Environmental Engineers Identify Factors Affecting COVID-19 Transmission

March 30th 2020
Aislinn Antrim, Assistant Editor
Aislinn Antrim, Assistant Editor

The behaviors of viruses and how they react to various environments is highly variable, according to researchers at Stanford University.

Environmental engineers and other researchers are working to pinpoint the environmental factors that could affect the transmission of the coronavirus disease 2019 (COVID-19), in an effort to minimize dangerous environments and stem the spread.

The behaviors of viruses and how they react to various environments is highly variable, according to researchers at Stanford University. Some viruses can be transmitted through water and others are airborne, for example1. While the primary method of transmission for most enveloped viruses is via close contact with infected individuals, understanding the exact ways that COVID-19 can be transmitted is essential to slowing the spread and preventing more infections.1

Infections with severe acute respiratory syndrome coronavirus (SARS-CoV-2; the virus that causes COVID-19) are believed to be mainly spread via person-to-person contact and via exposure to droplets produced by sneezing or coughing, but the researchers noted that indirect routes may also be possible. Indirect transmission occurs when enveloped viruses are released into the environment by the host and continue to live on surfaces, in the air, or in water long enough to infect another host.1

“This potential role of the environment in the spread of COVID-19 highlights the multitude of applied research needs that must be addressed to effectively control outbreaks and pandemics as novel enveloped viruses emerge,” the researchers said in viewpoint published inEnvironmental Science and Technology1.

In addition to understanding how large of a role indirect transmission plays in the COVID-19 pandemic, the researchers added that various environmental conditions can influence how long the virus survives on various surfaces. Those conditions can include relative humidity, fomite material, and air temperature, and understanding these variations could help ensure properly cleaned surfaces and environments in which the virus is less likely to spread.1

The spread of COVID-19 via fecal contamination of water may be of particular concern. According to Alexandria Boehm, PhD, a Stanford professor and researcher on the project, increasing evidence has shown that the SARS-CoV-2 viruses, or at least their genomes, are excretes in feces, making fecal exposure a possible route of transmission.2

“It’s unlikely this could be a major transmission route, but a person could potentially be exposed by interacting with water contaminated with untreated fecal matter,” Boehm said in a statement from Stanford.2

Other research has shown that viruses similar to the SARS-CoV-2 viruses are susceptible to water treatment systems, but analyzing and pinpointing the exact risks could be vital during the COVID-19 pandemic, especially in regions of the world with less developed water treatment systems.2

Finally, the authors said there are many opportunities for collaboration between environmental scientists, environmental engineers, and health researchers during the rush to find more definitive answers on COVID-19 and its transmission. Krista Wigginton, MS, PhD, another researcher at Stanford, said that while COVID-19 is the major focus at the moment, taking a broader approach to many viruses could ensure a better understanding of their various environmental factors.2

“We tend to study viruses very intensely when there is an outbreak, but the results from one virus aren’t easy to extrapolate to other viruses that emerge 5 years later,” Wigginton said in the statement.2

Wigginton explained that while environmental engineers are analyzing pathogens outside of the host, virologists are studying what happens within the host cells, and public health researchers are trying to understand how the virus circulates within communities. Combining all of these viewpoints is going to be necessary to discover more about COVID-19.2


  1. Wigginton K, Boehm A. Environmental Engineers and Scientists Have Important Roles to Play in Stemming Outbreaks and Pandemics Caused by Enveloped Viruses.Environmental Science and Technology;March 24, 2020.https://pubs.acs.org/doi/10.1021/acs.est.0c01476#. Accessed March 30, 2020.
  2. Jordan R. Environmental engineers at Stanford discuss how to identify factors affecting COVID-19 transmission. Stanford News; March 26, 2020.https://news.stanford.edu/2020/03/26/understanding-spread-covid-19/. Accessed March 30, 2020.

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