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Coronavirus and Environmental Engineering Science

Coronavirus and Environmental Engineering Science

Coronavirus and Environmental Engineering Science

April 8, 2020


The ongoing outbreak of coronavirus disease resulting from the emergence of the virus severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) is a matter of major global concern and threatens to rival consequences from the 1918 to 1919 influenza outbreak. Although this has resulted in a rapid mobilization of resources from the medical and public health communities, there are major roles to play for those of us in environmental engineering and science (EES).

EES researchers and practitioners have strong quantitative skills in describing how contaminants move from sources (infected individuals), transport and decay in the environment (in the air, on fomites), and ultimately result in exposure to a receptor (susceptible individual). In the context of bioaerosols such as SARS-COV-2, source terms of the generated airborne particles themselves can be characterized (Tang et al., 2013; Yan et al., 2018; Lee et al., 2019). In a general sense, factors that influence persistence of viruses in airborne particles in the indoor environment are known (Marr et al., 2019). Larger airborne particles (often called "droplets" in the epidemiologic literature) can be directly deposited on sensitive sites on the receptor (nose, eye, and mouth), whereas smaller particles that remain suspended in air for longer periods can be inhaled. Dynamics of indoor airborne particles containing biological materials are well known (Nazaroff, 2014). Breaking data indicate that decay rates of the SARS-COV-2 virus are similar to those of the SARS virus (van Doremalen et al., 2020).

Larger airborne particles can deposit on surfaces where the contained viruses persist for hours to days (Casanova et al., 2010; van Doremalen et al., 2020)—these are called fomites. With the SARS outbreak, fomites were a route of transmission (Xiao et al., 2017). Analyses of the fomite to hand to (eye, mouth, and nose) pathway are necessary to assess significance. But this is akin to multi-path exposure calculations done in other realms of EES.

Given exposure, health risk can be assessed using the standard concepts of risk assessment applied to microorganisms; quantitative microbial risk assessment (QMRA) has been practiced for ∼40 years (Haas et al., 2014). For aerosols, size-specific corrections for retention can be made (Teske et al., 2014). With both SARS (Watanabe et al., 2010) and Middle Eastern respiratory syndrome (Adhikari et al., 2019), QMRA has been shown to be useful.

There are a number of engineering interventions that might be useful in risk reduction, including air filtration, ventilation, and inactivation (such as by ultraviolet light).

The mentioned tools should be familiar in the toolbox of EES. Applied to the present global pandemic, EES researchers and practitioners must not be timid in applying them to effect restoration and improvement of the publics' health.