Air pollution seems to be shrinking human sperm
We have all seen that dystopian film, the one where fertility drops and humans stop producing babies, eventually causing the complete collapse of civilisation as we know it. But that’s just fiction, right? Maybe not. Thanks to the collective effort from humanity to pollute the air, mass male infertility might not just be something seen in works of fiction like The Handmaid’s Tale.
Back in July, a study from the Hebrew University of Jerusalem reported that the sperm count of men had completely halved in the last 40 years in the Western world, with the concentration of sperm falling by 1.4% each year. However, the scientists were not able to pinpoint why exactly it was happening. Now we might have our answer, and it could be due to air pollution.
A new study from the Chinese University of Hong Kong suggests that there is a strong relationship between fine particulate matter (PM) found in areas with high levels of air pollution and the abnormal shape of sperm. These air particles, which are less than 2.5 micrometres in size, are to blame for the decline in human sperm quality.
The team, led by Dr. Lao Xiang Quian took the sperm quality data of 6,475 15-49 year old men in Taiwan from donors between 2001-2014. After matching their sperm quality data with the levels of pollution and fine particulate matter at their home addresses, they were able to see the association between air pollution and sperm quality.
The researchers observed a significant match between high levels of ambient particulate matter less than 2.5 micrometres in size and the shape, level of activity and quality of the sample sperm.
“A strong association between PM2.5 exposure and abnormal sperm shape was found. Every 5 ug/m3 increase in fine particulate matter across the two-year average was associated with a significant drop in normal sperm shape/size of 1.9%,” the study reads. “It was associated with a 26% heightened risk of being in the bottom 10% of normal sperm size and shape, after taking account of potentially influential factors, such as smoking and drinking, age or overweight.”
This damage could be due to free radicals in air pollutants, something that could alter DNA. While the effects appear to be small, the researchers stress that this is just in a clinical setting.
“This is an important public health challenge,” the study states. “Given the ubiquity of exposure to air pollution, a small effect size of PM 2.5 on sperm normal morphology may result in a significant number of couples with infertility.”
The negative effects of air pollution on the rate of mortality has been widely publicised in the past, with reports suggesting that 6.6 million people will die every year due to air pollution by the year 2050.
A study published in The Lancet found that PM2.5 is the most deadly component in air pollution as it can be absorbed into the bloodstream and settle into people’s lungs. Half a million people in India are to have died prematurely in 2015 due to PM2.5. Maybe it’s time we woke up and got to work cleaning up the air, or the Handmaid’s Tale might feel even more real than it already does.