Environmental Inequality and Child Health: Relationship Between Particulate Pollution and Cardiorespiratory Fitness in Southern Spain

Air pollution is one of the major environmental challenges threatening global sustainable development and human health. The World Health Organization identifies it as a critical factor contributing to non-communicable diseases and inequality, especially in vulnerable populations such as children. The findings highlight the negative effects of environmental degradation on physical health and underline the urgent need to incorporate health metrics, such as children’s fitness, into sustainability monitoring frameworks and public policies aiming at cleaner and healthier urban environments. The aim of this study was to examine the association between ambient particulate pollution and cardiorespiratory fitness in school-aged children from two rural villages in southern Spain characterised by relatively higher and lower levels of particulate matter. A total of 938 children (primary and secondary school levels) participated in a naturalistic pre–post study design. Cardiorespiratory fitness was assessed using the 6 min walk test, where maximal oxygen uptake (VO2max) was estimated. Assessments were conducted before and after a period characterised by unfavourable air-quality conditions in the higher-pollution village. The students were assigned by convenience into an experimental n = 476 (EG) and a control group n = 462 (CG). The t-test, repeated measures analysis and MANOVA test were used in order to report differences within and between groups, as well as time-points and academic levels. The significance level was set at p < 0.05. Significant differences between groups were reported within the pre-test period, showing elevated pre-test values in the CG compared to the EG. The EG showed a higher pre–post difference in estimated VO2max compared to the CG for primary education level (16.19%, ES(d) = 0.91 vs. 3.07%, ES(d) = 0.26; p < 0.001, respectively); secondary education (EG: 12.29%, ES = 0.91 vs. CG: 1.69, ES(d) = 0.16); and the whole population (EG: 14.72%, ES = 0.91 vs. CG: 2.84, ES = 0.25). It seems that the environmental context, and specifically the air pollution in the area of residence, may be an important factor to consider in relation to the assessment of physical fitness in the school-aged youth population.