The spatial-temporal effect of air pollution on individuals’ reported health and its variation by ethnic groups in the United Kingdom: A multilevel longitudinal analysis

Background Air pollution is associated with poor health; though it is unclear whether this association is stronger for ethnic minorities compared to the rest of the population. This study uses longitudinal data to investigate the spatial–temporal effect of air pollution on individuals’ reported health and its variation by ethnicity in the United-Kingdom (UK). Methods Longitudinal individual-level data from Understanding Society: the UK Household Longitudinal Study including 67,982 adult individuals with 404,264 repeated responses over 11 years (2009–2019) were utilized and were linked to yearly concentrations of NO2, SO2, and particulate-matter (PM10, PM2.5) pollution once at the local authority and once at the census Lower Super Output Area (LSOA) of residence for each individual. This allows for analysis at two geographical scales over time. The association between air pollution and individuals’ health (Likert scale: 1–5, Excellent to poor) and its variation by ethnicity was assessed using three-level mixed-effects ordered logistic models. Analysis distinguished between spatial (between areas) and temporal (across time within each area) effects of air pollution on health. Results Higher concentrations of NO2, SO2, PM10, and PM2.5 pollution were associated with poorer health. Decomposing air pollution into between (spatial: across local authorities or LSOAs) and within (temporal: across years within each local authority or LSOA) effects showed a significant between effect for NO2 and SO2 pollutants at both geographical scales, while a significant between effect for PM10 and PM2.5 was shown only at the LSOAs level. No significant within effects were detected at an either geographical level. Indian, Pakistani/Bangladeshi, Black/African/Caribbean and other ethnic groups and non-UK-born individuals reported poorer health with increasing concentrations of NO2, SO2, PM10, and PM2.5 pollutants in comparison to the British-white and UK-born individuals. Conclusion Using longitudinal data on individuals’ health linked with air pollution data at two geographical scales (local authorities and LSOAs), this study supports the presence of a spatial–temporal association between air pollution and poor self-reported health, which is stronger for ethnic minorities and foreign-born individuals in the UK, partly explained by location-specific differences. Air pollution mitigation is necessary to improve individuals’ health, especially for ethnic minorities who are affected the most.