The effect of various air pollution and participants' age on semen quality in southern Taiwan.

Objective: This study aimed to investigate the association between semen quality and air pollution in southern Taiwan.
Materials and Methods: In this retrospective study, 4338 males aged 21-70 years were recruited between 2001 and 2018 from a reproductive medical center. Semen quality was assessed according to standardized methods outlined in the World Health Organization (WHO) Laboratory Manual 1999 and 2010, including total sperm count, progressive sperm motility (%), rapid progressive sperm motility (%), and sperm with normal morphology (%). All designated national air quality automatic continuous monitoring stations measured the levels of air pollution [particulate matter (PM ₁₀ and PM _2.5 ), sulfur dioxide (SO ₂ ), nitrogen dioxide (NO ₂ ), carbon monoxide (CO), ozone (O ₃ )], and was documented by Environmental Protection Administration in Taiwan. We collected data on the levels of air pollution based on the participants' residential addresses.
Results: In our study, we found that progressive and rapid progressive sperm motility significantly decreased annually (p < 0.05). In addition, increasing age influenced total sperm count, progressive sperm motility, rapid progressive sperm motility, and sperm with normal morphology (p < 0.05). Among different air pollution, we observed SO ₂ was associated with lower rapid progressive sperm motility and lower sperm with normal morphology (β = -0.103, p = 0.043; β = 0.118, p = 0.001, respectively). However, NO ₂ was associated with higher rapid progressive sperm motility and a high number of sperm with normal morphology (β = 0.129, p = 0.002; β = 0.127, p < 0.001, respectively).
Conclusions: The semen quality in southern Taiwan appears to have declined in recent years. The participant's age for semen analysis was most strongly associated with semen parameters, Moreover, a significant association between SO ₂ and NO ₂ levels and semen motility was observed, even after adjusting for multiple comparisons. Further study is required to analyze the dose-dependent effect of SO ₂ and NO ₂ on semen parameters.
Competing Interests: Declaration of competing interest The authors have no conflicts of interest relevant to this article.
(Copyright © 2023. Published by Elsevier B.V.)