Abstract: The city of São Paulo faces significant challenges related to air pollution, particularly the concentration of particulate matter. This problem is driven by factors such as intense industrial activity, increased vehicular traffic and unfavorable weather conditions. Particulate matter from a variety of sources, including the burning of fossil fuel, has a direct impact on air quality and public health. Particulate matter, especially fine particles (PM2.5), pose serious health risks to the population, penetrate deep into the lungs and even enter the bloodstream. Adverse effects include the worsening of pre-existing respiratory diseases, such as asthma and bronchitis, as well as an increase in cases of cardiovascular disease.Vulnerable groups such as children, the elderly and people with pre-existing medical conditions are the most affected. This study aims to correlate PM2.5, PM10 and Black Carbon (BC) concentrations between the years 2021 and 2022, comparing the periods with and without restrictions caused by the COVID-19 pandemic. The equipment (Partisol 2025i and Aethalometer AE33) remained on an important avenue with intense vehicular flow in the central region of the city of São Paulo. Daily and hourly data were analyzed using the openair package, available in the R software. Following the new WHO guidelines, the preliminary results showed exceedances in PM2.5 and PM10 concentrations during the dry season (June to August). In total there were 32 and 24 days of exceedances, representing 4.4% and 3.3% of the total period sampled for PM2.5 and PM10, respectively. With regard to BC, the highest concentrations occurred in June to July and 2021 and May to August in 2022, coinciding with the highest PM concentrations. During the restriction period from March to September 2021 the average concentrations were below 50 μg/m3 (PM2.5) and 100 μg/m3 (PM10) of that observed for the same period in 2022. The contrast between the periods restricted by the pandemic highlights the influence of vehicular sources, underscoring the importance of integrated approaches to mitigating the impacts of air pollution.

Keywords: Particulate matter, black carbon, vehicle source, COVID-19.