Combined exposure to urban green and blue spaces may reduce the risk for emotional and behavior problems among youthResearch indicates that exposure to green space (GS) and blue space (BS) are linked to beneficial health and mental health outcomes for urban residents. However, the existing literature has mainly considered coastal BS exposure and older adult populations, while younger populations and inland blue spaces (BSs), such as rivers, lakes, and wetlands, have received far less attention in mental health research. Further, the majority of studies have also only examined the individual effects of GS or BS and have not considered the potential combined effect of GS and BS on human health. This large-scale epidemiological study, therefore, aimed to deepen understanding of children’s and adolescent’s combined exposure to both green and blue spaces (GBS). The study utilized population-based survey data to examine the prevalence of emotional and behavioral problems (EBPs) among children and adolescents in relation to their GS and BS exposures. The study then examined the relationship between combined GBS exposure and youths’ emotional and behavioral problems (EBPs).
The study utilized data collected from 172,490 urban children and adolescents (ages 6-18 years) in Guangzhou city, China. The majority of participants were boys (55.8%), and the average age of participants was 10.2 years. Land-cover map databases were used to determine each participant’s school and home neighborhood GBS exposure at 500- and 800-meter circular buffer distances. Daily GBS exposure rates were calculated based on estimated time spent at school and at home. Participants were grouped into three tertiles of GBS exposure levels, with the first tertile having the lowest exposure and the third tertile having the highest exposure. The Strengths and Difficulties Questionnaire (SDQ) was used to assess EBPs, which consisted of five subscales for emotional symptoms, conduct problems, hyperactivity/inattention, peer relationship problems, and prosocial behaviors. The questionnaires were completed by children’s/adolescents’ parents, who rated their child’s behaviors over the previous six months. Questionnaire responses were calculated to determine a total difficulties (TD) score for each participant. Data was also collected for a variety of factors that could potentially influence the relationship between GBS and EBPs. These included participant age, gender, weight, parent education level, household income, outdoor physical activity time, and screen time. Statistical analyses examined if participant’s level of exposure to GS, BS, and GBS was related to their reported EBPs.
Preliminary analysis revealed that participants with TD scores that were indicative of EBPs tended to report less physical activity and higher screen times compared to participants who were not at risk of EBPs. Results of the main analysis indicated that participants who were exposed to higher levels of GS around their home or school had significantly lower rates of EBPs compared to those who had less GS exposure at both 500- and 800-meter buffer distances. Likewise, participants with higher levels of BS exposure around home or school were significantly less likely to have EBPs compared to those with low levels of exposure to BS. Analysis that examined participants’ combined exposure to GBS found that participants with higher exposures (regardless of buffer distance) were at a significantly lower risk of EBPs. In fact, compared to participants with low levels of GBS exposure, risk of EBPs was reduced by 9.3% for participants with higher home exposure and 8.5% for participants with higher school exposure. Examination of individual SDQ subscales found that higher GS exposure was strongly related to reduced emotional symptoms, while higher BS exposure was strongly related to reduced conduct problems. However, neither GS nor BS exposure were significantly related to peer relationship problems. Finally, analysis revealed that the relationship between GBS and reduced EBPs was stronger for participants with higher physical activity levels.
As the first large-scale investigation of the relationship between GS, BS, and EBP, the study contributes important insights to the benefits of children’s exposure to natural environments. Findings revealed a consistent pattern in which “living in close proximity to greenspace and water areas, and having more exposure to GS and BS coverage, resulted in improved emotional and behavioral health among youths.” Although the mechanisms within this relationship are not fully understood, the study provides some indication that increased physical activity may play an important role. Importantly, findings also indicate that an additional interaction effect between GS and BS may help to reduce the risk of EBP. Therefore, “a higher level of GBS within a neighborhood, in conjunction with an integrated effect arising from both exposures (GS and BS),” may support enhanced emotional and behavioral wellness for youth.
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