Associations of exposure to ambient fine particulate matter constituents from different pollution sources with semen quality: Evidence from a prospective cohort.

The association between ambient fine particulate matter (PM) exposure and semen quality remains inconclusive, possibly due to variations in pollution sources and PM compositions. Studies investigating the constituents of PM have been hindered by small sample sizes, and research exploring the relationships between PM pollution sources and semen quality is lacking. To address this gap, we conducted a comprehensive study based on the Anhui prospective assisted reproduction cohort to evaluate the associations between semen quality and the constituents and pollution sources of PM. This study included 9013 semen samples from 4417 males in the urban districts of Hefei. The median concentrations of PM constituents, including eight metals and four water-soluble ions (WSIs), were measured for seven days per month at two monitoring stations during the 0-90-day exposure window. A linear mixed-effects model, weighted quantile sum regression, and positive matrix factorisation were used to evaluate the associations of the constituents and pollution sources of PM with semen quality. The results showed that exposure to PM-bound metals (antimony, arsenic, cadmium, lead, and thallium) and WSIs (sulphate and chloride) were negatively associated with semen quality parameters. Moreover, mixtures of PM-bound metals and WSIs were negatively associated with semen quality. Additionally, PM derived from traffic emissions was negatively associated with semen quality. In summary, our study revealed that ambient PM and its constituents, especially metals, were negatively associated with semen quality. Antimony, lead, and thallium emerged as the primary contributors to toxicity, and PM from traffic emissions was associated with decreased semen quality. These findings have important public health implications for the management of PM pollution in the context of male reproductive health.