But air pollution's impact on cognition is a well-studied topic. See e.g: https://www.pnas.org/content/115/37/9193, https://www.sciencedirect.com/science/article/pii/S019701862..., and especially https://jech.bmj.com/content/64/3/223.short: "Although results were not statistically significant, the associations found between exposure to NO2 and cognitive functions suggest that traffic-related air pollution may have an adverse effect on neurodevelopment, especially early in life, even at low exposure levels." In other words, air pollution makes you dumb and being male and dumb makes you more prone to commit crime. I find no reason not to believe that this may be a significant factor.