Breathing inequality: unmasking Liverpool's air pollution burden on deprived youth.

Liverpool, a city with an industrial legacy and among the most socioeconomically deprived local authorities in the UK, faces a significant health challenge: the combined impact of air pollution and deprivation on children's respiratory health. This study deploys a dense network of 52 air quality sensors, one of the most comprehensive in the UK, to monitor particulate matter in 2023. PM2.5 levels ranged from 4.78 to 18.15 µg/m (median 7.15 µg/m), and PM10 from 11.21 to 43.14 µg/m (median 17.30 µg/m), frequently exceeding WHO thresholds. High concentrations were found in northern wards with high deprivation. Hospital admission rates for under-18 s ranged from 0.2 to 2%, exceeding national averages. Linear regression showed Index of Multiple Deprivation (IMD) scores explained 16.1% of the variance in hospital admissions (R = 0.1608, β = 0.023 to 0.025, p < 0.02), more than PM2.5 (6.6%) or PM10 (4.7%). Interaction terms suggested amplified pollution effects in deprived areas. Liverpool offers a valuable case study for understanding the intersection of environmental and social determinants of health as seen in many urban UK settings. Socioeconomic deprivation emerged as both a mediator, through factors like healthcare access, and a confounder in the pollution-health relationship. These findings underscore the need for targeted emission reductions and investment in disadvantaged communities. Future research with extended data could confirm these patterns and support broader policy action.