By now, we have heard of at least some of the health effects of air pollution. The severe air pollution in Beijing has been associated with a reduction in life expectancy of up to 16 years, with women and young adults particularly susceptible. A recent article published online in JAMA Pediatrics demonstrates that particulate matter air pollution exposure during pregnancy is associated with shorter telomers at birth. This is a well-designed study that carries great significance because it demonstrates that air pollution may affect individuals from the beginning of life and have long lasting impactful effects on survival. The term “telomers” requires some explanation. Telomers are DNA sequences that occur at the end of chromosomes. They can initially be thousands of base-pairs in length and consist of repeated motifs of a six DNA base-pair sequence. Each time the cell divides, a portion of the telomer is lost, and so after repeated cell divisions, the length of the telomer shortens. Shorter telomers have been associated with mortality and diseases related to aging. They have also been associated with oxidative stress and inflammatory disease states. Telomers were discovered in 1984 by Elizabeth Blackburn and Carol Greider, who were awarded the 2009 Nobel Prize in Medicine and Physiology for this discovery. The study itself looked at prenatal exposure to air pollutants, in this case maternal residential PM2.5, which means particulate air pollution of average aerodynamic diameter of 2.5 microns (invisible to the naked eye), in 730 mothers from the Flanders region of Belgium, and found that newborns born to mothers with higher exposures had shorter telomers at birth. What does this mean? In other studies, telomer length has been associated with shorter life expectancy, and with various disease states including bone marrow failure, acquired aplastic anemia, cancer, liver disease and pulmonary fibrosis. Previous studies have found that telomer length is shorter in adults exposed to particulate air pollution. The fact that this study demonstrates that same finding in neonates born to mothers exposed to particulates suggests that the damage occurs early in life, before