Introduction - Indoor air quality is a major public health concern due to the amount of time spent indoors and the variety of sources of pollutants. The objectives of this study are to: document indoor concentrations of chemical pollutants; model annual household exposure to chemical pollutants; and quantify the associations between estimated household levels and children’s respiratory health during their first year of life. Materials and Methods - Based on repeated measurements taken in a random sample of newborns from the Paris cohort, predictive models of annual concentrations of formaldehyde, toluene, and nitrogen dioxide (NO₂) were constructed and applied to all housing units to estimate the exposure of children in the cohort and to study its association with lower respiratory tract infections and nocturnal dry cough. Results - The predictive models identified the determinants of annual concentrations of formaldehyde, toluene, and NO₂: continuous sources and recent sources (particleboard, varnished hardwood flooring, laminate flooring, floating flooring, paint), intermittent sources (combustion), and ventilation and confinement parameters. After adjusting for all confounding factors, only formaldehyde exposure was associated with the occurrence of lower respiratory tract infections (wheezing) and nocturnal dry cough, particularly in children without a parental history of allergy. Conclusion - Domestic exposure to indoor air pollutants, such as formaldehyde, is associated with respiratory morbidity in infants. These results support the measures taken by public authorities regarding emissions from building materials.