Path analysis approach to quantify the causal factors of ground-level ozone concentration near coal-mining regions

Abstract

Ground‐level ozone (GLO) is a secondary air pollutant, and thus the quantification of the causal factors is a challenging task. The present study aims to quantify the effect of primary air pollutants (NO2, NO, PM2.5, PM10, SO2, CO, NEPH) and meteorological factors (solar radiation, air temperature, wind speed, wind direction, standard deviation in wind direction, rainfall and humidity) on GLO concentration near coal-mining area. Path analysis approach is used to estimate both the magnitude and significance of causal connections between dependent and independent variables. The results indicate that the direct effects of NO, NO2, NEPH, wind speed, humidity, SD1 and RNF on GLO concentration are significant (p < 0.05). It is interesting to note that GLO is significantly influenced by two primary air pollutants (NO and NO2) in all the three locations (Wallsend, Beresfield and Newcastle). The influences of NEPH, wind speed, humidity, standard deviation in wind direction and rainfall on GLO were also found to be significant (p < 0.05) but not for all the locations. The level of direct effects of NO on GLO is found to be maximum, and the values are − 0.497, − 0.456 and − 0.461, respectively, for Wallsend, Newcastle and Beresfield monitoring stations. Majority of the significant primary pollutants and meteorological parameters show a consistent trend in terms of positive and negative influences on GLO concentration. These findings contribute to the control of GLO concentration which is mainly driven by primary causal factors in the atmosphere.