How does it spread?
Most scientist and public health organizations agree that there are two main ways that COVID-19 can spread:
- COVID-19 is thought to spread mainly through close contact from person-to-person through inhalation of large respiratory droplets or direct contact(1).
- And through touching infected surfaces and touching your face, rubbing your eyes, picking something up and eating it (4).
A third method of spread, more recently recognized, is inhaling small airborne droplets containing the COVID-19 virus (4). Airborne droplets are different from the large respiratory droplets that cause most spread of COVID-19. Large respiratory droplets usually cannot travel more than 6 feet (the recommended distance for social distancing) (1). Airborne droplets are small enough to stay suspended in the air and travel depending on air flow, up to several hours (5). While studies for airborne transmission of COVID-19 are still ongoing, more than 80 percent of published scientific journals indicate that COVID-19 can spread through the air and infect others (4). The WHO and the CDC have both updated their guidance to say that the COVID-19 virus can be spread through airborne particles. Multiple studies found that viruses are released during exhalation, talking, and coughing in microdroplets that are small enough to stay in the air and can travel a much further than the size of a typical room (5) For context on how small we're talking, about 400 COVID-19 virus particles can fit on the width of one of your hairs (8)! Particles that small can easily end up in our bodies and make us sick without proper protection.
How can you protect yourself from airborne COVID-19?
- Increase air flow: Making sure your indoor spaces get proper ventilation will help improve indoor air quality (2). The easiest way to do this is to open windows or screened doors as frequently as possible to keep air moving in the home (2). You can place a fan in front of the window or open windows on different sides of the house to help increase air flow. If you have a window air conditioner with an outdoor air intake or vent, turn that on as well (2). For bathrooms, turn the fan on when the bathroom is in use and keep it running, if possible (2).
- Use air filtration: air purifiers can help reduce airborne contaminants including viruses in a home or confined space (2). Consider purchasing air purifiers that have a portable high-efficiency particulate air (HEPA) fan/filtration system. Make sure air cleaners don't generate ozone (3). If you don't have access to an air filter, you can increase the filtration capacity of the filter capacity on your furnace to help (7). Most can support a MERV 13 filter.
- Be mindful of room capacity: Avoid overcrowding (5). If you are hosting a gathering, keep the number of guests invited small, and host the gathering outdoors, if possible (6). If a gathering needs to be indoors, keep doors and windows open for maximum airflow (6). Even when outdoors, be mindful of air flow. Try and avoid areas that have limited airflow (like standing in a corner between two buildings), if possible. And most importantly, don't forget to wear a mask if you're with people you don't live with!
While precautions to prevent airborne spread of COVID-19 are helpful, they are not the whole picture. The Environmental Protection Agency notes that when used along with other best practices recommended by the Centers for Disease Control and Prevention such as staying 6 feet away from others and mask wearing, increasing ventilation and air filtration is a good addition to helping prevent the spread of COVID-19.
All this to say, while COVID-19 is scary, there are things that we can do to help protect ourselves and our loved ones.
References
- https://www.epa.gov/coronavirus/indoor-air-and-coronavirus-covid-19
- https://www.epa.gov/coronavirus/frequent-questions-about-indoor-air-and-coronavirus-covid-19
- https://www.usgbc.org/credits/safety-first-138-v4.1
- https://www.sciencedirect.com/science/article/pii/S0160412020317876
- http://dominique.regards.free.fr/blog/images/documents_pdf/200602_l-Morawska_it-is-time-to-address-airborne-transmission-of-covid-19-clinical-infectious-diseases.pdf
- https://www.cdc.gov/coronavirus/2019-ncov/daily-life-coping/personal-social-activities.html
- https://www.ashrae.org/technical-resources/resources
- https://www.who.int/news-room/commentaries/detail/modes-of-transmission-of-virus-causing-covid-19-implications-for-ipc-precaution-recommendations
- https://www.fda.gov/medical-devices/coronavirus-covid-19-and-medical-devices/uv-lights-and-lamps-ultraviolet-c-radiation-disinfection-and-coronavirus
