Abstract
BACKGROUND AND OBJECTIVE: With the rapid development of modern production and daily life, human fertility has shown a declining trend, with male factors accounting for approximately half of the cases. Declining sperm quality is the primary issue in male infertility, and environmental factors play a significant role in its development. This paper aims to thoroughly explore the impact of environmental factors on male sperm quality and provide insights for the etiology and prevention of male infertility. METHODS: A comprehensive literature search was conducted in PubMed from its inception to June 25, 2025, for articles on the effects of traditional environmental factors on male sperm quality. 84.9% of the references were published between 2020 and 2025, with most studies being recent and related to human male fertility. The search included all articles containing the following keywords: "sperm quality", "environmental factors", "temperature", "heavy metals", "pesticide", "phthalate", "viruses", "bacteria", "Radiofrequency Electromagnetic Radiation (RF-EMR)", "per- and polyfluoroalkyl substances (PFAS)", "air pollution", "Benzo[a]pyrene (BaP)", and "microbiome". The retrieved articles were reviewed to summarize the effects of environmental factors on male sperm quality. KEY CONTENT AND FINDINGS: A total of 250 articles were identified with these keywords and later screened for inclusion. We finally included 82 publications that were relevant to our topic. Based on recent studies within China and international research, this paper not only examines the effects of traditional pollutants at the molecular mechanism level but also focuses on emerging environmental factors such as the synergistic toxicity of new environmental pollutants-PFAS, and heavy metals-as well as 5G radiofrequency radiation. These environmental factors significantly reduce sperm concentration, motility, morphological integrity, and DNA stability through multiple mechanisms and systemic effects-including reactive oxygen species (ROS), endocrine disruption, DNA damage, and inflammatory responses-thereby impairing male fertility. CONCLUSIONS: Traditional and emerging environmental factors synergistically impair male sperm quality through multiple mechanisms, including oxidative stress, endocrine disruption, epigenetic alterations, and systemic inflammation. Future experimental research should shift from single-pollutant studies to real-world mixture exposure investigations, utilizing multi-omics technologies to deeply analyze epigenetic mechanisms and transgenerational effects. Clinically, environmental risk factors should be incorporated into routine screening and counseling for male infertility, with enhanced antioxidant intervention measures. At the policy level, there is an urgent need to improve chemical regulation to prevent potentially stronger reproductive toxicity from novel substitutes and to enhance air pollution control. Curbing the global decline in fertility at its source holds significant importance for advancing population reproductive health.