A new medical study conducted in the United States has identified air pollution as a significant potential contributor to male infertility, providing fresh insight into how polluted air may damage reproductive health at the genetic level.
Researchers from the University of Massachusetts found that exposure to air pollution can switch off genes responsible for producing healthy sperm, potentially increasing the risk of infertility among men. The findings help explain why previous studies consistently reported higher infertility rates among men living in heavily polluted areas, although the underlying biological mechanism had remained unclear.
According to the researchers, air pollution causes chemical changes in DNA through a process known as epigenetic modification. Rather than altering the genetic code itself, these changes act like a light switch, turning important fertility-related genes on or off. When these genes are switched off, the body’s ability to produce healthy sperm may be significantly impaired.
The study examined more than 2,000 men over a six-month period, monitoring their reproductive health alongside changes occurring in their DNA. Researchers specifically analyzed the effects of common air pollutants, including ozone, nitrogen dioxide, sulfur dioxide, and fine particulate matter.
The results showed that prolonged exposure to these pollutants was associated with 39 distinct DNA changes linked to impaired sperm production and a higher likelihood of infertility.
“Our findings suggest that air pollution affects male reproductive health by altering DNA in ways that interfere with sperm development,” the researchers noted. They added that the study is an important step toward understanding the biological pathways through which environmental pollution may contribute to infertility.
The research has been published in the peer-reviewed journal Human Reproduction.
Scientists have long suspected that environmental chemicals play a role in declining fertility, but direct evidence explaining how pollution influences reproductive function has been limited. This latest study strengthens the scientific understanding of the relationship between environmental exposure and male fertility.
The findings build upon previous research published in the British Medical Journal in September 2024, which also linked exposure to fine particulate air pollution with an increased risk of infertility in men.
That earlier study analyzed health data from more than 526,000 men aged 30 to 45 and over 377,000 women. Researchers compared fertility outcomes with long-term exposure to air pollution and traffic noise between 1995 and 2017.
During that period, infertility was diagnosed in 16,172 men and 22,672 women.
After accounting for factors such as income, education, occupation, and other lifestyle variables, researchers found that men exposed to higher concentrations of fine air pollution particles for five years had a 24 percent greater risk of infertility compared with those living in cleaner environments.
Interestingly, the study found that air pollution did not significantly increase infertility risk among women. However, prolonged exposure to traffic noise averaging 10.2 decibels above baseline levels was associated with a 14 percent higher risk of infertility in women aged 35 and older over a five-year period.
Traffic noise, however, showed no significant effect on male reproductive health, while younger women also did not appear to experience increased infertility risk from noise exposure.
The World Health Organization (WHO) has also highlighted infertility as a growing global public health concern.
In a report published in April 2023, the WHO estimated that approximately 17.5 percent of the world’s adult population experiences infertility at some point during their lives. The estimate was based on more than 100 scientific studies conducted between 1990 and 2021.
The organization found that infertility affects people across all income levels and regions. The prevalence was estimated at 17.8 percent in high-income countries and 16.5 percent in low- and middle-income countries, indicating that infertility is a worldwide health challenge rather than one limited to specific populations.
Previous research has also shown that male factors contribute to approximately one-third of infertility cases among couples, emphasizing the importance of understanding environmental and biological influences on men’s reproductive health.
Experts say the new findings reinforce the need for stronger environmental protections and public health measures aimed at reducing exposure to harmful air pollutants. While lifestyle factors such as smoking, alcohol consumption, obesity, poor diet, and certain medical conditions are known to affect fertility, environmental pollution may represent another significant but often overlooked risk factor.
Despite the promising findings, researchers caution that the study remains observational. Although strong associations were identified between air pollution, DNA changes, and infertility risk, additional research is needed to establish a direct cause-and-effect relationship and determine whether reducing pollution exposure can reverse or prevent these genetic changes.
Scientists hope future studies will investigate whether protective interventions, cleaner air policies, or medical treatments can reduce the reproductive effects of pollution.
As air quality continues to decline in many urban centers worldwide, the latest research adds to growing evidence that environmental pollution may have consequences extending well beyond respiratory and cardiovascular health, potentially affecting future fertility and reproductive outcomes as well.
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