Association between environmental particulate matter exposure and semen quality: a retrospective study

Objective To evaluate associations between ambient particulate matter (PM 2.5 and PM 10 ) exposure during spermatogenesis and semen quality, identify potentially sensitive exposure windows, and assess the robustness and seasonal heterogeneity of these associations. Methods This retrospective study included 4,448 men who underwent semen analysis at Urumqi Maternal and Child Health Hospital between March 2021 and December 2023. Residential PM 2.5 and PM 10 exposures were estimated for five pre-examination windows (0–9, 10–14, 15–69, 70–90, and 0–90 days). Multivariable linear regression models adjusted for age, abstinence duration, season, and the first principal component of gaseous pollutants. False discovery rate correction, dose–response, sensitivity, quantitative bias, and stratified analyses were performed. Results Higher PM 2.5 and PM 10 exposures were primarily associated with lower sperm concentration and total sperm count. Per interquartile-range increase in PM 2.5 , sperm concentration and total sperm count decreased by 13.57 and 12.29%, respectively, during the 0–90-day window, and by 11.49 and 10.21% during the 15–69-day window. Corresponding decreases for PM 10 were 6.17 and 5.84% during the 0–90-day window and 6.32 and 5.69% during the 15–69-day window. These associations remained significant after false discovery rate correction. Motility associations were inconsistent overall and varied by season. Conclusion Ambient PM 2.5 and PM 10 exposure was associated with reduced sperm concentration and total sperm count, with the 15–69-day window showing relatively consistent evidence of susceptibility. Motility associations were less stable and showed seasonal heterogeneity.