Future Ozone Levels Responses to Changes in Meteorological Conditions under RCP 4.5 and RCP 8.5 Scenarios over São Paulo, Brazil

Abstract

Since the implementation of emission control policies in 1983, the Metropolitan Area of São Paulo (MASP) has experienced a significant decrease in the annual mean concentration of air pollutants, except for ozone, which has remained relatively stable. This work analyzes the future impact on surface ozone formation in the MASP caused by changes in atmospheric conditions. The authors performed air quality simulations using the weather research and forecasting with chemistry (WRF-Chem) model under two representative concentration pathway (RCP) atmospheric conditions. A base case simulation from September and October 2018 was compared to scenarios for the same months in 2030, using the same anthropogenic emissions. Results show an average increase in peak ozone concentrations (0.43% for RCP 4.5 and 5.92% for RCP 8.5) with variations depending on the month and location. However, under the RCP 4.5 scenario, peak ozone concentrations in October were higher in urban areas than under the RCP 8.5. These outcomes can assist decision-makers in understanding the potential future impacts of high ozone formation, which has historically occurred in September and October in São Paulo by considering the effects of changing meteorological conditions, such as increased temperatures, higher surface radiation, and reduced cloudiness.