An international group of researchers studied the results of analysis of sperm samples of 6,475 men and stated: there is a relationship between the level of air pollution by finely dispersed particles and the probability of development of anomalies in the shape of spermatozoa. Scientists suggest that air pollution can be one of the causes of the spread of male infertility.

Participants in the study were Taiwanese aged 15 to 49 years. Air pollution is Taiwan's main environmental problem. There are several sources of solid fine particles polluting the air of the island. These include businesses located on Taiwan itself, also the wind brings the emissions of Chinese factories. Contributing to pollution are popular motorcycles and scooters on the island. Ecology is harmed even by local religious customs, for example burning incense and ritual money.

Men underwent a standard physical examination between 2001 and 2014. Their semen was examined by several traditional methods, including analysis of sperm concentration, their mobility and morphology. This information was compared with satellite data on airborne concentrations of pollutant PM2. 5 is a suspension of microscopic liquid droplets and fine particles with a diameter of up to 2.5 micrometers.

Combining the data showed that there is a persistent relationship between high levels of contamination and anomalies in the shape of spermatozoa. Each additional 5 micrograms of particles per cubic meter of air reduced the indicator of the correspondence of the morphology of spermatozoa to a norm of 1. 29%. Dependence was maintained even in view of potential risk factors - the weight and age of a man, smoking and drinking alcohol. How pollution affects the shape of spermatozoa is still unknown.

Scientists believe that the harm can cause microparticles of heavy metals and polycyclic aromatic hydrocarbons.

The expert in the field of andrology, Allan Pacey, called the study interesting, but specified that the evaluation of sperm morphology is a rather complicated method of analysis. Such data may be less accurate than the evaluation of sperm quality by other methods. The authors of the new work emphasize: statistically the indicator of dependence is small. However, if the dependence exists, it can still negatively affect the quality of life of many people.