The relationship between atmosphere temperature inversion and urban air pollution characteristics: A case for study Tehran, Iran

Abstract

Abstract This research aims to comprehensively assess the level of air pollution in Tehran, identify the primary sources of pollution, and explore potential solutions to mitigate this problem. To achieve this understanding, data was collected from Mehrabad station in Tehran city. In order to analyze the data and determine the dynamic and thermodynamic properties of the atmosphere, the research utilized the Universal radio sound Observation (RAOB) program. This program enabled the examination of the atmospheric properties up to an altitude of 750 meter during the selected days. Specifically, the research focused on three dates: January 22, 2014; January 25, 2015; and November 27, 2016. These dates were chosen as they represented the most polluted days, considering Tehran's seasonal variations and the adverse effects of cold weather and temperature drops on air pollution. The analysis of the collected data was performed using an equation that demonstrates the characteristics of the air temperature inversion profile. To assess the effects of atmospheric inversion on air pollution, the Heffter method was employed in this research. This method aimed to provide insights into how inversions impact air quality in Tehran. The results obtained from the analysis highlighted specific conditions on January 25, 2015, which was identified as the most polluted date. During the radiation inversion, the altitude above sea level measured 1227 meters, with an altitude above ground level of 36 meters. The potential temperature was recorded as 890 meter, relative humidity as 0%, and temperature as 2°C at pressure base (P1). At base altitude H1, the potential temperature at 886 meter, relative humidity was 36%, and temperature was 3°C. Additionally, the wind speed was measured at 2.1 m/s, wind direction at 280 degrees, and the inversion depth was calculated to be 18 meters.