Phthalates are widely used in a large number of consumer goods and building materials from which they can leach and contaminate the environment such as indoor dust and air. It is unclear how phthalate sources in our homes and indoor dust contribute to human intake and airway symptoms in children. 

This thesis aims to contribute to the understanding of phthalate exposure by exploring connections between phthalate sources in home environments, indoor exposure, human intake, and childrens’ airway symptoms. It utilizes data in the Swedish SELMA study, including measurements of indoor dust phthalate levels and corresponding metabolites in prenatal maternal urine, and information on health outcomes and cofactors from self-administered questionnaires. 

The results show higher levels of three phthalates (DnBP, BBzP and DEHP) in dust from homes with PVC flooring. Four phthalates in dust (DEP, DnBP, DiBP, and BBzP) were positively correlated with corresponding maternal urinary metabolites. The dust was estimated to explain a 1-28% (median) contribution to the total daily intake of the analysed phthalates among pregnant women. Living in homes with PVC flooring was linked to a higher intake of BBzP and DEHP. Further, associations were found between prenatal phthalate exposure (BBzP, DiNP, DiDP and DPHP) and wheeze, and phthalates in dust (DEP, BBzP and DEHP) and croup in children before 2-years-of-age.

This thesis connects a full chain of factors relevant for human phthalate exposure. Sources in our homes were linked to higher levels in dust and to human intake. Also, both regulated and non-regulated phthalates were associated with human intake and airway symptoms. Combined with other research results, this implies that using new phthalates as replacements might not be optimal, and we could consider regulating phthalates as a group. Any links to effects in older children is unknown, still, limiting indoor phthalate sources could reduce intake and benefit overall public health.

The indoor environment is important for our health; still, a mix of phthalates, that are either non-regulated or classed as hazardous, can be detected in dust in our homes. The phthalates have leached from various products and building materials such as plastics, electronics, perfume, and interiors. Should this make us concerned?

This thesis has followed indoor phthalate exposure from vinyl (PVC) flooring materials to dust, to phthalate intake among pregnant women, and finally to investigated if airway symptoms in young children are linked to either phthalate exposure of the fetus or phthalates in bedroom dust.

The results show that phthalates from vinyl floorings can be followed through this full exposure chain. Both regulated and non-regulated replacement phthalates were associated with human intake and airway symptoms in children. Combined with other research results, this implies that using new phthalates as replacements might not be optimal, and we could consider regulating phthalates as a group. Although the risk is relatively low for the individual, reducing phthalate sources and exposure during early human development may have benefits on a public health level and contribute to more sustainable use of resources.