The effects of pollution are often greatly intensified by an unwise life-style. “Persons who work with asbestos have a seven or eight times greater risk of dying from lung cancer than the normal population. However, if they smoke,” revealed Dr. Selikoff, “they have a risk that is 92 times greater.” Smoking is one of the reasons that indoor pollution in many places is worse than pollution outside and often is a greater health hazard.

City air pollution is widely believed capable of causing or aggravating chronic heart and lung disease, especially among the elderly, infirm and newborn. However, to what extent is still debatable; better controls have helped in some cities. Yet air pollution adds stress. One study revealed that among the middle-class population of a large city in the United States, in high pollution areas there were 80 percent more deaths from heart disease due to high blood pressure than there were in low pollution areas.