Examining the role of greenspace to mitigate air pollution and motivate physical activity in four European cities

Exposure to urban greenspace may affect health via a complex set of pathways, including lessened exposures to air pollution and enhanced opportunity for physical activity. The HEALS study included personal monitoring of mothers of young children to pilot novel devices and collect environmental exposure data from individuals in four European cities. The data collected over ~1-week periods thus present an opportunity to assess these two important pathways for which greenspace may benefit health.We include three metrics of greenspace exposure (Normalised Difference Vegetation Index [NDVI], tree canopy density, and proximity to green land use) and will track objective measurements of physical activity through personal GPS data, including the duration engaging in active, e.g., walking, and passive, e.g., driving, transport. Fitbit units worn by study participants recorded steps per minute. Indoor PM2.5 and noise levels were collected from participants’ homes, and we are exploring the use of the Data Integration Model for Air Quality to estimate outdoor air pollutant concentrations.Based on the Edinburgh participants (n=29), preliminary results suggest no associations between residential greenspace metrics with indoor PM2.5, noise levels, or indicators of physical activity. However, using the GPS data, mean NDVI levels demonstrated significant positive correlations with the overall distance of walking or running (r=0.46; p=0.02) and also overall steps (r=0.41; p=0.04) during the monitoring period. No such associations were identified with tree canopy densities. We will expand the analysis to incorporate covariates of individual participants and data from the other cities to refine these early results.