Our objective was to study the association between gestational exposure to air pollutants during weeks 3–8 of pregnancy and the risk of congenital heart defects in an Israeli registry-based birth cohort from the Tel Aviv region between January 2000 and December 2006. The following pollutants were examined: nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), carbon monoxide (CO), particulate matter with aerodynamic diameter smaller than 10 μm (PM10) and
PM2.5 and.