| Using Geographic Information Systems To Assess Individual Historical Exposure to Air Pollution from Traffic and House Heating in Stockholm Tom Bellander,1,2 Niklas Berglind,1 Per Gustavsson,3 Tage Jonson,4 Fredrik Nyberg,2,5 Göran Pershagen,1,2 and Lars Järup1,2,6 1Department of Environmental Health, Stockholm County Council, Stockholm, Sweden
2Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
3Department of Occupational Health, Stockholm County Council, Stockholm, Sweden
4Environment Health Protection Administration, Slb-analys, Stockholm, Sweden
5International Agency for Research on Cancer, Lyon, France
6Department of Epidemiology and Public Health, Imperial College, London, UK Abstract
A specific aim of a population-based case-control study of lung cancer in Stockholm, Sweden, was to use emission data, dispersion models, and geographic information systems (GIS) to assess historical exposure to several components of ambient air pollution. Data collected for 1,042 lung cancer cases and 2,364 population controls included information on residence from 1955 to the end of follow-up for each individual, 1990-1995. We assessed ambient air concentrations of pollutants from road traffic and heating throughout the study area for three points in time (1960, 1970, and 1980) using reconstructed emission data for the index pollutants nitrogen oxides (NOx/NO2) and sulfur dioxide together with dispersion modeling. NO2 estimates for 1980 compared well with actual measurements, but no independently measured (study-external) data were available for SO2, precluding similar validation. Subsequently, we used linear intra- and extrapolation to obtain estimates for all other years 1955-1990. Eleven thousand individual addresses were transformed into geographic coordinates through automatic and manual procedures, with an estimated error of < 100 m for 90% of the addresses. Finally, we linked annual air pollution estimates to annual residence coordinates, yielding long-term residential exposure indices for each individual. There was a wide range of individual long-term average exposure, with an 11-fold interindividual difference in NO2 and an 18-fold difference in SO2. The 30-year average for all study subjects was 20 µg/m3 NO2 from traffic and 53 µg/m3 SO2 from heating. The results indicate that GIS can be useful for exposure assessment in environmental epidemiology studies, provided that detailed geographically related exposure data are available for relevant time periods. Key words: air pollution, combustion, epidemiology, exposure assessment, GIS, lung cancer, traffic. Environ Health Perspect 109:633-639 (2001) . [Online 15 June 2001] http://ehpnet1.niehs.nih.gov/docs/2001/109p633-639bellander/ abstract.html Address correspondence to T. Bellander, Department of Environmental Health, Norrbacka 3rd floor, Karolinska Hospital, S-176 76 Stockholm, Sweden. Telephone: +46 8 5177 7906. Fax +46 8 5177 7900. E-mail: tom.bellander@smd.sll.se The work was performed at Department of Environmental Health, Karolinska Hospital, Norrbacka, S-171 76 Stockholm, Sweden. The study was supported by the Swedish Environmental Protection Agency, the Swedish Council for Work Life Research, and the Stockholm County Council. We are indebted to C. Bengtsson, A. Boberg, E-B. Gustavsson, M. Hugosson, L-G. Hörte, R. Jakobsson, E. Junghahn, U. Klinga, A. Lauber, S. Norberg, M. Pettersson, C. Rudengren, P. Schéele, E. Skarke, A. Wahlbom, and K. Åström for valuable contributions to various aspects of the study. Received 8 February 2000 ; accepted 11 December 2000.
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