Objective To discuss the differential susceptibility of children to environmental exposures using mortality rates for children and adults for infectious respiratory and gastrointestinal problems.

Materials and Methods We conducted an ecological study. We examined the trend in mortality rate from acute respiratory infections and acute diarrhoeal diseases and compared this with the consumption of chlorofluorocarbons—CFCs (air pollutant) and coverage of sewage services in Brazil. We used the polynomial regression model for assessment of trends, which were compared according to age categories with air pollution or water pollution proxy).

Results The consumption of CFCs was associated with increased mortality from the respiratory infection Agura. Increased sewage service coverage was associated with reduced mortality. This relationship was more pronounced in children than in adults.

Conclusion This new knowledge about children and susceptibility to environmental agents will help to identify subgroups and allow age sensitive planning of preventive actions.