Status and Prediction of SO 2 as an Air Pollutant in Shiraz,Iran

In the present study air quality analyses for sulfur dioxide (SO₂), were conducted in Shiraz, a city in the south of Iran. The measurements were taken from 2011 through 2012 in two different locations to prepare average data in the city. The average concentrations were calculated for every 24 hours, each month and each season. Results showed that the highest concentration of SO₂ occurs generally in the morning while the least concentration was found at the afternoon and mid-night. Monthly concentrations of SO₂ showed the highest value in June while the least value in February. The seasonal concentrations showed the least amounts in autumn while the highest amounts in summer. Relations between the air pollutants and some meteorological parameters were calculated statistically using the daily average data. The wind data (velocity, direction), relative humidity, temperature, sunshine periods, evaporation, dew point and rainfall are considered as independent variables. The relationships between concentration of pollutant and meteorological parameters were expressed by multiple linear regression equations for both annual and seasonal conditions using SPSS software. RMSE test showed that among different prediction models, stepwise model is the best option.