Open Access Open Badges Research

Ozone is associated with cardiopulmonary and stroke emergency hospital visits in Reykjavík, Iceland 2003–2009

Hanne Krage Carlsen123*, Bertil Forsberg2, Kadri Meister45, Thorarinn Gíslason45 and Anna Oudin2

  • * Corresponding author: Hanne K Carlsen

Author Affiliations

1 Centre of Public Health, University of Iceland, Stapi v/Hringbraut, Reykjavik, 101, Iceland

2 Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine, Umeå University, Umeå, 901 87, Sweden

3 Occupational and Environment Medicine, Department of Public Health and Clinical Medicine, University of Gothenburg, Gothenburg, 40530, Sweden

4 Faculty of Medicine, University of Iceland, Vatnsmyrarvegur 16, Reykjavik, 101, Iceland

5 Department of Allergy and Sleep (E6), Landspitali University Hospital, Reykjavik, 108, Iceland

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Environmental Health 2013, 12:28  doi:10.1186/1476-069X-12-28

Published: 8 April 2013



Air pollution exposure is associated with hospital admissions and emergency room visits for cardiopulmonary disease and stroke. Iceland’s capital area, Reykjavik, has generally low air pollution levels, but traffic and natural sources contribute to pollution levels. The objective of this study was to investigate temporal associations between emergency hospital visits and air pollutants ozone (O3), nitrogen dioxide (NO2), and particulate matter (PM10) in the Icelandic capital area.


We constructed a time series of the daily number of adults who visited the emergency room, or were acutely admitted for stroke or cardiorespiratory causes to Landspitali University Hospital 1 January 2003 – 31 December 2009 from the hospital in-patient register. We used generalized additive models assuming Poisson distribution, to analyze the daily emergency hospital visits as a function of the pollutant levels, and adjusted for meteorological variables, day of week, and time trend with splines.


Daily emergency hospital visits increased 3.9% (95% confidence interval (CI) 1.7-6.1%) per interquartile (IQR) change in average O3 the same and two previous days. For females, the increase was 7.8% (95% CI 3.6-12.1) for elderly (70+), the increase was 3.9% (95% CI 0.6-7.3%) per IQR increase of NO2. There were no associations with PM10.


We found an increase in daily emergency hospital visits associated with O3, indicating that low-level exposure may trigger cardiopulmonary events or stroke.

Air pollution; Stroke; Cardiopulmonary; Cardiac; Cardiovascular; Hospital admissions; Emergency room visits