Abstract: Objective To explore whether air pollution associates with the incidence of congenital heart disease(CHD).Methods We recruited 842 puerperae with infants of CHD and reporting their last menstrual period between January 1,2006 and December 31,2010 as the cases and randomly selected 914 puerperae with normal infants as the controls in Shenyang city.Then we conducted a questionnaire survey among the participants to collect information on their exposure to air pollutants before and during the pregnancy and analyze the relationship between the exposure and CHD incidence.Results Air pollution was heavy and there were significant differences in monthly concentrations of air pollutants in Shenyang city during the period between 2006 and 2010;the season with heavier air pollution was from November of a year to March of the next year,with the highest monthly concentrations of 145.9μg/m³ for sulfur dioxide(SO₂),541.4 μg/m³ for nitrogen dioxide (NO₂),and 163.6 μg/m³ for particulate matter<10 microns in aerodynamic diameter (PM10) and the lowest monthly concentrations of SO₂ (22 μg/m³),NO₂ (27.2μg/m³) in July,and PM10 (90.6 μg/m³)in August of a year.The cases reported significantly higher mean exposure to SO₂ and NO₂ during 2nd and 3rd month before the pregnancy and higher mean exposure to PM10 from the 1st to 3rd month before the pregnancy and of the gestation than those of the controls.Conclusion Pregnant women's exposure to high concentrations of airborne contaminants during the 3 months prior to conception and during early pregnancy may associate with the incidence of congenital heart disease in their offsprings.