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 NO and formaldehyde collected by the Environmental Protection Agency of Lombardy region at 25 sites in the municipality of Viadana during 10 weeks (2017-2018) and compared NO measurements with average weekly concentrations from continuous monitors. We compared interpolated NO 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 NO, PM, and PM. The correlation between NO concentrations from continuous and passive sampling was high (Pearson's r = 0.89), although passive sampling underestimated NO especially during winter. For both 2010 and 2017-2018, we observed higher NO and formaldehyde concentrations in the south of Viadana, with hot-spots in proximity to the industry. PM and PM exposures were higher for children at < 1 km compared to the children living at > 3.5 km to the industry, whereas NO 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.