In an excerpt from The Silent Epidemic: Coal and the Hidden Threat to Health (MIT Press, September 2012), neurologist Alan H. Lockwood examines how even if the entire cost of complying with the Clean Air Act were assumed by the federal government, we would still be vastly ahead financially.

Wisconsin Department of Natural Resources

As a part of the 1990 amendments to the Clean Air Act, Congress required the EPA to conduct "periodic, scientifically reviewed studies to assess the benefits and the costs of the Clean Air Act." In other words, Congress wanted to know whether the Act "was worth it." The initial report in what is now a series was released in October 1997. The evaluation provided a detailed retrospective analysis of costs and benefits from the years 1970 to 1990 and showed that the overwhelming benefits obtained from compliance with the Act far outweighed the costs of implementation.

MIT Press MIT Press

In the analysis the EPA used dose-response data from the scientific literature available at the time to estimate the effects of a given increment or decrement in the concentration of a given pollutant in the air. They combined these data with values associated with a given health outcome from economics data, reported in terms of cost per case, episode, symptom-day, and so forth. These data were combined with actual measurements of air quality and estimates of air quality if the controls had not been in place. Using the modeling strategies available at the time, the EPA estimated that the Act resulted in a 40 percent reduction in sulfur dioxide, a 30 percent reduction in oxides of nitrogen, a 50 percent reduction in carbon monoxide, and a 45 percent reduction in total suspended particles. The reductions in fine and larger particles were thought to be on the order of 45 percent, based on measurements of total suspended particles. Specific monitoring for particulate matter fractions had not been instituted at that time, so an extrapolation from total suspended particles was required.

The improvements in air quality were thought to be primarily due to reductions in particulate matter and ozone. In this retrospective analysis, the modeling predicted an annual reduction of 184,000 premature deaths, 674 cases of chronic bronchitis, over 22 million lost days at work, and other outcomes.

The EPA concluded that the total monetized health benefits from the Act during the 20-year period ranged between $5.6 and $49.4 trillion. The central estimate for benefits was $22.2 trillion. During that period, the costs to comply with the act were estimated to be approximately $0.5 trillion. Thus the net direct benefits were between $5.1 and $48.9 trillion, with a central estimate of $21.7 trillion. The benefit-cost rations were 43.4:1 for the central estimate and 11:1 and 97.8:1 for the extreme estimates. Who among us has an investment that has performed this well?