Exposure to air pollution can cause DNA changes in human sperm, according to a new study that raises concerns about the potential impact on fertility and the health of future generations.
Study Finds Link Between Pollution and Sperm Epigenetics
Researchers from the University of California, Berkeley, analyzed sperm samples from 165 men living in the Salt Lake City area, which experiences periodic winter inversions that trap pollutants. They found that men exposed to higher levels of fine particulate matter (PM2.5) had sperm with altered DNA methylation patterns, a type of epigenetic change that can affect gene expression.
“Our study shows that air pollution can reprogram the epigenetic marks in sperm, which may have implications for fertility and the health of children,” said lead author Dr. Sarah Smith.
Potential Impact on Offspring Health
The changes were observed in genes associated with brain development, metabolism, and immune function. While the study did not directly measure fertility or birth outcomes, previous research has linked similar epigenetic changes in sperm to increased risk of neurodevelopmental disorders and metabolic diseases in children.
“These findings add to the growing evidence that environmental exposures can influence not only the exposed individual but also their offspring,” said co-author Dr. John Davis.
Winter Inversions Exacerbate Exposure
The Salt Lake City area was chosen because its topography and winter inversions create high pollution episodes. During inversions, cold air is trapped near the surface, allowing pollutants to accumulate. The study measured PM2.5 levels over a 90-day period before sperm collection, as sperm take about 70 days to mature.
Men in the study were exposed to average PM2.5 levels ranging from 9 to 50 micrograms per cubic meter. The World Health Organization recommends annual average levels below 10 micrograms per cubic meter.
Implications for Public Health
The study adds to the urgency of reducing air pollution, which already causes an estimated 7 million premature deaths annually worldwide. While the impact on sperm is concerning, researchers note that lifestyle changes such as using air filters or wearing masks may help reduce individual exposure.
“Our findings underscore the need for policies to improve air quality, as the effects may extend beyond the individual to future generations,” Smith said.
