Objective To analyze the effects of air pollutants on male semen quality and different stages of sperm development in Taiyuan. Methods Totally 7 614 men who were admitted to the Reproductive Department of the First Hospital of Shanxi Medical University from January 1 to December 31, 2019 were enrolled. Their age, semen collection season, and semen parameters were recorded. At the same time, the monitoring data of six air pollutants (SO₂, NO₂, CO, O₃, PM_2.5, and PM₁₀) were collected, and the exposure of air pollutants in the whole developmental period (0 to 90 days before semen collection) and three critical developmental periods (0-9 days, 10-14 days, and 70-90 days) were calculated. Nonparametric Mann-Whitney U test was used to compare the data difference between qualified and unqualified semen parameters. The generalized estimation equation was used to explore the effects of six kinds of air pollutants on the quality parameters of each sperm at different stages of sperm development. Results During the whole period of sperm development, the exposure concentrations of SO₂, NO₂, O₃, and PM_2.5 were different between the qualified and unqualified groups of normal sperm morphology. The exposure to PM₁₀ at 10 and 14 days before semen collection was positively correlated with semen volume (OR=1.245, 95%CI: 1.057-1.467), sperm concentration (OR=1.247, 95%CI: 1.027-1.514), total sperm count (OR=1.385, 95%CI: 1.167-1.643), total motility (OR=1.236,95%CI: 1.085-1.409), and forward movement (OR=1.207, 95%CI: 1.059-1.376). The O₃ exposure was positively correlated with sperm concentration (OR=1.250, 95%CI: 1.002-1.558; OR=1.173, 95%CI: 1.025-1.343), total sperm count (OR=1.255,95%CI: 1.026-1.537; OR=1.218, 95%CI: 1.074-1.380), and normal sperm morphology (OR=1.295, 95%CI: 1.047-1.602; OR=1.229, 95%CI: 1.076-1.404). Conclusion Exposure to air pollutants increases the risk of unqualified semen parameters at all stages of sperm development, and the critical window period focuses on 10-14 days before semen collection, which is the developmental stage of sperm motility. PM₁₀ and O₃ are the main reproductive toxins affecting the decline of male sperm quality in Taiyuan, which need to be paid attention to.