Table 2.

Spearman correlation coefficient between air pollutants and COVID-19 case numbers.

Climatic variables	Correlation coefficient	p-value
PM2.5	0.34	0.0032
PM10	−0.21	0.072
O3	−0.33	0.0043
NO2	0.54	<0.001
CO	−0.12	0.31
SO2	−0.12	0.32
PSI	0.35	0.0020
Temperature	0.45	<0.001
Rainfall	−0.23	0.049
Humidity	−0.032	0.79

Abbreviations: NO₂: nitrogen dioxide, SO₂: sulphur dioxide, CO: carbon monoxide, O₃: ozone, PSI: pollutant standards index, PM_2.5: particulate matter with a diameter of 2.5 μm or less, PM₁₀: particulate matter with a diameter of 10 μm or less.