The project aimed to make an inventory of hands-on ventilation and air cleaning advice that was shared with the general public and e.g. facility managers and building owners during the 2 years of the COVID pandemic. An online search resulted in 188 documents from 16 countries. Many documents addressed the importance of adequate ventilation but did not present concrete advice on how or how much to ventilate to make spaces 'covid safe enough'. Several documents mention the options of CO2 monitoring but only as a rudimentary mean to estimate airborne infection risks. A substantial amount of documents explained that also air cleaning technology can help to decrease infection risks. But not as a substitute for regular fresh air supply, more as an addition to it. Some documents mentioned the effect of (increased) temperature and ditto humidity on virus survival rates but most do not give specific recommendations about setpoint changes. On the other hand, several documents do give concrete advice on other HVAC system settings related to e.g. operating hours, recirculation or pressure balances. The outcomes of this study will be used to help construct a new set of Dutch infographics and guidelines that should help non-technical decision makers to better understand how one can use ventilation and air cleaning technologies to decrease airborne infection risks inside. ... Read more

Voor dit onderzoek is data verzameld door middel van sleuteldocumenten, interviews en enquêtes. Alle stakeholders zijn individueel geïnterviewd in november 2022 middels een semigestructureerd interview. Hierbij zijn sleuteldocumenten gebruikt om de positie van een bepaalde stakeholdersgroep inzake warmtenetten te kennen, zoals positionpapers van brancheverenigingen of beleidsdocumenten.

Uit de interviews met de stakeholders zijn onzekerheden geïdentificeerd. Een samenvatting van de geïdentificeerde onzekerheden is ter verificatie aangeboden aan de geïnterviewde stakeholders. Vanuit alle geïdentificeerde onzekerheden heeft het onderzoeksteam een inschatting gemaakt welke onzekerheden van toepassing konden zijn voor een bepaalde stakeholdersgroep. Hierbij zijn de volgende stakeholdergroepen gedefinieerd: gemeente, warmtebedrijven, warmteproducent en projectontwikkelaars.

Vervolgens hebben stakeholders per enquête geverifieerd of de stakeholdersgroep bloot wordt gesteld aan de voorgelegde onzekerheden. Daarbij wordt er van uitgegaan dat als, bijvoorbeeld, één projectontwikkelaar aangaf dat zij aan een onzekerheid wordt blootgesteld, die onzekerheid van toepassing is op de gehele groep van projectontwikkelaars.

De primaire doelgroep voor dit whitepaper zijn gemeenten, maar ook voor andere stakeholders die betrokken zijn bij de ontwikkeling van een warmtenet zijn er zinvolle lessen te trekken. ... Read more

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. ... Read more

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. ... Read more