Infertility is a growing global concern, affecting millions. Beyond age, lifestyle, and medical conditions, new research is highlighting the alarming role that environmental pollutants like air and noise pollution can have on fertility.

Two studies from Denmark and the United States now provide compelling evidence of these risks. They show how everyday pollutants seriously impair reproductive outcomes.

A Danish nationwide cohort study tracked over 900,000 adults between 2000 and 2017, examining the impact of road traffic noise and particulate air pollution (PM2.5) on fertility. PM2.5 is a type of fine particulate matter with a diameter of 2.5 micrometers or smaller, which is a harmful air pollutant that can penetrate deep into the lungs and enter the bloodstream, posing significant health risks.

Researchers found that long-term exposure to PM2.5 increased infertility risk in men. Each 2.9 µg/m³ rise in exposure over five years was correlated to a 24% higher risk of infertility among men aged 30-45. For reference, the average PM2.5 pollution in New York City is currently 4.2µg/m³, while in London it’s 9.8µg/m³. In Shanghai, it’s over 100µg/m³.

In women, road traffic noise posed a significant risk, particularly for those aged 35-45. For every 10.2 decibels (dB) increase in average noise exposure over five years, infertility risk increased by 14%. A quiet rural area has around 30 dB while a suburb has around 40 dB.

The effect was more pronounced among women with primary infertility, but curiously, PM2.5 was not associated with infertility in women.

While the findings may seem striking, previous studies highlighted similar things, linking air pollution to reduced fertility. A 2017 study found that all sorts of air pollutants lead to “a drop in reproductive capacities in exposed populations” and that air quality has an impact on “overall health as well as on the reproductive function.” In fact, a previous study found a link between air pollution and female fertility as well, though judging by this study, it’s not PM2.5, but other types of pollution.

Air Pollution’s Impact on IVF Success

Complementing the Danish research, a US study focused on individuals undergoing in vitro fertilization (IVF) provided an in-depth look at how air pollution disrupts egg, sperm, and embryo development. The study analyzed 1,400 participants, and because of the nature of the study (participants had donated their eggs and sperm), researchers could track the development of reproductive cells in detail.

They found that exposure to particulate matter and organic carbon (pollutants common in vehicle emissions and industrial processes) significantly impaired oocyte survival, fertilization, and embryo quality. The study also confirmed that paternal factors are also affected by pollution.

Even brief exposure during sensitive phases (like ovarian stimulation and spermatogenesis) had measurable impacts, emphasizing the importance of reducing air pollution during these critical windows.

Together, these studies do a great job of showcasing the impact that pollution has on infertility. While the Danish research pinpointed PM2.5 as a major risk factor for infertility on a large scale, the US study added depth by demonstrating its effects on both egg and sperm quality. Meanwhile, the stress-inducing effects of noise pollution appeared particularly detrimental to women.

Where the pollution comes from — and what to do against it

The research shows that particulate matter, a pervasive pollutant from diesel vehicles, power plants, and wildfires, plays an important role in the global infertility crisis. Findings from both studies underscore the need for stricter environmental regulations, particularly regarding air quality standards and urban noise control.

Until that happens, a good place to start would be avoiding high-traffic areas and staying indoors on days with poor air quality. For those in noisy urban environments, creating quieter sleeping spaces may help mitigate stress and improve overall health.

It’s not just outdoor pollution; oftentimes, indoor pollution is just as nefarious, or even more. Researchers recommend enhancing indoor air filtration and promoting cleaner urban planning could significantly mitigate these risks.

As infertility rates rise around the world, these studies offer a potential explanation, as well as some potential solutions. Want to have more fertility in your city or country? Reducing pollution is a good place to start. After all, reducing pollution also has the important side effect of enhancing health and overall well-being.