Living through the COVID-19 pandemic has been challenging. It has required us all to change our normal habits and adapt to a new way of doing things. Teleworking full-time from home, social distancing, wearing face masks in public and staying put at home for an extended time are things we never really thought we would have to do. As we head into summer and think about our plans, naturally we turn our attention to the outdoors. After spending a lot of time inside over the past few months, and with warmer weather upon us, many are feeling the urge to get out—let’s explore some S&T research and federal guidelines that will help you do it safely.
June is Great Outdoors Month, a time in which people are encouraged to explore all that nature has to offer, including our nation’s wildlife refuges or parks. This commemoration began as ‘Great Outdoors Week’ in 1998 under President Clinton and has grown into a longer celebration under the Bush, Obama and Trump administrations. Governors all over the country have come together to designate June as a month to celebrate the great outdoors.
Science shows that spending time outdoors does wonders for your health. Since the beginning of the COVID-19 pandemic, our National Biodefense Analysis and Countermeasures Center (NBACC) has been working tirelessly to study environmental factors—sunlight, temperature, humidity—and decontamination effectiveness. NBACC’s research focuses on survivability of the virus on commonly-used surfaces, in the air, and in human saliva and respiratory fluids. The emerging results will provide insight into the safety of outdoor (and indoor) spaces in relation to the virus and on corresponding mitigation strategies.
One of the studies, “Simulated Sunlight Rapidly Inactivates SARS-CoV-2 on Surfaces” published late last month in The Journal of Infectious Diseases, provided the first evidence that sunlight may rapidly (in minutes) inactivate the coronavirus on surfaces as compared to in darkness, which can take hours and even days. Therefore, exposure risk outdoors may be much smaller than indoors.
Another NBACC study tested how sunlight affects the coronavirus in aerosols—tiny droplets that form when we sneeze, breathe and talk. This study, “Airborne SARS-CoV-2 is Rapidly Inactivated by Simulated Sunlight,” was published just last week in the same journal. This, too, showed that sunlight has a quick, detrimental effect on the virus. Additional journal studies currently in peer-review that highlight similar effects of temperature and relative humidity are expected to be published soon; in the meantime, we shared preliminary findings here.
In addition to the studies, we recently also launched two related interactive predictive modeling tools to assist response efforts and estimate the persistence of the virus on surfaces and in aerosols under certain combinations of sunlight, temperature and humidity. The new SARS-CoV-2 Natural Decay Calculator shows how long it takes for the virus to decrease in number on surfaces like stainless steel, ABS plastic (cell phones, computer keyboards, computer mouse), and nitrile rubber (disposable gloves). The SARS-CoV-2 Airborne Decay Calculator shows virus stability in aerosols generated from saliva across a range of environmental conditions.
For most of us, this NBACC research is music to our ears, as it indicates that simply being outside does not put us at increased risk for COVID-19. Although sunlight, temperature and humidity can affect the life span of the virus, we still need to be sure that as we emerge from our state of quarantine and spend time in the great outdoors we continue to heed the guidance set forth by the White House, DHS and Centers for Disease Control and Prevention—stay at least 6 feet apart, wear a face mask, and avoid clustering in crowded places and mass gatherings. Stay safe, and don’t forget your sunscreen!