Seasonal variation of semen parameters correlates with environmental temperature and air pollution: A big data analysis over 6 years

Highlights: • This represents the first big-data approach on the complex relationship between environment and male fertility. • Semen parameters show a seasonal change, with a fluctuation during the year related to temperature and daylight duration. • Air pollution exerts a negative effect on semen quality. Male fertility is progressively declining in many developed countries, but the relationship between male infertility and environmental factors is still unclear.