Background: There is little previous information of the effects of size fractioned particulate air pollution and source specific fine particles (PM2.5; <2.5 μm) on asthma and chronic obstructive pulmonary disease (COPD) among children, adults and the elderly.
Objectives: To determine the effects of daily variation in levels of different particle size fractions and gaseous pollutants on asthma and COPD by age group.
Methods: Levels of particulate air pollution, NO2 and CO were measured from 1998 to 2004 at central outdoor monitoring sites in Helsinki, Finland. Associations between daily pollution levels and hospital emergency room visits were evaluated for asthma (ICD10: J45+J46) in children <15 years old, and for asthma and COPD (ICD10: J41+J44) in adults (15–64 years) and the elderly (⩾65 years).
Results: Three to 5 day lagged increases in asthma visits were found among children in association with nucleation (<0.03 μm), Aitken (0.03–0.1 μm) and accumulation (0.1–0.29 μm) mode particles, gaseous pollutants and traffic related PM2.5 (7.8% (95% CI 3.5 to 12.3) for 1.1 μg/m3 increase in traffic related PM2.5 at lag 4). Pooled asthma–COPD visits among the elderly were associated with lag 0 of PM2.5, coarse particles, gaseous pollutants and long range transported and traffic related PM2.5 (3.9% (95% CI 0.28 to 7.7) at lag 0). Only accumulation mode and coarse particles were associated with asthma and COPD among adults.
Conclusions: Among children, traffic related PM2.5 had delayed effects, whereas among the elderly, several types of particles had effects that were more immediate. These findings suggest that the mechanisms of the respiratory effects of air pollution, and responsible pollutants, differ by age group.
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Tables S1, S2 and S3, figs S1 and S2, and supplementary data are published online only at http://thorax.bmj.com/content/vol63/issue7
Funding: The study was financially supported by the Centre of Excellence Programme 2002–2007 of the Academy of Finland (Contract 53307), the National Technology Fund (TEKES, Contract 40715/01) and the Ministry of Education (Graduate School in Environment Health SYTYKE).
Competing interests: None.
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