“…Rumel and colleagues (1993) 46 studied the occurrence of visits to emergency services for acute myocardial infarction and found an association with levels of carbon monoxide (CO) and ambient temperature. In an experimental study, Reymão and colleagues (1997) 47 suggest that air pollution may facilitate the formation of certain types of lung cancer in rats. However, the ecological character of some these studies, the lack of specificity regarding the age groups most susceptible and the various health effects, the short period of investigation (usually one year), which hampers control of temporal trends and the short careful control of meteorological variables, among other issues, prevented a better assessment of the effects of air pollution on health in the Brazilian context.…”