The council considered Wolff's issues and ultimately decided to proceed with the approach described here. Crandall, Rueter, and Steger speculate that the observed relationship between PM and mortality is really due to indoor air, because higher levels of PM occur when there is stagnant weather, which in turn reduces the exchange of indoor air to the outside, thereby causing a buildup of indoor pollution and the observed mortality increase. They fail to mention the strong longitudinal correlation between indoor and outdoor levels of fine particles, confirmed in studies conducted in twenty-four different North American cities. The critique by Crandall et al. of the lead benefits analysis is also flawed. Indeed, the biological link between hypertension and heart disease and stroke is among the most clear-cut in medicine.
Recent findings tie elevated blood-lead levels to increased hypertension.
Treatment of hypertension is not predicated on cofactors such as smoking or obesity. Further, the coefficients relating blood pressure and health effects were explicitly adjusted for age, smoking, and serum cholesterol levels. As for the valuation of premature mortality, Crandall et al. suggest a lower value, particularly for PM, where the number of life-years shortened may be quite small. Not surprisingly, the benefits do decrease, but they still exceed costs by more than an order of magnitude. Crandall et al.