Urban Air Pollution And Asthma And Copd Hospital Emergency Room Visits

¹ National public Health Institute, Finland
² Institute of Epidemiology, GSF- Helmholtz Zentrum München, Germany
³ National Public Health Institute, Finland
⁴ University of Helsinki, Finland

^* To whom correspondence should be addressed. E-mail: jaana.halonen{at}ktl.fi.

Accepted 22 January 2008

	Abstract

Rationale: 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 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: We measured the levels of particulate air pollution, NO2, and CO in 1998-2004 at central outdoor monitoring sites in Helsinki, Finland. We evaluated associations between daily pollution levels and hospital emergency room visits 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).

Measurements and Main Results: We found 3 to 5 days lagged increases in the asthma visits among children in association with nucleation (<0.03µm), Aitken (0.03-0.1µm) and accumulation (0.1-0.29µm) mode particles, gaseous pollutants, and traffic-related PM2.5 (7.8% [95% CI 3.5-12.3] for 1.1µg/m3 increase in traffic-related PM2.5 at lag 4). Pooled asthma-COPD visits among 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 0.28-7.7] 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 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.

Keywords: Asthma, Epidemiology, PM, Respiratory, Ultrafine particles