Does Reduced Outdoor Activity Due to Fine Particulate Matter Negatively Affect Children's Depressive Symptoms?

Background:

Exposure to air pollution has detrimental effects on human health and past studies have found that exposure to fine particulates, also known as fine dust, can cause adverse health outcomes, such as lung cancer and mortality. Thus, many governments measure the level of fine particulates daily and discourage people from going outside if the levels are high. Although reducing outdoor activities might be one way to decrease the exposure to fine particulates and prevent health risks, discouraging outdoor activities due to fine particulate matter may negatively affect mental health outcomes because of the past evidence suggesting significant associations between reduced physical activity and adverse mental health outcomes. Since children tend to have a high desire for physical activities, discouraging outdoor activities due to fine particulate matter may lead to negative mental health outcomes for children by increasing their stress level.

Thus, this study examines: 1) whether higher exposure to fine particulates is associated with children’s depressive symptoms, and 2) whether reduced physical activity partially explains the association between fine particulate exposure and children’s depressive symptoms.

Method:

This study uses fine particulate data from Air Korea and children’s data from the Time Use Survey collected by the Child Fund in Korea. The sample are 4,490 children in 2018. The children’s depressive symptoms is measured by the Child Behavior Checklist. Physical activity is measured by the total number of minutes that children spent on sports and leisure in weekdays. Exposure to fine particulate matter is measured by averaging the levels of particles with an aerodynamic diameter ≤2.5 μm. Multi-level regression and multi-level structural equation models are used to examine the associations between exposure to fine particulates, physical activity, and children’s depressive symptoms.

Results:

Our findings suggest that although the exposure to fine particulate matter are not directly associated with children’s depressive symptoms, reduced physical activity partially mediate the association between fine particulate matter and children’s depressive symptoms. Exposure to fine particulate matter is negatively associated with physical activity, which then increases children’s depressive symptoms.

Conclusions:

Our findings highlight the importance of outdoor activity in relation to children’s depressive symptoms. Because exposure to fine particulate matter is associated with children’s depressive symptoms partially due to reduced physical activity, governmental recommendations discouraging outdoor activities may not be the best solution to reduce health risks due to the fine particulate matter. Encouraging physical activity for children, even in the presence of severe fine particulates, may be beneficial for promoting the mental health outcomes of children.