Table 1.

Correlation (r) between COVID-19 variables and independent variables

Variable	Log PCI	Log PCD	CFR
Air pollution
AQI-total	0.110	0.079	0.035
AQI-Ozone	− 0.252	− 0.283	− 0.233
AQI-SO4	0.005	0.079	0.160
AQI-CO	0.225	0.272	0.175
AQI-NO2	0.464**	0.513**	0.399*
Race
Non-Hispanic Black or African American	0.119	0.112	0.035
Non-Hispanic American Indian or Alaska Native	− 0.281	− 0.403**	− 0.370*
Non-Hispanic Asian	0.112	0.135	0.078
Comorbidities
Total deathsa	0.286*	0.366**	0.328*
Pneumonia deathsa	0.647**	0.719**	0.642**
Influenza and pneumoniaa	0.355*	0.297*	0.295*
Nephritis nephrotic syndrome and nephrosisa	0.235	0.306*	0.294*
Other diseases of respiratory systema	0.383**	0.465**	0.411**
Septicemiaa	0.219	0.358**	0.358**
Socioeconomic-demographic
Log density	0.564**	0.652**	0.524**
HDI	0.230	0.218	0.188
GDP ($US)	0.395**	0.375**	0.224
Median age	− 0.084	0.131	0.357**
Longitude (°)	− 0.569**	− 0.612**	− 0.446**

Other race or comorbidities not significant with low correlation coefficient. ** P < 0.01, *P < 0.05

AQI air quality index, PCP proportion of cases to population per 10⁵, PDP proportion of deaths to population per 10⁵, CFR case fatality rate (%), HDI human development index, GDP gross domestic product per capita ($US)

^aDeaths for 22 weeks as up June 6, 2020, per 10⁵ population