On the basis of the five-year study (1984-1988) presented herein, we have been able to demonstrate that, under conditions of smog, an increase in respiratory diseases can occur. Our results also show that cardiovascular diseases decrease simultaneously, an observation that has not so far been reported in the literature. A possible reason for this observation is, perhaps, an information effect, or an influence effect induced by warnings given in the media about the negative health-related consequences for those who leave their homes, in particular those consequences applicable to patients with cardiovascular disorders. The pathological process is traceable to a multifactorial occurrence, the temperature of the air having a decisive influence. To date, the influence of indoor pollution has not yet been clarified.