This case study delves into the assessment of Sulfur dioxide (SO2) air pollution in Plovdiv by employing Multivariate Adaptive Regression Splines (MARS) to model and understand the factors influencing daily SO2 levels. By analyzing a dataset characterized by an average SO2 pollution level of 0.43ppm, this study highlights the potency of MARS in capturing the non-linear relationships and complex interactions between SO2 concentrations and measured meteorological and atmospheric time series in the form of quantitative and categorical variables. In particular, an increase in model performance is demonstrated by performing a modified Yeo-Johnson transformation on pollutant data and constructing additional predictors such as lag variables, date variable and dummies. A significant achievement of this investigation is the attainment of a coefficient of determination (R2) exceeding 0.91. This high level of accuracy highlights the efficiency of MARS as a flexible and reliable machine learning tool thus emphasizing its potential in contributing to the urban air quality management toolbox.