| Johns Hopkins University Center for Systems Science and Engineering Coronavirus Resource Center (CSSE) [2] |
Cumulative county-level confirmed cases and deaths up to March 25th, 2022 |
| Covid Act Now [27] |
Cumulative county-level number of people completely vaccinated and number of completed vaccinated people receiving booster up to March 11th, 2022 |
| Atmospheric Composition Analysis Group [28] |
Annual average PM2.5 concentration between 2000 and 2018 |
| The US Census/American Community Survey |
County-level socioeconomic and demographic variables in 2020 |
| The County Health Rankings & Roadmaps program [29] |
Country-level behavioral variables and rural/urban status in 2020 |
| Boston University of Public Health [30] |
State-level policy of face masks mandates and stay home orders before July 2nd, 2022 |
