de Staud, there were 1,460,700cases of hypertension<sup>in the country in 1988. Assuming that all cases</sup> were uniformly distributed in the country<sup>(this is conservative since urban areas, and specially Mexico</sup> City, tend to have a higher incidence<sup>of the disease), there should have been 321,270 cases of</sup> hypertension in Mexico City in 1990.<sup>The elimination of lead in MeKico City's air (from 1,37 pg/m3</sup> to zero) would thus lead to a reduction of 70,422<sup>cases of hypertension in MCMA.</sup> According to EPA (1985), people with<sup>hypertension see a physician because of high</sup> blood pressure an average of 3.27 times<sup>per year. Using the estimate of US$20 per visit gives a total</sup> annual cost in Mexico City of US$4.6<sup>million. The same population is forced to remain in bed an</sup> average of 0.41 days per year; considering<sup>the daily wage of US$32 gives a total cost of US$925,000.</sup> Additionally, 30 percent of the hypertense<sup>population needs medication; assuming an annual cost of</sup> US$100 (half that in the U.S.) gives a total<sup>cost of US$2.1 million. Finally, for the U.S. there was</sup> a relation between the number of hospital bed-days<sup>of 0.058per person per year due to hypertension</sup> alone. Using this same statistic to the Mexican<sup>case would give 4,084 hospital bed-days per year in</sup> Mexico City which, for a daily cost of US$50,<sup>gives a total value of only US$205,000. Adding up all</sup> components, the total estimated costs<sup>due tc hypertension morbidity in Mexico City is US$7.85</sup> million.

Myocardial infarctions (MI). The reduction<sup>of hypertension is less important than the</sup> indirect benefits in the form of reduced cardiovascular<sup>disease associated with elevated blood pressure</sup> levels. It is estimated that 60 percent of MI<sup>occur in people with blood pressure greater than 90</sup> (based on Framingham Study, McGee el al. 1976<sup>apud EPA 1985, plus some simple adjustments and</sup> estimates). Since the elimination of lead<sup>from air would lead to a 21.9 percent reduction in the</sup> probability of blood pressure being greater<sup>than 90, there would be an expected reduction of 13.1</sup> percent in the number of MI (0.219 x 0.6).<sup>According to the Anuario Estadistico (Secretaria de</sup> Salud 1988) there were 3,794 MI in Mexico<sup>City in 1990. Thus an estimated 498 cases of MI would</sup> be eliminated.

The co-ts associated with treatment of MI are also<sup>based on EPA (1985). In the U.S.,</sup> they amount to US$18,000 per case. Assuming<sup>that the costs of treatment of MI are half those</sup> observed in the U.S. (rather than 1/15,because<sup>of intense technology requirements), the overall costs</sup> would be US$4.5 million. Additionally,<sup>there are lost earnings because of reduced workdays. Using</sup> the same values and procedures as with<sup>particulates and applying such foregone earnings to all 498</sup> cases gives an additional cost of US$31.1<sup>million. The treatment costs of MI would be US$36.5</sup> million. However, still based on EPA 1985,<sup>of all cases of Ml, 22.5 percent are sudden deaths, while</sup> the remaining 77.5 percent were fatal or<sup>nonfatal MIs. We assume that 50 percent were nonfatal Ml.</sup> Therefore, the costs of treatment are only<sup>US$18.25 million (36.5 million x 50%). The fatal cases</sup> (498 x 27.5% = 137 cases) cost US$1.25<sup>million (treatment cost = US$9,000 x 137) plus US$10</sup> million (value of lives = 137 x US$75,000).<sup>And the sudden death cases cost US$8.4 million (112</sup> cases xUS$75,000). The total estimated<sup>costs associated to myocardial infarctions isthus US$40 million.</sup> 19