Impacts of urban emissions and air quality in São Paulo State, Brazil

Daily violations of air quality have an impact on urban populations and cause damage to the environment. Thus, the study evaluated the violations of the daily concentrations of SO₂, NO₂, and PM₁₀, in regions of the State of São Paulo (SSP), based on the National Environment Council (CONAMA) resolution no 491/2018 and the World Health Organization (WHO - World Health Organization. (2016). Ambient air pollution: a global assessment of exposure and burden of disease.) criteria. Daily SO₂, NO₂, and PM₁₀data from 6 air quality stations operated by Environmental Company of the State of São Paulo CETESB (1996-2011) were organized and submitted to quality control, with data faults (gaps) being identified. The imputation of data via spline proved satisfactory in filling in the gaps (r > 0.7 and low values of Standard Error of the Estimate (SEE) and Root Mean Square Error (RMSE). The cluster analysis (CA) applied to SO₂ formed only one homogeneous group (G₁). Contrariwise, NO₂ and PM₁₀ formed two homogeneous groups (G₁ and G₂) each. The stations that showed the greatest similarity according to the CA were Cerqueira Cesar and Osasco. The cophenetic matrix generated for SO₂ (0.83), NO₂ (0.79), and PM₁₀ (0.77) indicate a satisfactory adjustment of the dendrograms. The exploratory statistics applied to groups G₁ and G₂ point to the high variability of outliers. The WHO criteria are more restrictive than CONAMA regarding daily violations, with a reduction in SO₂ and an increase in specific years for NO₂ and PM₁₀. Such variability is due to the adoption of public policies by the SSP and the influence of meteorological systems, being confirmed by the Run test that indicated oscillations in the time series, mainly in PM₁₀, and also recognized well-defined biannual cycles.