Investigating the Relationship between AQI Pollutants and Meteorological Parameters in Severe Inversions of Tabriz, Iran

Air pollution is one of the major problems in Tabriz, Iran. One of the natural factors involved in air pollution is Temperature inversion which is an effective factor in urban environments therefore the purpose of this study is to investigate the significance relationship between concentration of particulate matter (PM10), carbon monoxide and dioxide sulfur with meteorological parameters such as horizontal vision, pressure, relative humidity, temperature, wind speed, maximum wind speed, KI index, the height of the top of temperature inversion layer, depth and intensity of temperature inversion. Therefore, a 5-year period, from 2008 to 2013 was considered and pollution conditions of Tabriz in the days of inversion were studied using skew-t maps. In order to investigate the relationship between the concentration of pollutants with the properties of temperature inversion layer, climatic parameters and atmospheric stability Pearson correlation was used. Also, multivariate step-wise linear regression was used to indicate the variables which had a greater role in the increase or decrease of the concentration of pollutants. The results showed that the amount of PM10 is significantly related to the intensity of inversion and pressure, CO with inversion intensity, pressure and relative humidity, SO2 with inversion intensity and temperature. Multivariate stepwise regression analysis showed that the intensity of the thermal inversion is the only variable that is positively related to all three pollutants, which indicates the effect of inversion layer’s intensity on the trend of air pollution and intensification of pollutants concentration. Also, relative humidity and temperature after temperature inversion were the most effective elements on the trend of CO and SO2 pollutants. As a result, variables such as inversion intensity, temperature, relative humidity and pressure had greatest impact on the concentration of pollutants.