Fig. 3: Correlation heatmap of air quality and meteorological variables.

The closer a color is to red end of the spectrum, the stronger the positive correlation it indicates. Similarly, the closer it is to blue end of the spectrum, the stronger the negative correlation it indicates. AQI: Air Quality Index; CO: Carbon Monoxide; NO2: Nitrogen Dioxide; PM10: Particulate Matter with a diameter of 10 micrometers or less; PM2.5: Fine Particulate Matter with a diameter of 2.5 micrometers or less; SO2: Sulfur Dioxide.