The World Health Organization (WHO) established in 2021 an annual health limit of 5μg/m3 for outdoor PM2.5 concentrations (cPM2.5). Our objective was to evaluate the health impact of cPM2.5 in two locations of a large city during 2023. In the first study (South; more socially vulnerable), the 5μg/m3 limit was exceeded 70% of the time. Additionally, 26% of the values were above 15μg/m3. In the second study (Central), this limit (5μg/m3) was exceeded 99% of the time, and 64% of the values were above 15μg/m3. Based on data from both locations (1,149,930 inhabitants over the age of 25), annual lung cancer mortality ranged from 23 to 38 cases (6.7%–8.7%), while mortality from non-communicable diseases ranged from 700 to 854 cases (10.7%–12.3%). The avoidable burden of mortality attributable to annual PM2.5 concentrations justifies the urgent need for their drastic reduction as a public health policy.
