The effect of ozone and PM10 on hospital admissions for pneumonia and chronic obstructive pulmonary disease: a national multicity study

Am J Epidemiol. 2006 Mar 15;163(6):579-88. doi: 10.1093/aje/kwj078. Epub 2006 Jan 27.


A case-crossover study was conducted in 36 US cities to evaluate the effect of ozone and particulate matter with an aerodynamic diameter of < or =10 microm (PM10) on respiratory hospital admissions and to identify which city characteristics may explain the heterogeneity in risk estimates. Respiratory hospital admissions and air pollution data were obtained for 1986-1999. In a meta-analysis based on the city-specific regression models, several city characteristics were evaluated as effect modifiers. During the warm season, the 2-day cumulative effect of a 5-ppb increase in ozone was a 0.27% (95% confidence interval (CI): 0.08, 0.47) increase in chronic obstructive pulmonary disease admissions and a 0.41% (95% CI: 0.26, 0.57) increase in pneumonia admissions. Similarly, a 10-microg/m(3) increase in PM10 during the warm season resulted in a 1.47% (95% CI: 0.93, 2.01) increase in chronic obstructive pulmonary disease at lag 1 and a 0.84% (95% CI: 0.50, 1.19) increase in pneumonia at lag 0. Percentage of households with central air conditioning reduced the effect of air pollution, and variability of summer apparent temperature reduced the effect of ozone on chronic obstructive pulmonary disease. The study confirmed, in a large sample of cities, that exposure to ozone and PM10 is associated with respiratory hospital admissions and provided evidence that the effect of air pollution is modified by certain city characteristics.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aged
  • Air Conditioning / statistics & numerical data
  • Air Pollutants / adverse effects*
  • Air Pollution / adverse effects*
  • Air Pollution / statistics & numerical data
  • Cross-Over Studies
  • Effect Modifier, Epidemiologic
  • Hospitals, Urban / statistics & numerical data*
  • Humans
  • Ozone / adverse effects*
  • Particle Size
  • Patient Admission / statistics & numerical data*
  • Pneumonia / epidemiology*
  • Pneumonia / etiology
  • Poverty
  • Pulmonary Disease, Chronic Obstructive / epidemiology*
  • Pulmonary Disease, Chronic Obstructive / etiology
  • Risk Assessment
  • Risk Factors
  • Seasons
  • United States / epidemiology
  • Urban Health / statistics & numerical data*


  • Air Pollutants
  • Ozone