Air pollution can harm the blood vessels of healthy young people, which helps explain why air pollution may trigger cardiovascular disease. Due to geographic conditions and other influences, Provo, Utah, periodically experiences relatively high levels of air pollution and was once ranked as one of the top 10 most polluted cities in the United States. Starting in 2013, researchers took blood samples for evaluation from 72 healthy adults in Provo for three consecutive winters, all of whom were nonsmokers and had an average age of 23 years at the time of participation in the study. The results of the blood sample analysis showed that whenever the concentration of fine particulate matter less than 2.5 microns in diameter (PM2.5) in the air increased, the blood samples of these young people also showed abnormal changes in the levels of cardiovascular disease markers. For example, blood samples showed a significant increase in the number of particles that indicate vascular cell injury and death, as well as an increase in levels of proteins that inhibit blood vessel growth and predict vascular inflammation. Aruni Bhatnagar, a professor at the University of Louisville who participated in the study, said the findings suggest that air pollution triggering high blood pressure, heart disease and stroke may be more common than previously thought, and occur at an earlier age than previously thought. While we already knew that air pollution could cause heart attacks or strokes in high-risk susceptible people,” Batnagar said, the findings show that air pollution can affect even seemingly healthy people as well, suggesting that air pollution should be a concern for all of us, not just the sick or elderly.