Spatial variability of nitrogen dioxide and formaldehyde and residential exposure of children in the industrial area of Viadana, Northern Italy

Chipboard production is a source of ambient air pollution. We assessed the spatial variability of outdoor pollutants and residential exposure of children living in proximity to the largest chipboard industry in Italy, and evaluated the reliability of exposure estimates obtained from a number of available models. We obtained passive sampling data on NO2 and formaldehyde collected by the environmental protection agency of Lombardia region at 25 sites in the municipality of Viadana during 10 weeks (2017-18), and compared NO2 measurements with average weekly concentrations from continuous monitors. We compared interpolated NO2 and formaldehyde surfaces with previous maps for 2010. We assessed the relationship between residential proximity to the industry and pollutant exposures assigned using these maps, as well as other available countrywide/continental models based on routine data on NO2, PM10, and PM2.5. The correlation between NO2 concentrations from continuous and passive sampling was high (Pearson’s r=0.89), although passive sampling underestimated NO2 especially during winter. For both 2010 and 2017-18, we observed higher NO2 and formaldehyde concentrations in the south of Viadana, with hot-spots in proximity to the industry. PM10 and PM2.5 exposures were higher for children at <1km compared to the children living at >3.5 km to the industry, whereas NO2 exposure was higher at 1-1.7 km to the industry. Road and population densities were also higher close to the industry. Findings from a variety of exposure models suggest that children living in proximity to the chipboard industry in Viadana are more exposed to air pollution, and that exposure gradients are relatively stable over time.