The study presented a novel approach to understanding the associations between air pollution, fertilization, and embryo quality by evaluating the independent associations between maternal and paternal air pollution exposure at times when a female’s ovaries are producing eggs (also known as oocytes) and when a male’s testicles are producing sperm.

Ambient exposure to organic carbon—a major element of the hazardous fine particulate matter PM2.5, which is emitted from combustion sources such as vehicle exhaust, industrial processes, and wildfires—consistently showed negative impacts on oocyte survival, fertilization, and embryo quality.