Table 2

 Correlations between different air pollutants and meteorological variables

SO2NO2PM10O3PM2.5TemperatureHumidity
r, Pearson correlation coefficient; SO2, sulphur dioxide; NO2, nitrogen dioxide; O3, ozone; PM10, PM2.5, particulates with an aerodynamic diameter <10 μm or <2.5 μm.
SO2r1.000.659*0.229*−0.037*0.2820.084*0.169*
p value<0.001<0.0010.111<0.001<0.001<0.001
NO2r1.000.399*0.338*0.441−0.268*0.212*
p value<0.001<0.001<0.001<0.001<0.001
PM10r1.000.421*0.952−0.344*−0.390*
p value<0.001<0.001<0.001<0.001
O3r1.000.394−0.028−0.106*
p value<0.0010.236<0.001
PM2.5r1.00−0.356−0.343
p value<0.001<0.001
Temperaturer1.000.127*
p value0.001
Humidityr1.00
p value