With exposure to sunlight (UV 1.5-12): temperature 68☏ and relative humidity 20%.

Without exposure to sunlight (UV 0): temperature (74☏ to 95☏) and relative humidity from 20-60%.

This tool is valid for the following ranges of conditions:

Contact Hazard (how much virus comes off from touching surfaces).

Virus shedding is unknown (how much a sick person puts into the environment).

Infectious dose is unknown (how much makes a person sick).

For additional information and details on methodology, please see the article titled, “Simulated Sunlight Rapidly Inactivates SARS-CoV-2 on Surfaces” published in the Journal of Infectious Diseases.

Research to determine impact of UV exposure on SARS-CoV-2 decay on surfaces was conducted at one temperature/relative humidity parameter.

For additional information and details on methodology for the research on the impact of temperature and relative humidity on SARS-CoV-2 decay on surfaces, please see the article titled, “Increasing Temperature and Relative Humidity Accelerates Inactivation of SARS-CoV-2 on Surfaces” published in the American Society for Microbiology journal.

There was no significant difference found in the decay of the virus found between stainless steel ABS plastic, and nitrile rubber.

Testing performed on non-porous surfaces, specifically stainless steel, ABS plastic, and nitrile rubber.

These data have been used to develop a predictive model to estimate virus decay under a limited range of environmental conditions.

Viral survival on surfaces is driven by temperature, relative humidity (RH), sunlight (UV), and matrix (e.g., bodily fluids).

DHS S&T has studied the stability of SARS-CoV-2 in simulated saliva, using droplets of varying size deposited on a non-porous surface under a range of temperature and RH conditions.

SARS-CoV-2 will survive in saliva and respiratory fluids on surfaces for extended periods of time under certain conditions.

Contact with contaminated surfaces and objects may also contribute to spread.

Transmission occurs primarily through respiratory droplets produced by talking, coughing and sneezing.

Preventing person-to-person spread of SARS-CoV-2 is the only means to reduce the impact of COVID-19 in the absence of an effective therapeutic.

The formula below was developed in ☌, but has been modified in the web calculator to use ☏. The predictive power is limited to temperature between 74-95☏ and relative humidity between 20-60% for a UV index of 0, and a temperature of 68☏ and 20% relative humidity for a UV index between 1.5 and 12. Relative humidity, temperature, and sunlight (UV) can be used to provide an estimated half-life for SARS-CoV-2 with this model with some degree of certainty. * Note: Temperature (68☏) and relative humidity (20%) input cannot be changed for UV values greater than 0.

Surface tension half life