From the paper's abstract, though, "The results suggest that a 10% reduction in daily PM2.5 and ozone could save $1.4 billion in crime costs per year, a previou

From the paper's abstract, though, "The results suggest that a 10% reduction in daily PM2.5 and ozone could save $1.4 billion in crime costs per year, a previously overlooked cost associated with pollution." This statement sounds like it's implying a causal relationship to me.