I found the statistical model rather troubling. They assume that TSP is the only factor that is not continuous across Huai river, then make mathematical model to assign a coefficient to TSP to explain the mortality difference. No surprise, they find a positive link between TSP and mortality. If I replace TSP with amount of rice consumed, and pretend I know nothing about air pollution, I can arrive at a similar conclusion that rice can protect cardiovascular disease and extend life span (or wheat can shorten life span by 5 years). You can easily see how ridiculous this can be. I do not doubt air pollution causes cardiovascular deaths, but the causal relationship cannot be demonstrated with simple correlation studies, it is the same reason that black hair color is not the cause of enhanced ability to use chopsticks.