Table 2.

Pearson correlation coefficients between air pollution concentrations and weather conditions in Beijing, 2013–2017

	CO	PM2.5	SO2	NO2	O3	Temperature	Relative humidity
CO	1.000
PM2.5	0.830*	1.000
SO2	0.670*	0.562*	1.000
NO2	0.820*	0.786*	0.633*	1.000
O3	−0.379*	− 0.149*	− 0.338*	− 0.383*	1.000
Temperature	−0.398*	− 0.183*	− 0.488*	− 0.354*	0.768*	1.000
Relative humidity	−0.028	−0.015	− 0.277*	− 0.017	0.029	0.135*	1.000
Air pressure	0.246*	0.061*	0.316*	0.221*	− 0.691*	− 0.875*	− 0.090*

* P < 0.001

CO carbon monoxide, PM_2.5 particulate matter with aerodynamic diameter less than 2.5 μm, SO₂ sulfur dioxide, NO₂ nitrogen dioxide, O₃ ozone