Traffic-related air pollution and childhood respiratory symptoms, function and allergies

Epidemiology. 2008 May;19(3):401-8. doi: 10.1097/EDE.0b013e31816a1ce3.


Background: Urban air pollution can trigger asthma symptoms in children, but there is conflicting evidence on effects of long-term exposure on lung function, onset of airway disease and allergic sensitization.

Methods: The spatial distribution of nitrogen oxides from traffic (traffic-NOx) and inhalable particulate matter from traffic (traffic-PM10) in the study area was assessed with emission databases and dispersion modeling. Estimated levels were used to assign first-year exposure levels for children in a prospective birth cohort (n = 4089), by linking to geocoded home addresses. Parents in 4 Swedish municipalities provided questionnaire data on symptoms and exposures when the children were 2 months and 1, 2, and 4-year-old. At 4 years, 73% of the children underwent clinical examination including peak expiratory flow and specific IgE measurements.

Results: Exposure to air pollution from traffic during the first year of life was associated with an excess risk of persistent wheezing (odds ratio [OR] for 44 microg/m3 [5th-95th percentile] difference in traffic-NOx = 1.60; 95% confidence interval [CI] = 1.09-2.36). Similar results were found for sensitization (measured as specific IgE) to inhalant allergens, especially pollen (OR for traffic-NOx = 1.67; 95% CI = 1.10-2.53), at the age of 4 years. Traffic-related air pollution exposure during the first year of life was also associated with lower lung function at 4 years of age. Results were similar using traffic-NOx and traffic-PM10 as indicators.

Conclusions: Exposure to moderate levels of locally emitted air pollution from traffic early in life appears to influence the development of airway disease and sensitization in preschool children.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Child, Preschool
  • Environmental Exposure / adverse effects*
  • Environmental Exposure / analysis
  • Female
  • Humans
  • Hypersensitivity / epidemiology*
  • Hypersensitivity / etiology
  • Hypersensitivity / physiopathology
  • Immunoglobulin E / analysis
  • Infant
  • Male
  • Nitrogen Oxides / adverse effects*
  • Nitrogen Oxides / analysis*
  • Particulate Matter / adverse effects*
  • Particulate Matter / analysis
  • Prospective Studies
  • Regression Analysis
  • Respiratory Function Tests
  • Respiratory Tract Diseases / epidemiology*
  • Respiratory Tract Diseases / etiology
  • Respiratory Tract Diseases / physiopathology
  • Risk Factors
  • Socioeconomic Factors
  • Surveys and Questionnaires
  • Sweden / epidemiology
  • Vehicle Emissions / analysis*


  • Nitrogen Oxides
  • Particulate Matter
  • Vehicle Emissions
  • Immunoglobulin E