Air quality around schools: Part II - Mapping PM_2.5 concentrations and inequality analysis

Exposure to air pollution poses a significant risk to children's health. However, there is not currently a full and clear understanding of how many schools in England are in locations with high concentrations of air pollutants, and few studies have examined potential associations between air quality outside schools and socio-economic inequalities. To address these gaps, in this part of our study we used modelled air pollution concentrations, as well as monitoring data, to estimate how many schools in England are co-located with levels of annual mean PM_2.5 that exceed the WHO recommended annual mean limit of 10 μgm^-3, and matched school annual mean PM_2.5 concentrations to inequality metrics. We assessed the limitations of our methodology by carrying out a sensitivity analysis using a small patch of high-resolution air pollution data generated using a data extrapolation method. Mapping of modelled annual mean concentrations at school locations indicates that around 7800 schools in England - over a third of schools - are in areas where annual mean PM_2.5 in 2017 exceeded the WHO recommended guideline (10 μgm^-3). Currently over 3.3 million pupils are attending these schools. We also found that air pollution outside schools is likely to be compounding existing childhood socio-economic disadvantage. Schools in areas with high annual mean PM_2.5 levels (>12 μgm^-3) had a significantly higher median intake of pupils on free school meals (17.8%) compared to schools in low PM_2.5 areas (<6 μgm^-3 PM_2.5, 6.5% on free school meals). Schools in the highest PM_2.5 concentration range had significantly higher ethnic minority pupil proportion (78.3%) compared to schools in the lowest concentration range (6.8%). We also found that in major urban conurbations, ethnically diverse schools with high PM_2.5 concentrations are more likely to be near major roads, and less likely to be near significant greenspace, compared to less ethnically diverse schools in areas with lower PM_2.5 levels.