## 4 Discussion
An interesting aspect is that the maximum concentrations of PM\({}_{2.5}\) established by the WHO (annual concentration of 5 \(\upmu\)g/m\({}^{3}\) and 24-h concentration of 15 \(\upmu\)g/m\({}^{3}\)) and the national standard (annual concentration of 20 \(\upmu\)g/m\({}^{3}\) and 24-h concentration of 50 \(\upmu\)g/m\({}^{3}\)) show a significant difference in values, demonstrating that Chile far exceeds the established standards for both annual and daily concentrations. Related to this, in terms of morbidity, an average of 3007 hospitalizations for respiratory causes could have been avoided in people of all ages if Chile adhered to the WHO standard, and 1069 if it followed the national standard, which unfortunately is sometimes also not met [18]. Regarding AP, our results indicate that it is lower in more polluted areas across all SIMCE tests. This suggests a possible effect of PM\({}_{2.5}\) air pollution on student learning. In this context, [PERSON] et al. (2021) studied the impact of air pollution on AP in language and mathematics among children aged 5 to 16 in India. Their findings indicated that high levels of air pollution significantly reduce language and mathematics scores, and that this performance decline worsens with age [19]. As previously mentioned, prolonged exposure to PM\({}_{2.5}\) poses significant neurotoxic risks to children due to the ongoing development of their brains, particularly affecting the hippocampus and prefrontal cortex [20; 21], which may result in diminished short-term memory and impaired cognitive functions, such as mathematical reasoning and critical thinking [22]. Therefore, as the SIMCE test is based on the assessment of cognitive functions, these brain-level changes could be reflected in a decrease in AP. In this regard, schools located in areas with higher air pollution showed lower scores in mathematics, indicating reduced quantitative skills. Language were also negatively affected, possibly due to their reliance on cognitive skills related to memory and critical analysis, which may be more vulnerable to the neurotoxic effects of pollution [23]. The findings of this research are consistent with studies conducted in other areas of Chile, such as Puchuncavi and Quintero, known as \"sacrifice zones\", due to their high concentration of environmental pollutants. [PERSON] et al. (2024) demonstrate how exposure to heavy metals from industrial pollution and traffic is associated with lower AP. In these areas, a correlation has been found between increased levels of suspended elements such as arsenic, lead, and manganese, and decreased scores in AP tests like SIMCE among eighth-grade students [11]. This correlation highlights the importance of considering environmental factors when studying student performance in areas affected by pollution. On the other hand, it is interesting that no significant differences in SIMCE scores were observed between private and municipal schools when comparing institutions located in zones with higher versus lower air pollution. In this regard, it is possible that not only the level of PM\({}_{2.5}\) pollution is influencing the AP, but also other internal and/or external variables affecting the student. One of these variables that could partially explain these differences is the SES. In this regard, when analyzing this variable in subsidized private schools, we found that in the three most polluted areas, 67.5% have low and lower-middle SES, 21.5% middle, and 9.25% upper-middle and high SES. In contrast, in the three least polluted areas, the SES distribution was 2.5% lower-middle, 32.5% middle, and 65% upper-middle SES. These differences in terms of SES found in subsidized private schools are not present in private schools, both in more and less polluted areas, where 100% of them are in the upper-middle and high SES. In municipal schools in the most polluted areas, 14% are in the middle SES, 45% in the lower-middle SES, and 20% in the low SES.