Weekend effect on air pollutant levels in southernmost cities of Brazil with different economic activities.

In view of the current premises of the need to investigate air pollution in small- and medium-sized cities, combined with concerns regarding the weekly behavior of air pollutants, this study aimed to investigate the weekly pattern of air pollution (O, NO, SO, PM) and the weekend effect in 4 Brazilian cities with different main economic activities. Our main findings include (1) positive weekend effect for all the assessed air pollutants in the four cities; therefore, in the southernmost region of Brazil, there was an increase in the concentration of air pollutants during weekends when compared to weekdays; (2) the highest levels of NO and SO were observed in the city characterized by the economic activity revolving around coal mining and generation of electricity through the burning of this mineraloid in a coal-fired power plant, while the highest levels of PM were in the city with economic activity linked to industries, due to its recognized industrial complex; and (3) the seasonal evaluation of the weekend effect showed different behaviors for the air pollutants in each location, which is related to the set of meteorological conditions, economic activities, and population mobility in each location. In conclusion, our results demonstrate the aspects of pollution between cities and highlight that the comprehensive understanding of the weekend effect and its intricacies allows the responsible personal and government authorities to gain deep insights into the true effectiveness of future control strategies and the development of possible action plans.