Air quality, tobacco smoke, urban crowding and day care: modern menaces and their effects on health

Pediatr Infect Dis J. 2005 Nov;24(11 Suppl):S152-6, discussion S156-7. doi: 10.1097/01.inf.0000188152.49558.49.


Background: The known adverse health effects of outdoor air pollution were reduced in the last century by effective legislation and pollution control. Although combustion of biomass fuels in the indoor environment remains a major hazard in developing countries, there has been a change in the nature of the traffic-generated air pollutants in outdoor air in developed countries. The role of day care and siblings in increasing the risk of infection early in life contrasts with protection from allergic disease later.

Methods: The mechanisms of how these pollutants exert their effects are poorly understood, but there is emerging evidence that the toxic effects may be related to infection. This synopsis discusses the epidemiologic relationship of the menaces of modern living, including air pollution, urban crowding and infection, and will explore some of the mechanisms of how they act synergistically to cause exacerbations of illnesses in individuals with preexisting respiratory conditions, such as asthma. It will also discuss the roles of day care and siblings in relation to respiratory disease risk.

Results: Current evidence suggests that much of the morbidity and mortality related to sources of both indoor and outdoor pollution occur by causing or interacting with respiratory infection and other acute or chronic health conditions, such as asthma.

Conclusion: Improvements in air quality through efforts to tackle environmental problems such as pollution and tobacco smoke will help achieve better health. Day care and siblings increase infectious disease early in life but are associated with protection against development of allergic disease later.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adolescent
  • Adult
  • Air Pollution / adverse effects*
  • Asthma / chemically induced
  • Child
  • Child Day Care Centers*
  • Child, Preschool
  • Crowding*
  • Female
  • Humans
  • Infant
  • Male
  • Respiratory Tract Diseases / chemically induced*
  • Tobacco Smoke Pollution / adverse effects
  • Urban Population*


  • Tobacco Smoke Pollution