Dissertation Defense: Analysis of atmospheric pollutants MP10, NO2 and O3 in Salvador-BA and their relationships with meteorological factors

Air pollution has led to severe health problems for the population, ranking among the leading causes of death worldwide. In Brazil, although air quality monitoring is a responsibility of the states, few maintain monitoring networks and public data, with these networks being concentrated in the southeastern region. For the present study, it was possible to evaluate the air quality in the city of Salvador-BA, using data from eight automatic monitoring stations distributed throughout the city: Dique do Tororó (DT), Barros Reis (BR), Pirajá (PJ), Campo Grande (CG), Paralela (PR), Rio Vermelho (RV), Itaigara (ITG), and Av ACM (ACM), between 2014 and 2015. These stations measured concentrations of PM10, nitrogen dioxide (NO2), and ozone (O3), in addition to the monthly and hourly variations in concentration and the effects of meteorological variables, especially precipitation. The results showed that the annual average concentrations of PM10 and NO2 exceeded the values recommended by the World Health Organization (WHO), with PM10 at 25.5 ± 18.5 μm/m³ and 23.5 ± 13.9 μm/m³, and NO2 at 19.0 ± 10.2 and 22.1 ± 11.9 μm/m³, respectively, in 2014 and 2015. In contrast, O3 concentrations remained within the recommended limits, with the highest daily maximum 8-hour moving average of 45.7 μm/m³ at the DT station in 2014 and 53.8 μm/m³ at the PJ station in 2015. The BR station stood out among the others for having the highest number of days where PM10 concentration exceeded the recommended short-term (24h) value of 45 μm/m³ in 2014 and 2015, being the only station where the annual average was above the intermediate standard PI-1 of CONAMA 506 of 2024. The year 2014 had a rainfall index 17% below the climatological normal (1991-2020), while 2015 had 8% annual precipitation above the CN. It is noteworthy that no defined seasonal effect was observed for either PM10 or NO2, indicating that the effects of sources (e.g., sea breeze for PM10) are predominant throughout the year. However, higher concentrations of O3 were observed during the dry season at all monitoring stations, indicating the effect of clouds during rainfall on photochemical reactions.