A 2021 study, led by contributors from Stanford University, concluded that even brief childhood exposure to pollution could lead to major health problems in adulthood. Appearing in the journal Nature Scientific Reports, inhaling substances such as wildfire smoke and car exhaust over the span of just one day could lead to the later onset of heart disease.

The study focused its attention on a group of mainly Hispanic children between the ages of six and eight. These youths resided in Fresno, California, a city which has long struggled with consistently high levels of air pollution. Having chosen their city and subjects, the team set about measuring the levels of pollution floating through the air. To do this, the study authors relied on pollution readings collected from Fresno air monitoring stations, combining it with information from periodic spatial sampling and meteorological and geophysical data. Additionally, the study also relied on blood samples, blood pressure readings and demographic questionnaires to get a more complete picture of the children’s health.

If this research team is correct, air pollution exposure could be even more damaging than previously thought. Specifically, the report highlighted the impact of carbon monoxide, ozone and PM2.5 on DNA. Once inside the body, these pollutants altered the activity of DNA molecules, a development which could be passed down to the subject’s offspring. Furthermore, those routinely exposed to air pollution had higher levels of white blood cells called monocytes, which in excess can contribute to the buildup of arterial plaques. Elevated levels of monocytes may also increase risk of heart disease.