According to a study published in the American Journal of Physiology — Lung Cellular and Molecular Physiology, pregnant mice that were exposed to air pollutants had an increased risk of asthma in their offspring for as many as three consecutive generations.
Researchers studied three generations of mice born to mothers that were exposed to either diesel exhaust particles or urban air particle concentrate during pregnancy. The research team compared cells from the lungs of the first, second and third generations of offspring to three generations of control offspring that were not exposed to the pollutants.
All generations descended from mothers exposed to diesel exhaust particles had an abnormal increase in a type of immune cell, a common marker for allergy. Offspring of pollutant-exposed ancestors also showed elevated levels of interleukin proteins that are involved in regulating the immune system, which are a marker of asthma risk.