Evidence for Ultraviolet Radiation Decreasing COVID-19 Growth Rates: Global Estimates and Seasonal Implications

46 Pages Posted: 12 May 2020 Last revised: 17 Jun 2020

See all articles by Tamma Carleton

Tamma Carleton

University of Chicago

Jules Cornetet

École Normale Supérieure Paris-Saclay

Peter Huybers

Harvard University

Kyle Meng

University of California, Santa Barbara (UCSB) - Donald Bren School of Environmental Science & Management

Jonathan Proctor

Harvard University

Date Written: April 28, 2020

Abstract

With nearly every country now combating the 2019 novel coronavirus (COVID-19), there is a growing need to understand how local environmental conditions may modify transmission. To date, quantifying seasonality of the disease has been limited by scarce data and the difficulty of isolating climatological variables from other drivers of transmission in observational studies. We combine a spatially-resolved dataset of confirmed COVID-19 cases, composed of 3,235 regions across 173 countries, with local environmental conditions and a statistical approach developed to quantify causal effects of environmental conditions in observational data settings. We find that ultraviolet (UV) radiation has a statistically significant effect on daily COVID-19 growth rates: a standard deviation increase in UV lowers the daily growth rate of COVID-19 cases by approximately 1 percentage point over the subsequent 2.5 weeks, relative to an average in-sample growth rate of 13.2 percent. The time pattern of lagged effects peaks 9-11 days after UV exposure, consistent with the combined timescale of incubation, testing, and reporting. Cumulative effects of temperature and humidity are not statistically significant. Simulations illustrate how seasonal changes in UV have influenced regional patterns of COVID-19 growth rates from January to June. However, total COVID-19 seasonality had indeterminate sign for most regions during this period due to uncertain effects of other environmental variables. Thus, while our findings indicate UV exposure influences COVID-19 cases, a comprehensive understanding of seasonality awaits further analysis.

Note: Funding: None.

Conflict of Interest: The authors declare no conflicts of interest.

Ethical Approval: No human participants or animals were used in this study, and no personally identifiable information was collected or analyzed.

Keywords: climate, COVID-19, coronavirus, econometrics, ultraviolet radiation

JEL Classification: H51, H75, I1, Q5

Suggested Citation

Carleton, Tamma and Cornetet, Jules and Huybers, Peter and Meng, Kyle and Proctor, Jonathan, Evidence for Ultraviolet Radiation Decreasing COVID-19 Growth Rates: Global Estimates and Seasonal Implications (April 28, 2020). Available at SSRN: https://ssrn.com/abstract=3588601 or http://dx.doi.org/10.2139/ssrn.3588601

Tamma Carleton (Contact Author)

University of Chicago ( email )

1101 East 58th Street
Chicago, IL 60637
United States
7737026763 (Phone)

Jules Cornetet

École Normale Supérieure Paris-Saclay ( email )

61 avenue du président Wilson
Cachan, Paris 94235
France

Peter Huybers

Harvard University ( email )

1875 Cambridge Street
Cambridge, MA 02138
United States

Kyle Meng

University of California, Santa Barbara (UCSB) - Donald Bren School of Environmental Science & Management ( email )

4670 Physical Sciences North
Santa Barbara, CA 93106-5131
United States

Jonathan Proctor

Harvard University ( email )

1875 Cambridge Street
Cambridge, MA 02138
United States

Here is the Coronavirus
related research on SSRN

Paper statistics

Downloads
384
Abstract Views
1,731
rank
85,204
PlumX Metrics