In the case of burning coal, the process of scrubbing mercury from the emissions also significantly reduced the output of particles that feed smog and cause a variety of respiratory problems — the co-benefit. The cost of cutting the mercury emissions was put at $9.6 billion while the direct public health benefits were was estimated at $6 million. But when the co-benefits from reduced soot, nitrous oxide and related emissions were added in, the estimated public health benefit ranged from $37 billion to $90 billion. Those benefits included a reduction in health costs, a drop in lost work days and the avoidance of as many as 11,000 premature deaths. (Some 4,700 heart attacks would be prevented.) Clearly the broad benefits from eliminating mercury exceeded the costs industry faced in doing so.
Source: latimes.com – Los Angeles Times