Analyzing the influence of the Planetary Boundary Layer Height, Ventilation Coefficient, Thermal Inversions, and Aerosol Optical Depth on the concentration of PM2.5 in the city of São Paulo: A Long-term study

Cases of intense air pollution have been a recurring problem in most of urban centers in different regions of the world. Although actions to mitigate pollutant emissions are fundamental, it is also necessary to understand which factors can favor their dispersion process. In this scenario, this paper presents, for the first time, a long-term analysis of the Planetary Boundary Layer Height (), estimated through lidar and radiosounding data, Ventilation Coefficient (), Thermal Inversions (), and Aerosol Optical Depth (), for the city of São Paulo, demonstrating how these variables are related with concentration. The analyzes showed that and have a seasonal cycle, with higher values in summer and lower ones in winter. Furthermore, is affected by one local factor, the sea-breeze, which reduces the concentration of aerosols in the late afternoon, resulting in an underestimated obtained from lidar data. Furthermore, from AERONET data, a predominance of Black Carbon and small particles was observed in all seasons, which are associated with the feedback effect observed in winter. Such effect attenuates the increase of and in cases of high concentrations of . Finally, it was presented a Generalized Linear Model, which combines , and information as input and can estimate the concentration with a R2 = 0.93.