Air Pollution Exposure Monitoring among Pregnant Women with and without Asthma.

: We monitored exposure to fine particulates (PM), ozone, nitrogen dioxide (NO), and ambient temperature for pregnant women with and without asthma. : Women ( = 40) from the Breathe-Well-Being, Environment, Lifestyle, and Lung Function Study (2015-2018) were enrolled during pregnancy and monitored for 2-4 days. Daily pollutants were measured using personal air monitors, indoor air monitors, and nearest Environmental Protection Agency's stationary monitors based on GPS tracking and home address. : Personal-monitor measurements of PM, ozone, and NO did not vary by asthma status but exposure profiles significantly differed by assessment methods. EPA stationary monitor-based methods appeared to underestimate PM and temperature exposure and overestimate ozone and NO exposure. Higher indoor-monitored PM exposures were associated with smoking and the use of gas appliances. The proportion of waking-time during which personal monitors were worn was ~56%. Lower compliance was associated with exercise, smoking, being around a smoker, and the use of a prescription drug. : Exposure did not vary by asthma status but was influenced by daily activities and assessment methods. Personal monitors may better capture exposures but non-compliance merits attention. Meanwhile, larger monitoring studies are warranted to further understand exposure profiles and the health effects of air pollution during pregnancy.