Photo: Laura Guerrero / Barcelona City Council Early-life exposure to air pollution, urban environments, natural spaces, and breastfeeding may influence the timing of puberty, according to new research. [This article was co-authored by Marta Pinto da Costa and Augusto Anguita-Ruiz, Junior Research Leader at ISGlobal.] Reading time: 4 minutes Over the past decades, a worldwide declining tendency in the age at menarche and the onset of puberty has been observed.