Air pollution and decreased semen quality: A comparative study of Chongqing urban and rural areas.

To investigate the association and effects of air pollution level on male semen quality in urban and rural areas, this study examines the outdoor concentrations of particulate matter (PM₁₀), sulfur dioxide (SO₂), nitrous dioxide (NO₂) and semen quality outcomes for 1346 volunteers in both urban and rural areas in Chongqing, China. We found the urban area has a higher pollution level than the rural area, contrasted with better semen quality in the rural residents, especially for sperm morphology and computer assistant semen analysis (CASA) motility parameters. A multivariate linear regression analysis demonstrates that concentrations of PM₁₀, SO₂, and NO₂ significantly and negatively are associated with normal sperm morphology percentage (P < 0.001) and sperm kinetic parameters. In conclusion, exposure to higher concentrations of PM₁₀, SO₂, and NO₂ in urban ambient air may account for worse semen quality in urban males. [Copyright &y& Elsevier]