Informing Building Strategies to Reduce Infectious Aerosol Transmission Risk by Integrating DNA Aerosol Tracers with Quantitative Microbial Risk Assessment

Abstract

Using aerosol-based tracers to estimate risk of infectious aerosol transmission aids in the design of buildings with adequate protection against aerosol transmissible pathogens, such as SARS-CoV-2 and influenza. We propose a method for scaling a SARS-CoV-2 bulk aerosol quantitative microbial risk assessment (QMRA) model for impulse emissions, coughing or sneezing, with aerosolized synthetic DNA tracer concentration measurements. With point-of-emission ratios describing relationships between tracer and respiratory aerosol emission characteristics (i.e., volume and RNA or DNA concentrations) and accounting for aerosolized pathogen loss of infectivity over time, we scale the inhaled pathogen dose and risk of infection with time-integrated tracer concentrations measured with a filter sampler. This tracer-scaled QMRA model is evaluated through scenario testing, comparing the impact of ventilation, occupancy, masking, and layering interventions on infection risk. We apply the tracer-scaled QMRA model to measurement data from an ambulatory care room to estimate the risk reduction resulting from HEPA air cleaner operation. Using DNA tracer measurements to scale a bulk aerosol QMRA model is a relatively simple method of estimating risk in buildings and can be applied to understand the impact of risk mitigation efforts.

Ratiometric Readout of Bacterial Infections via a Lyophilized CRISPR–Cas12a Sensor with Color-Changeable Bioluminescence

“…We still anticipated that both two-step and one-tube PEARL protocols may find their way for pathogen diagnostics. For example, one can choose the one-tube protocol if the aerosol contamination is a major concern, while the two-step protocol might be more suitable for outdoor detections because the outdoor environment can effectively alleviate the problem of aerosol contaminations . Moreover, it is also possible to achieve more efficient one-tube PEARL detection by combining PEARL with some controllable Cas12-sensing strategies, such as photoactivatable crRNA, choice of suboptimal PAMs in the amplification products, and use of a newly engineered Cas12b protein …”