Assessing the Impact of Exposure to PM\({}_{2.5}\) Air Pollution on the Academic Performance of Schoolchildren in Chile  
[PERSON]  
1 Escuela de Kinesilologia, Pontificia Universidad Catolica de Valparaiso, Avenida Universidad 330, Valparaiso 2373223, Chile; [EMAIL_ADDRESS] (F.-H.); [PERSON](C.C.-N.); [EMAIL_ADDRESS] (J.G.-S.); [EMAIL_ADDRESS] (M.-P.T. ); [EMAIL_ADDRESS] (E.V.-Z. ); [PERSON] (O.A. ); [EMAIL_ADDRESS] (G.-G.); [EMAIL_ADDRESS] (J.-N.); [PERSON]] (O.A. ); [EMAIL_ADDRESS] (F.G.-G.)  
As in other cities in developing countries, air pollution in Chile is prevalent in areas with a high concentration of industries, heavy vehicular traffic, and widespread use of wood-burning heating [3]. Despite existing regulations, pollution persists in some areas, producing significant environmental and health impacts for local communities. To date, environmental pollution control measures have been implemented in Chile, leading to a progressive improvement in air quality; however, these efforts remain insufficient. Air pollution is closely associated with atmospheric particulate matter (PM), PM\({}_{2.5}\) refers to fine particulate matter with an aerodynamic diameter \(\leq\) 2.5 \(\upmu\)m, capable of penetrating deep into the respiratory system and crossing the blood-brain barrier, posing significant health risks, particularly to children. PM\({}_{10}\), or coarse particulate matter with a diameter \(\leq\) 10 \(\upmu\)m, primarily affects the up-per respiratory tract but is less likely to reach systemic circulation. This study focuses exclusively on PM\({}_{2.5}\) due to its established neurotoxic effects and relevance to cognitive development [1]  
The main components of PM\({}_{2.5}\) include sulfates, nitrates, ammonium, organic carbon, elemental carbon, and mineral dust, with metals (e.g., copper, lead) and polycyclic aromatic hydrocarbons (PAHs) present in smaller proportions. Regarding size, PM\({}_{10}\) and PM\({}_{2.5}\) have aerodynamic diameters of 10 \(\upmu\)m and 2.5 \(\upmu\)m and are referred to as coarse and fine particles, respectively. PM\({}_{2.5}\) has been observed to contain organic and inorganic components from various anthropogenic sources, such as copper (Cu) and high-molecular-weight polycyclic aromatic hydrocarbons (PAHs), which are generated from the incomplete combustion of fossil fuels, among others [1]. The relevance of PM\({}_{2.5}\) lies in the fact that the pollutants it contains have been identified as toxic, especially for development in children [4]. Children are particularly vulnerable to air pollution due to their developing respiratory and immune systems, lower body mass, and specific breathing patterns, which increase pollutant absorption [5; 6]. Air quality in schools is an emerging concern, potentially posing even greater health risks than outdoor pollution [7]. Exposure during this critical developmental stage can negatively affect children's respiratory, cardiovascular, and cognitive systems [8; 9], with studies reporting lower neurobehavioral and IQ test scores, as well as neurological impairments, among exposed children [3; 10; 11]. PM\({}_{2.5}\) can penetrate deep into the lungs, enter systemic circulation, and cross the blood-brain barrier, producing neurotoxic effects during childhood [12; 13]. Chronic exposure has been associated with neuroinflammation and oxidative stress, particularly in the hippocampus and prefrontal cortex--regions critical for memory and learning [14; 15; 16]. Both human and animal studies have shown that PM\({}_{2.5}\) exposure alters neuronal function and morphology through mechanisms like microglial activation and disrupted metabolism in key brain areas [17; 18; 19]. Persistent neuroinflammation and disruption of neuronal homeostasis due to PM\({}_{2.5}\) exposure can impair synaptic circuits, negatively impacting cognitive abilities such as working memory, reasoning, and concentration--key skills for academic performance.