From the Editor: COVID control case studies special issue

Throughout the COVID-19 pandemic, the expertise of industrial hygienists and allied professionals provided critical insights into steps to minimize the spread of the SARS-CoV-2 virus. Discussions among aerosol experts and health care practitioners regarding the mere definition of the term “aerosol” required substantial education, helping to communicate that particles smaller than just liquid “droplets” could harbor and spread the virus. The pandemic raised awareness of the benefits of face filtering respirators—now identified by the media and the mask-wearing public as N95s—compared to cloth and ill-fitting surgical type face covers. This pandemic also highlighted the need for understanding and improving ventilation to increase fresh air exchange into occupied spaces, to protect both workers and the general public.

In September 2021, the JOEH issued a special request for short reports: case studies that evaluated the effectiveness of controls during the COVID pandemic. The goal was to capture the variety of techniques used to make decisions during an uncertain time, when pressures to understand and minimize risks were high so that businesses, schools, and society could “return to normal.” We asked for case studies that would be of interest to our readers and include investigations that examined methods to quickly assess ventilation performance, aerosol transport studies in workspaces, flow studies around plexiglass barriers in the workplace, and effectiveness of local HEPA filtration units in shared spaces. We are pleased to have prepared this special issue in response.

While these case studies may have limited generalizability, particularly given the diversity of workspaces investigated by occupational hygienists, we want to capture these case studies to document methods that may help future assessments. Authors were asked to clearly state the study’s research question and objective, fully explain the workspaces examined (dimensions, anticipated occupancy, pre-COVID ventilation systems), and the methods deployed to perform assessments that investigate how to control the spread of the SARS-CoV-2 virus. Because these methods were deployed in the real-world environment with less than usual study design forethought, we simply asked authors to clearly explain the methods used, to a degree that someone could repeat the study on their own (equipment, deployment period, data processing, decision criteria used for assessment) and explain the limitations to the study, given the limited resources or access to additional resources during the pandemic. We also asked authors to include thoughts about the “decisions made” from this case study and to provide guidance and cautions about using this method in other settings, as appropriate.

Consequently, we received many papers, including an observational study of controls in public spaces (Baker et al.) and surveys in medical examiners/coroners’ offices (Attwood et al.), altered methods to test respirator/mask performance (Popov), and lab testing to recommend reduced aerosols from toilet flushing (Cai et al.), particularly relevant when virus presence was detected in feces of infected patients. Two studies (Blackley et al., Howe et al.) included in this issue investigate aerosol transport in dental offices, necessary to protect patients and staff when work necessitates unmasked patients. Two more studies present using carbon dioxide as a tracer gas to investigate air exchanges in schools (Peters et al.) and on buses (VanDyke et al.). Additional studies examining portable air purifiers (Quam et al.) and ventilation effectiveness in outdoor dining enclosures (Persing et al.) are also included.

I want to thank everyone who helped pull together this special issue. I extend my thanks to authors and reviewers who provided a quick but thorough turnaround so we could publish these studies as the (fingers crossed) pandemic winds down. I also want to thank our Guest Editor, Dr. Lisa Brosseau. Early in the pandemic, she identified a need to solicit control technology papers for JOEH, and she graciously coordinated reviews for papers from my home institution, maintaining double-blind reviews which are integral to the JOEH peer-review process.

Finally, and most importantly, I hope that the techniques presented in these case studies, while limited in their application and scope, can provide guidance for future exposure control assessments.

T. Renée Anthony
Editor-in-Chief, JOEH [email protected]