Secondhand smoke and secondhand aerosol The Impact of E Cigarettes and Asthma: What You Need to Know In the United States, about 8% of all women who are pregnant smoke cigarettes, and another roughly 4% report using electronic cigarettes or vapes. To learn more about the dangers of smoking Early life secondhand smoke exposure assessed by hair nicotine biomarker may reduce children's neurodevelopment at 2 years of age ScienceDirect