Everyone knows that air pollution is bad for our lungs-- as well as for plants and animals. It is responsible for holes in the ozone layer-- as well as a significant contributor to the global rise in the Earth’s temperature. Air pollution is even scarier because it cannot be seen-- but it still has a drastic effect on our lungs. It could also be causing problems in our endocrine systems as well-- according to research done at Sao Paulo University. The study showed that air pollution could be affecting the endocrine systems of humans-- which is involved in reproduction. In this article, we’ll discuss:

• The effect of air pollution on mice
• What does this mean for humans?
• Does this mean there will be a rise in male infertility?

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The Effect of Air Pollution on Mice

This problem was researched at the University of Sao Paulo, and was presented to ENDO, the Endocrine Society’s annual meeting. The researchers were looking to see if there were any substantial effects on mice when they were exposed to air pollution. However, this study looked at its particular effect on sperm production-- which is controlled by the endocrine system in mammals. In order to do so, they examined PM2.5, which is an inhalable particle with diameters of 2.5 micrometers or smaller. This type of particular is about 30 times smaller than a human hair follicle-- and researchers know that exposure to particles like this result in breathing and heart complications. It is also known to disrupt the function of the endocrine system, and thus the production of sperm in males.

This study examined four groups of mice:

1. A group exposed to PM2.5 from before birth and all the way until adulthood
2. A group exposed only during gestation
3. A group exposed after birth and until adulthood
4. A group exposed to only filtered air from gestation until adulthood

The study then looked at the testes and the production of sperm. The researchers concluded that the sperm of all of the mice exposed to PM2.5 were worse off than the ones only exposed to filtered air. The worse sperm quality was seen in the mice that were exposed during gestation all the way to adulthood. It seems that the effects of air pollution were the most detrimental after birth-- it changed the genes related to testicular function.

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What Does This Mean for Humans?

The results of this study show that exposure to the air pollution of a large city-- in this case Sao Paulo-- can result in worsening sperm production and low sperm quality. The worst effects were seen after birth and during crucial developmental years. Many cities do not have major air pollution control policies-- and this is not only worsening the lungs of their inhabitants-- but also the male reproductive system.

In the U.S., the EPA has set National Ambient Air Standards that put a limit on safe exposure to PM2.5-- but this may not be the case in other areas of the world. With little to no regulation, we could see a rise of a whole new set of problems that come from increased exposure to air pollution-- and it seems that sperm quality may also be an unwanted side effect as well.

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Will Air Pollution Increase Male Infertility?

The World Health Organization (WHO) estimates that approximately 15% of the world’s population is dealing with issues related to infertility-- half of that is male infertility. Air pollution is already doing a lot of damage-- and not just to humans-- to the environment as a whole. The study in mice proved that it might also be contributing to male infertility as well. Air pollution exposure caused an epigenetic change in the testicular cells of the mice-- which means these changes were not caused by a DNA sequence anomaly. These types of changes can turn on or turn off a gene-- as well as determine how the gene is expressed.

This isn’t good news for men who may have been affected by air pollution as they were growing up. They way that their testicular cells function has been altered-- and as of yet there is no way to change it back. This is why it is imperative that air pollution policies be enacted for larger cities across the world. Men dealing with infertility often don’t know the cause-- and it’s scary to think that exposure to harmful PM2.5 in air pollution is the reason why.

Air pollution has a serious effect on the health of all the organisms of the world, including humans. We breathe in these harmful particles daily-- and do not see the results of it until it has manifested into a serious problem such as lung disease or heart issues. It seems now it could be having detrimental effects on the sperm quality of men across the globe-- and contributing to their infertility.