated rooms were invited to participate in two on-line task performance tests: A reaction time test, i.e., the standardized Deary-Liewald test, and a memory test. There were participants in summer and 98 in winter. They also provided self-assessments of the influence of the indoor environment on their productivity. The multilevel linear regression models showed that individual characteristics were the main factors determining performance at work. Indoor air concentrations of xylenes and ozone might influence reaction time during summer. Both in summer and winter, the occupants' satisfaction regarding noise and their perceived ability to control their indoor temperature increased their self-assessed productivity. This work is the first to study the influence of IAQ on performance in real work environments and on the basis of IAQmeasurements. This study was limited to five buildings, but it would be useful to repeat it on a larger scale