Abstract: According to the São Paulo State Environmental Company (CETESB), in 2022, fixed and mobile sources were responsible for emitting approximately 4,500 tons of particulate matter (PM) into the atmosphere per year. Of this total, vehicles are responsible for 40% of PM. Monitoring air quality and air pollution is essential as it has an impact on human health. The eastern region of São Paulo has many socio-environmental problems, with a population density of 4.6 million inhabitants and 16 districts, terrain is largely sealed, high pollutant levels and few monitoring stations. In this scenario, low- cost Airbeam sensors have proved to be a good alternative for monitoring air quality in regions that do not have a high-cost reference network. Through them, a study was carried out monitoring fine particulate matter ((PM2.5) and relative humidity in 7 locations in the eastern zone of São Paulo, between April and October 2022, in order to verify the possible influence of land use and occupation on concentrations of the pollutant, especially green areas and roads with heavy vehicle traffic. The results showed that the average concentration of PM2.5 in the 7 locations was 10.3 μg/ m3, while the maximum concentration was 19.7 μg/m3 and the minimum concentration was 3.3 μg/m3. Site 1 is located on a busy, paved street corner and characterized by the presence of the little vegetation in the surrounding area. Here, the average concentration was 10.6 μg/m3, close to the overall average of the 7 sites, and its maximum average was 20.5 μg/m3, the second highest average. Its minimum average was 2.7 μg/m3, below the averages of the other sites. Site 2 is characterized by its proximity to a road with a heavy traffic volume, wich may explain why its average maximum concentration was 20.8 μg/m3, the highest among the 7 sites. Site 3 is characterized by an area with regular vehicle traffic and a few trees nearby but still had the highest average concentration (11.5 μg/m3) and also the highest minimum concentration (5.1 μg/m3). Site 4 is characterized by a narrow street with few trees nearby. Average concentration was similar to the average among the 7 sites of the 10.9 μg/m3. One of the explanations could be the large open area next to it, with dust resuspended from the ground. In addition, it had a minimum average concentration of 2.5 μg/m3, below the average of all the sites. Site 5 is characterized by low soil sealing and large green spaces, but close to roads with heavy vehicle traffic. At this location the average concentration was 11.0 μg/m3. Not only the average concentration, but also the maximum and minimum concentrations were within the average of the 7 sites sampled: 19.8 μg/m3 and 3.6 μg/m3, respectively. Site 6 had the lowest pollutant concentration results, with an average concentration of 9.7 μg/m3, a maximum concentration of 17.8 μg/m3 and a minimum concentration of 1.9 μg/m3. The area is residential, with low-rise building but few green areas. Site 7 is characterized by narrow street, the presence of small green areas and a cemented court on the surroundings. The average concentration was 11.3 μg/m3, higher than the average, while the maximum concentration was 19.1 μg/m3, lower than the average maximum concentration. It was observed that the standard recommended by the WHO for PM2.5 concentration (15 μg/m3) was exceeded in all the locations studied.

Keywords: PM2.5, São Paulo, low-cost sensors