Prenatal exposure to air pollution is considered to be associated with adverse effects on developmental processes and children’s health. This may partly be mediated by mechanisms related to DNA methylation. The aim of this study is to investigate the relationship between in utero exposure to air pollution (specifically fine particulate matter ≤10μm (PM10)) with DNA methylation at over 480,000 methylation CpG sites across the genome. This project will work in concert with preliminary analysis conducted by the PACE consortium (Pregnancy and childhood epigenetics), a large collection of birth cohort studies, that have identified several putative CpG-air pollution associations that need to be replicated in a separate, independent study. At the time of the initial conception of this project within PACE, ALSPAC did not have the air pollution data required to participate. However, this has since been developed and we will seek to use the ALSPAC consortium as a unique resource to examine association between PM10 and DNA Methylation at birth, verifying the preliminary results of the PACE analysis.