There is a great and growing interest in the effects of environmental exposures, both among the general population and among health professionals. Among the exposures that have the greatest impact on health is air pollution. Specifically, very small particles (such as PM2.5, which are one millionth of a meter in diameter in micrometers) enter the body through the respiratory system and the olfactory system, and affect all human organs. We are increasingly aware of these effects, especially their impact on the central nervous system and neurodevelopment, especially during pregnancy and childhood. Indeed, childhood exposures indicate that they cause changes in basic neuropsychological functions, such as memory and attention, but more evidence is needed to support the adoption of measures that help reduce this exposure, especially for the most vulnerable population, such as pregnant women and children, as well as groups in the most disadvantaged socio-economic and environmental situations.

This study examined the relationship between exposure to small particles (micrograms/cubic meter of air) in the air around children's homes and their impact on fine motor functions (finger and hand movements) and gross motor functions (movements involving the body), as well as on two basic psychological functions: memory and attention, using standardized and validated tests. To calculate the exposure levels of each child, real data obtained with equipment that allows the capture of pollutants in the atmosphere are used, and for this purpose, complex models are used to assign pollutant levels at different points in space and at different times. Thus, exposure to PM2.5 was measured during the prenatal period (pregnancy) and childhood. In addition, motor and psychological functions were assessed by neuropsychologists at the age of 6 in 1310 children from all subcohorts of the INMA (Childhood and the Environment) project. With these data, the research team aimed to identify periods that could be sensitive to PM2.5 exposure, both in the prenatal phase and in childhood.

As the researchers acknowledge, “the results were suggestive rather than conclusive.” On the one hand, they found a negative association between PM2.5 pollution and attention, in relation to pollution during pregnancy. On the other hand, they also found a negative relationship with memory, in this case with exposure to pollution during childhood. However, the results did not show sufficient robustness and should be evaluated with caution.

Although the impact of such studies does not directly affect patients, when studying the general population, they are useful for having evidence to establish effective preventive measures, that is, to prevent or minimize the onset of diseases. In fact, potential risk factors are studied, and they must be confirmed in the general population or in a specific group of that population, at what levels (high or low) they affect it, or whether these effects depend on the characteristics of the social context or the phenomenon itself that we are studying.

“With such studies, we hope to help the relevant administrations to take measures regarding atmospheric pollution, as well as to help raise public awareness, in order to reduce the effects of this major environmental pollutant on various diseases and the mortality associated with these diseases,” stated the research team.

The INMA (Childhood and the Environment) project is being carried out with the participation of mothers and children/adolescents from 6 sub-cohorts: Granada, Menorca, Asturias, Valencia, Sabadell and the Gipuzkoa sub-cohort. The project has lasted 20 years and has been funded by: the municipalities of the study area (Goierri, Urola Garaia and Erdi Urola), the Health Departments of the Autonomous Communities (including the Public Health Directorate of the Basque Government's Health Department), the Provincial Council of Gipuzkoa, the Carlos III Health Institute and several European projects. Many health professionals from hospitals or health centers have also participated. In addition, this study is led by researchers from Baylor University (Houston, Texas) and funded by the US National Institutes of Health.

Finally, the research team thanks “the families who participated in the study and, especially, the mothers who participated and the children in this project who are now adolescents, for their generous support.”