Investigating the Relationship between Air Pollutants and Meteorology: A Canonical Correlation Analysis

In order to characterize the most important meteorological parameters that determine air pollutants' behavior, canonical correlation analysis was conducted. Meteorological parameters include temperature, rainfall, relative humidity, wind speed and wind direction. On the other hand, air pollutants include O3, NO, NO2, SO2, CO, CH4, non-methane hydrocarbons (NMHC) and PM10. The study was conducted in Mosul city, northern Iraq. The data were collected using a fixed monitoring station and ultrasonic weather station placed on the side of a separate main heavy traffic road. The first two canonical functions extracted by the analysis explained more than 95% of the variance in air pollutants. The first canonical function shows high canonical correlation coefficient between its pair canonical variates (0.849, p<0.001), versus 0.445 (p<0.001) between the pair variates of the second function. The results of the canonical correlation analysis highlighted that temperature was the major contributor in the explanatory capacity of meteorological parameters compared with the other parameters. On the other hand, ozone had a major contribution to the explanatory capacity of air pollutants compared with the other pollutants. The major conclusion is the ability of canonical correlation analysis to reduce the input parameters mainly to temperature and ozone in this study.