Sperm quality decline associated with gaseous pollutant exposure: Evidence from a large cohort multicenter study.

BACKGROUND:Poor sperm quality is a prevalent cause of male infertility, and the association between gaseous ambient air pollutants exposure and semen quality remains unclear. OBJECTIVES:To examine the relationship between gaseous air pollution exposure with semen quality in a large-scale and multi-center study. METHODS:We analyzed 78,952 samples corresponding to 33,234 study subjects from 2014 to 2020. The high-resolution grid pollution dataset was used to estimate personal exposures to CO, SO2, NO2 and O3 across entire stage of semen formation and three crucial stages. The linear mixed models were performed to evaluate the relationships. RESULTS:The results showed that sperm count was inversely related to SO2 exposure (-0.0070, -0.0128 to -0.0011). Decreased sperm concentration was associated with SO2 (-0.0083, -0.0142 to -0.0024), NO2 (-0.0162, -0.0320 to -0.0005) and O3 (-0.0306, -0.0480 to -0.0133) during 0-90 lag days, respectively. Additionally, we observed significant decline of PR and total motility with SO2 exposure. Similar trends were observed for SO2 and CO exposure during 3 key periods. CONCLUSIONS:Our findings suggest that exposure to gaseous air pollutants may have negative impacts on sperm quality. These findings highlight the importance that critical periods of sperm development should be considered when implementing protective measures.