Mapping environmental inequalities and population exposure to air pollution, noise and greenness

Abstract Background Urbanization increases population exposure to environmental hazards, such as air pollution, traffic noise, and low access to greenery. Spatial and socio-economic segregation can amplify vulnerability, underscoring the need for population monitoring. The aim of this study was to map and analyze disparities in population exposure to air pollution (PM2.5, PM10 and NO2), traffic noise (road, rail and air) and low access to greenery in Stockholm County, Sweden. Methods We used sociodemographic data for 2,371,861 residents of Stockholm County (2019), obtained from Statistics Sweden (SCB) in a 100m x 100m grid. Air pollution was assessed by dispersion models, with high exposure defined as above the upper quartile (>5.9µg/m3; 8.8µg/m3; and 6.3µg/m3 for PM2.5, PM10 and NO2 respectively). We applied a 55dB LAeq,24h cut-off for modeled traffic noise and defined low access to greenery as a walking distance exceeding 200 meters from residence to the nearest green space. For analysis, we used a GIS tool that we developed based on ArcGIS Online and ArcGIS Pro 3.2.2 (Esri). Results The prevalence of high exposure to PM2.5, PM10 and NO2 was 57%, 61%, and 63%, respectively. In terms of high exposure to noise, road traffic accounted for the largest contribution (45%), clustering around major infrastructure corridors, in contrast to a minimal prevalence of 1% for air traffic, notably around airports, and 2% for rail traffic. Highly urbanized municipalities exhibited lower access to greenery (10% prevalence) compared to the rest of the county. Furthermore, we found distinct hot-spots of high exposure to multiple pollutants in the central highly urbanized part of the county. In the low-income population, 47% and 54% were highly exposed to air pollution and road traffic noise, respectively. Conclusions The overlapping exposures to multiple pollutants suggest population vulnerability to potentially compounding health risks, with increased susceptibility in low-income groups. Key messages • Mapping inequalities in population exposure to environmental hazards is of key importance for urban planning and prevention. • The results of this study will help regional planners to make informed decisions and steer targeted interventions for the reduction of negative public health impacts of environmental exposures.